USB: work around for EHCI with quirky periodic schedules
[safe/jmp/linux-2.6] / drivers / usb / host / ehci-sched.c
index ebcca97..a5535b5 100644 (file)
@@ -1,7 +1,7 @@
 /*
  * Copyright (c) 2001-2004 by David Brownell
  * Copyright (c) 2003 Michal Sojka, for high-speed iso transfers
- * 
+ *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License as published by the
  * Free Software Foundation; either version 2 of the License, or (at your
@@ -44,9 +44,10 @@ static int ehci_get_frame (struct usb_hcd *hcd);
  * @tag: hardware tag for type of this record
  */
 static union ehci_shadow *
-periodic_next_shadow (union ehci_shadow *periodic, __le32 tag)
+periodic_next_shadow(struct ehci_hcd *ehci, union ehci_shadow *periodic,
+               __hc32 tag)
 {
-       switch (tag) {
+       switch (hc32_to_cpu(ehci, tag)) {
        case Q_TYPE_QH:
                return &periodic->qh->qh_next;
        case Q_TYPE_FSTN:
@@ -59,17 +60,33 @@ periodic_next_shadow (union ehci_shadow *periodic, __le32 tag)
        }
 }
 
+static __hc32 *
+shadow_next_periodic(struct ehci_hcd *ehci, union ehci_shadow *periodic,
+               __hc32 tag)
+{
+       switch (hc32_to_cpu(ehci, tag)) {
+       /* our ehci_shadow.qh is actually software part */
+       case Q_TYPE_QH:
+               return &periodic->qh->hw->hw_next;
+       /* others are hw parts */
+       default:
+               return periodic->hw_next;
+       }
+}
+
 /* caller must hold ehci->lock */
 static void periodic_unlink (struct ehci_hcd *ehci, unsigned frame, void *ptr)
 {
-       union ehci_shadow       *prev_p = &ehci->pshadow [frame];
-       __le32                  *hw_p = &ehci->periodic [frame];
+       union ehci_shadow       *prev_p = &ehci->pshadow[frame];
+       __hc32                  *hw_p = &ehci->periodic[frame];
        union ehci_shadow       here = *prev_p;
 
        /* find predecessor of "ptr"; hw and shadow lists are in sync */
        while (here.ptr && here.ptr != ptr) {
-               prev_p = periodic_next_shadow (prev_p, Q_NEXT_TYPE (*hw_p));
-               hw_p = here.hw_next;
+               prev_p = periodic_next_shadow(ehci, prev_p,
+                               Q_NEXT_TYPE(ehci, *hw_p));
+               hw_p = shadow_next_periodic(ehci, &here,
+                               Q_NEXT_TYPE(ehci, *hw_p));
                here = *prev_p;
        }
        /* an interrupt entry (at list end) could have been shared */
@@ -79,28 +96,32 @@ static void periodic_unlink (struct ehci_hcd *ehci, unsigned frame, void *ptr)
        /* update shadow and hardware lists ... the old "next" pointers
         * from ptr may still be in use, the caller updates them.
         */
-       *prev_p = *periodic_next_shadow (&here, Q_NEXT_TYPE (*hw_p));
-       *hw_p = *here.hw_next;
+       *prev_p = *periodic_next_shadow(ehci, &here,
+                       Q_NEXT_TYPE(ehci, *hw_p));
+       *hw_p = *shadow_next_periodic(ehci, &here, Q_NEXT_TYPE(ehci, *hw_p));
 }
 
 /* how many of the uframe's 125 usecs are allocated? */
 static unsigned short
 periodic_usecs (struct ehci_hcd *ehci, unsigned frame, unsigned uframe)
 {
-       __le32                  *hw_p = &ehci->periodic [frame];
+       __hc32                  *hw_p = &ehci->periodic [frame];
        union ehci_shadow       *q = &ehci->pshadow [frame];
        unsigned                usecs = 0;
+       struct ehci_qh_hw       *hw;
 
        while (q->ptr) {
-               switch (Q_NEXT_TYPE (*hw_p)) {
+               switch (hc32_to_cpu(ehci, Q_NEXT_TYPE(ehci, *hw_p))) {
                case Q_TYPE_QH:
+                       hw = q->qh->hw;
                        /* is it in the S-mask? */
-                       if (q->qh->hw_info2 & cpu_to_le32 (1 << uframe))
+                       if (hw->hw_info2 & cpu_to_hc32(ehci, 1 << uframe))
                                usecs += q->qh->usecs;
                        /* ... or C-mask? */
-                       if (q->qh->hw_info2 & cpu_to_le32 (1 << (8 + uframe)))
+                       if (hw->hw_info2 & cpu_to_hc32(ehci,
+                                       1 << (8 + uframe)))
                                usecs += q->qh->c_usecs;
-                       hw_p = &q->qh->hw_next;
+                       hw_p = &hw->hw_next;
                        q = &q->qh->qh_next;
                        break;
                // case Q_TYPE_FSTN:
@@ -108,22 +129,24 @@ periodic_usecs (struct ehci_hcd *ehci, unsigned frame, unsigned uframe)
                        /* for "save place" FSTNs, count the relevant INTR
                         * bandwidth from the previous frame
                         */
-                       if (q->fstn->hw_prev != EHCI_LIST_END) {
+                       if (q->fstn->hw_prev != EHCI_LIST_END(ehci)) {
                                ehci_dbg (ehci, "ignoring FSTN cost ...\n");
                        }
                        hw_p = &q->fstn->hw_next;
                        q = &q->fstn->fstn_next;
                        break;
                case Q_TYPE_ITD:
-                       usecs += q->itd->usecs [uframe];
+                       if (q->itd->hw_transaction[uframe])
+                               usecs += q->itd->stream->usecs;
                        hw_p = &q->itd->hw_next;
                        q = &q->itd->itd_next;
                        break;
                case Q_TYPE_SITD:
                        /* is it in the S-mask?  (count SPLIT, DATA) */
-                       if (q->sitd->hw_uframe & cpu_to_le32 (1 << uframe)) {
+                       if (q->sitd->hw_uframe & cpu_to_hc32(ehci,
+                                       1 << uframe)) {
                                if (q->sitd->hw_fullspeed_ep &
-                                               __constant_cpu_to_le32 (1<<31))
+                                               cpu_to_hc32(ehci, 1<<31))
                                        usecs += q->sitd->stream->usecs;
                                else    /* worst case for OUT start-split */
                                        usecs += HS_USECS_ISO (188);
@@ -131,7 +154,7 @@ periodic_usecs (struct ehci_hcd *ehci, unsigned frame, unsigned uframe)
 
                        /* ... C-mask?  (count CSPLIT, DATA) */
                        if (q->sitd->hw_uframe &
-                                       cpu_to_le32 (1 << (8 + uframe))) {
+                                       cpu_to_hc32(ehci, 1 << (8 + uframe))) {
                                /* worst case for IN complete-split */
                                usecs += q->sitd->stream->c_usecs;
                        }
@@ -163,6 +186,190 @@ static int same_tt (struct usb_device *dev1, struct usb_device *dev2)
                return 1;
 }
 
+#ifdef CONFIG_USB_EHCI_TT_NEWSCHED
+
+/* Which uframe does the low/fullspeed transfer start in?
+ *
+ * The parameter is the mask of ssplits in "H-frame" terms
+ * and this returns the transfer start uframe in "B-frame" terms,
+ * which allows both to match, e.g. a ssplit in "H-frame" uframe 0
+ * will cause a transfer in "B-frame" uframe 0.  "B-frames" lag
+ * "H-frames" by 1 uframe.  See the EHCI spec sec 4.5 and figure 4.7.
+ */
+static inline unsigned char tt_start_uframe(struct ehci_hcd *ehci, __hc32 mask)
+{
+       unsigned char smask = QH_SMASK & hc32_to_cpu(ehci, mask);
+       if (!smask) {
+               ehci_err(ehci, "invalid empty smask!\n");
+               /* uframe 7 can't have bw so this will indicate failure */
+               return 7;
+       }
+       return ffs(smask) - 1;
+}
+
+static const unsigned char
+max_tt_usecs[] = { 125, 125, 125, 125, 125, 125, 30, 0 };
+
+/* carryover low/fullspeed bandwidth that crosses uframe boundries */
+static inline void carryover_tt_bandwidth(unsigned short tt_usecs[8])
+{
+       int i;
+       for (i=0; i<7; i++) {
+               if (max_tt_usecs[i] < tt_usecs[i]) {
+                       tt_usecs[i+1] += tt_usecs[i] - max_tt_usecs[i];
+                       tt_usecs[i] = max_tt_usecs[i];
+               }
+       }
+}
+
+/* How many of the tt's periodic downstream 1000 usecs are allocated?
+ *
+ * While this measures the bandwidth in terms of usecs/uframe,
+ * the low/fullspeed bus has no notion of uframes, so any particular
+ * low/fullspeed transfer can "carry over" from one uframe to the next,
+ * since the TT just performs downstream transfers in sequence.
+ *
+ * For example two separate 100 usec transfers can start in the same uframe,
+ * and the second one would "carry over" 75 usecs into the next uframe.
+ */
+static void
+periodic_tt_usecs (
+       struct ehci_hcd *ehci,
+       struct usb_device *dev,
+       unsigned frame,
+       unsigned short tt_usecs[8]
+)
+{
+       __hc32                  *hw_p = &ehci->periodic [frame];
+       union ehci_shadow       *q = &ehci->pshadow [frame];
+       unsigned char           uf;
+
+       memset(tt_usecs, 0, 16);
+
+       while (q->ptr) {
+               switch (hc32_to_cpu(ehci, Q_NEXT_TYPE(ehci, *hw_p))) {
+               case Q_TYPE_ITD:
+                       hw_p = &q->itd->hw_next;
+                       q = &q->itd->itd_next;
+                       continue;
+               case Q_TYPE_QH:
+                       if (same_tt(dev, q->qh->dev)) {
+                               uf = tt_start_uframe(ehci, q->qh->hw->hw_info2);
+                               tt_usecs[uf] += q->qh->tt_usecs;
+                       }
+                       hw_p = &q->qh->hw->hw_next;
+                       q = &q->qh->qh_next;
+                       continue;
+               case Q_TYPE_SITD:
+                       if (same_tt(dev, q->sitd->urb->dev)) {
+                               uf = tt_start_uframe(ehci, q->sitd->hw_uframe);
+                               tt_usecs[uf] += q->sitd->stream->tt_usecs;
+                       }
+                       hw_p = &q->sitd->hw_next;
+                       q = &q->sitd->sitd_next;
+                       continue;
+               // case Q_TYPE_FSTN:
+               default:
+                       ehci_dbg(ehci, "ignoring periodic frame %d FSTN\n",
+                                       frame);
+                       hw_p = &q->fstn->hw_next;
+                       q = &q->fstn->fstn_next;
+               }
+       }
+
+       carryover_tt_bandwidth(tt_usecs);
+
+       if (max_tt_usecs[7] < tt_usecs[7])
+               ehci_err(ehci, "frame %d tt sched overrun: %d usecs\n",
+                       frame, tt_usecs[7] - max_tt_usecs[7]);
+}
+
+/*
+ * Return true if the device's tt's downstream bus is available for a
+ * periodic transfer of the specified length (usecs), starting at the
+ * specified frame/uframe.  Note that (as summarized in section 11.19
+ * of the usb 2.0 spec) TTs can buffer multiple transactions for each
+ * uframe.
+ *
+ * The uframe parameter is when the fullspeed/lowspeed transfer
+ * should be executed in "B-frame" terms, which is the same as the
+ * highspeed ssplit's uframe (which is in "H-frame" terms).  For example
+ * a ssplit in "H-frame" 0 causes a transfer in "B-frame" 0.
+ * See the EHCI spec sec 4.5 and fig 4.7.
+ *
+ * This checks if the full/lowspeed bus, at the specified starting uframe,
+ * has the specified bandwidth available, according to rules listed
+ * in USB 2.0 spec section 11.18.1 fig 11-60.
+ *
+ * This does not check if the transfer would exceed the max ssplit
+ * limit of 16, specified in USB 2.0 spec section 11.18.4 requirement #4,
+ * since proper scheduling limits ssplits to less than 16 per uframe.
+ */
+static int tt_available (
+       struct ehci_hcd         *ehci,
+       unsigned                period,
+       struct usb_device       *dev,
+       unsigned                frame,
+       unsigned                uframe,
+       u16                     usecs
+)
+{
+       if ((period == 0) || (uframe >= 7))     /* error */
+               return 0;
+
+       for (; frame < ehci->periodic_size; frame += period) {
+               unsigned short tt_usecs[8];
+
+               periodic_tt_usecs (ehci, dev, frame, tt_usecs);
+
+               ehci_vdbg(ehci, "tt frame %d check %d usecs start uframe %d in"
+                       " schedule %d/%d/%d/%d/%d/%d/%d/%d\n",
+                       frame, usecs, uframe,
+                       tt_usecs[0], tt_usecs[1], tt_usecs[2], tt_usecs[3],
+                       tt_usecs[4], tt_usecs[5], tt_usecs[6], tt_usecs[7]);
+
+               if (max_tt_usecs[uframe] <= tt_usecs[uframe]) {
+                       ehci_vdbg(ehci, "frame %d uframe %d fully scheduled\n",
+                               frame, uframe);
+                       return 0;
+               }
+
+               /* special case for isoc transfers larger than 125us:
+                * the first and each subsequent fully used uframe
+                * must be empty, so as to not illegally delay
+                * already scheduled transactions
+                */
+               if (125 < usecs) {
+                       int ufs = (usecs / 125);
+                       int i;
+                       for (i = uframe; i < (uframe + ufs) && i < 8; i++)
+                               if (0 < tt_usecs[i]) {
+                                       ehci_vdbg(ehci,
+                                               "multi-uframe xfer can't fit "
+                                               "in frame %d uframe %d\n",
+                                               frame, i);
+                                       return 0;
+                               }
+               }
+
+               tt_usecs[uframe] += usecs;
+
+               carryover_tt_bandwidth(tt_usecs);
+
+               /* fail if the carryover pushed bw past the last uframe's limit */
+               if (max_tt_usecs[7] < tt_usecs[7]) {
+                       ehci_vdbg(ehci,
+                               "tt unavailable usecs %d frame %d uframe %d\n",
+                               usecs, frame, uframe);
+                       return 0;
+               }
+       }
+
+       return 1;
+}
+
+#else
+
 /* return true iff the device's transaction translator is available
  * for a periodic transfer starting at the specified frame, using
  * all the uframes in the mask.
@@ -184,41 +391,44 @@ static int tt_no_collision (
         */
        for (; frame < ehci->periodic_size; frame += period) {
                union ehci_shadow       here;
-               __le32                  type;
+               __hc32                  type;
+               struct ehci_qh_hw       *hw;
 
                here = ehci->pshadow [frame];
-               type = Q_NEXT_TYPE (ehci->periodic [frame]);
+               type = Q_NEXT_TYPE(ehci, ehci->periodic [frame]);
                while (here.ptr) {
-                       switch (type) {
+                       switch (hc32_to_cpu(ehci, type)) {
                        case Q_TYPE_ITD:
-                               type = Q_NEXT_TYPE (here.itd->hw_next);
+                               type = Q_NEXT_TYPE(ehci, here.itd->hw_next);
                                here = here.itd->itd_next;
                                continue;
                        case Q_TYPE_QH:
+                               hw = here.qh->hw;
                                if (same_tt (dev, here.qh->dev)) {
                                        u32             mask;
 
-                                       mask = le32_to_cpu (here.qh->hw_info2);
+                                       mask = hc32_to_cpu(ehci,
+                                                       hw->hw_info2);
                                        /* "knows" no gap is needed */
                                        mask |= mask >> 8;
                                        if (mask & uf_mask)
                                                break;
                                }
-                               type = Q_NEXT_TYPE (here.qh->hw_next);
+                               type = Q_NEXT_TYPE(ehci, hw->hw_next);
                                here = here.qh->qh_next;
                                continue;
                        case Q_TYPE_SITD:
                                if (same_tt (dev, here.sitd->urb->dev)) {
                                        u16             mask;
 
-                                       mask = le32_to_cpu (here.sitd
+                                       mask = hc32_to_cpu(ehci, here.sitd
                                                                ->hw_uframe);
                                        /* FIXME assumes no gap for IN! */
                                        mask |= mask >> 8;
                                        if (mask & uf_mask)
                                                break;
                                }
-                               type = Q_NEXT_TYPE (here.sitd->hw_next);
+                               type = Q_NEXT_TYPE(ehci, here.sitd->hw_next);
                                here = here.sitd->sitd_next;
                                continue;
                        // case Q_TYPE_FSTN:
@@ -237,6 +447,8 @@ static int tt_no_collision (
        return 1;
 }
 
+#endif /* CONFIG_USB_EHCI_TT_NEWSCHED */
+
 /*-------------------------------------------------------------------------*/
 
 static int enable_periodic (struct ehci_hcd *ehci)
@@ -244,23 +456,27 @@ static int enable_periodic (struct ehci_hcd *ehci)
        u32     cmd;
        int     status;
 
+       if (ehci->periodic_sched++)
+               return 0;
+
        /* did clearing PSE did take effect yet?
         * takes effect only at frame boundaries...
         */
-       status = handshake (&ehci->regs->status, STS_PSS, 0, 9 * 125);
-       if (status != 0) {
-               ehci_to_hcd(ehci)->state = HC_STATE_HALT;
+       status = handshake_on_error_set_halt(ehci, &ehci->regs->status,
+                                            STS_PSS, 0, 9 * 125);
+       if (status)
                return status;
-       }
 
-       cmd = readl (&ehci->regs->command) | CMD_PSE;
-       writel (cmd, &ehci->regs->command);
+       cmd = ehci_readl(ehci, &ehci->regs->command) | CMD_PSE;
+       ehci_writel(ehci, cmd, &ehci->regs->command);
        /* posted write ... PSS happens later */
        ehci_to_hcd(ehci)->state = HC_STATE_RUNNING;
 
        /* make sure ehci_work scans these */
-       ehci->next_uframe = readl (&ehci->regs->frame_index)
-                               % (ehci->periodic_size << 3);
+       ehci->next_uframe = ehci_readl(ehci, &ehci->regs->frame_index)
+               % (ehci->periodic_size << 3);
+       if (unlikely(ehci->broken_periodic))
+               ehci->last_periodic_enable = ktime_get_real();
        return 0;
 }
 
@@ -269,17 +485,29 @@ static int disable_periodic (struct ehci_hcd *ehci)
        u32     cmd;
        int     status;
 
+       if (--ehci->periodic_sched)
+               return 0;
+
+       if (unlikely(ehci->broken_periodic)) {
+               /* delay experimentally determined */
+               ktime_t safe = ktime_add_us(ehci->last_periodic_enable, 1000);
+               ktime_t now = ktime_get_real();
+               s64 delay = ktime_us_delta(safe, now);
+
+               if (unlikely(delay > 0))
+                       udelay(delay);
+       }
+
        /* did setting PSE not take effect yet?
         * takes effect only at frame boundaries...
         */
-       status = handshake (&ehci->regs->status, STS_PSS, STS_PSS, 9 * 125);
-       if (status != 0) {
-               ehci_to_hcd(ehci)->state = HC_STATE_HALT;
+       status = handshake_on_error_set_halt(ehci, &ehci->regs->status,
+                                            STS_PSS, STS_PSS, 9 * 125);
+       if (status)
                return status;
-       }
 
-       cmd = readl (&ehci->regs->command) & ~CMD_PSE;
-       writel (cmd, &ehci->regs->command);
+       cmd = ehci_readl(ehci, &ehci->regs->command) & ~CMD_PSE;
+       ehci_writel(ehci, cmd, &ehci->regs->command);
        /* posted write ... */
 
        ehci->next_uframe = -1;
@@ -301,7 +529,8 @@ static int qh_link_periodic (struct ehci_hcd *ehci, struct ehci_qh *qh)
 
        dev_dbg (&qh->dev->dev,
                "link qh%d-%04x/%p start %d [%d/%d us]\n",
-               period, le32_to_cpup (&qh->hw_info2) & (QH_CMASK | QH_SMASK),
+               period, hc32_to_cpup(ehci, &qh->hw->hw_info2)
+                       & (QH_CMASK | QH_SMASK),
                qh, qh->start, qh->usecs, qh->c_usecs);
 
        /* high bandwidth, or otherwise every microframe */
@@ -309,18 +538,18 @@ static int qh_link_periodic (struct ehci_hcd *ehci, struct ehci_qh *qh)
                period = 1;
 
        for (i = qh->start; i < ehci->periodic_size; i += period) {
-               union ehci_shadow       *prev = &ehci->pshadow [i];
-               __le32                  *hw_p = &ehci->periodic [i];
+               union ehci_shadow       *prev = &ehci->pshadow[i];
+               __hc32                  *hw_p = &ehci->periodic[i];
                union ehci_shadow       here = *prev;
-               __le32                  type = 0;
+               __hc32                  type = 0;
 
                /* skip the iso nodes at list head */
                while (here.ptr) {
-                       type = Q_NEXT_TYPE (*hw_p);
-                       if (type == Q_TYPE_QH)
+                       type = Q_NEXT_TYPE(ehci, *hw_p);
+                       if (type == cpu_to_hc32(ehci, Q_TYPE_QH))
                                break;
-                       prev = periodic_next_shadow (prev, type);
-                       hw_p = &here.qh->hw_next;
+                       prev = periodic_next_shadow(ehci, prev, type);
+                       hw_p = shadow_next_periodic(ehci, &here, type);
                        here = *prev;
                }
 
@@ -331,20 +560,21 @@ static int qh_link_periodic (struct ehci_hcd *ehci, struct ehci_qh *qh)
                        if (qh->period > here.qh->period)
                                break;
                        prev = &here.qh->qh_next;
-                       hw_p = &here.qh->hw_next;
+                       hw_p = &here.qh->hw->hw_next;
                        here = *prev;
                }
                /* link in this qh, unless some earlier pass did that */
                if (qh != here.qh) {
                        qh->qh_next = here;
                        if (here.qh)
-                               qh->hw_next = *hw_p;
+                               qh->hw->hw_next = *hw_p;
                        wmb ();
                        prev->qh = qh;
-                       *hw_p = QH_NEXT (qh->qh_dma);
+                       *hw_p = QH_NEXT (ehci, qh->qh_dma);
                }
        }
        qh->qh_state = QH_STATE_LINKED;
+       qh->xacterrs = 0;
        qh_get (qh);
 
        /* update per-qh bandwidth for usbfs */
@@ -353,13 +583,10 @@ static int qh_link_periodic (struct ehci_hcd *ehci, struct ehci_qh *qh)
                : (qh->usecs * 8);
 
        /* maybe enable periodic schedule processing */
-       if (!ehci->periodic_sched++)
-               return enable_periodic (ehci);
-
-       return 0;
+       return enable_periodic(ehci);
 }
 
-static void qh_unlink_periodic (struct ehci_hcd *ehci, struct ehci_qh *qh)
+static int qh_unlink_periodic(struct ehci_hcd *ehci, struct ehci_qh *qh)
 {
        unsigned        i;
        unsigned        period;
@@ -369,7 +596,7 @@ static void qh_unlink_periodic (struct ehci_hcd *ehci, struct ehci_qh *qh)
        //   and this qh is active in the current uframe
        //   (and overlay token SplitXstate is false?)
        // THEN
-       //   qh->hw_info1 |= __constant_cpu_to_le32 (1 << 7 /* "ignore" */);
+       //   qh->hw_info1 |= cpu_to_hc32(1 << 7 /* "ignore" */);
 
        /* high bandwidth, or otherwise part of every microframe */
        if ((period = qh->period) == 0)
@@ -386,7 +613,7 @@ static void qh_unlink_periodic (struct ehci_hcd *ehci, struct ehci_qh *qh)
        dev_dbg (&qh->dev->dev,
                "unlink qh%d-%04x/%p start %d [%d/%d us]\n",
                qh->period,
-               le32_to_cpup (&qh->hw_info2) & (QH_CMASK | QH_SMASK),
+               hc32_to_cpup(ehci, &qh->hw->hw_info2) & (QH_CMASK | QH_SMASK),
                qh, qh->start, qh->usecs, qh->c_usecs);
 
        /* qh->qh_next still "live" to HC */
@@ -395,14 +622,24 @@ static void qh_unlink_periodic (struct ehci_hcd *ehci, struct ehci_qh *qh)
        qh_put (qh);
 
        /* maybe turn off periodic schedule */
-       ehci->periodic_sched--;
-       if (!ehci->periodic_sched)
-               (void) disable_periodic (ehci);
+       return disable_periodic(ehci);
 }
 
 static void intr_deschedule (struct ehci_hcd *ehci, struct ehci_qh *qh)
 {
-       unsigned        wait;
+       unsigned                wait;
+       struct ehci_qh_hw       *hw = qh->hw;
+       int                     rc;
+
+       /* If the QH isn't linked then there's nothing we can do
+        * unless we were called during a giveback, in which case
+        * qh_completions() has to deal with it.
+        */
+       if (qh->qh_state != QH_STATE_LINKED) {
+               if (qh->qh_state == QH_STATE_COMPLETING)
+                       qh->needs_rescan = 1;
+               return;
+       }
 
        qh_unlink_periodic (ehci, qh);
 
@@ -412,22 +649,40 @@ static void intr_deschedule (struct ehci_hcd *ehci, struct ehci_qh *qh)
         * active high speed queues may need bigger delays...
         */
        if (list_empty (&qh->qtd_list)
-                       || (__constant_cpu_to_le32 (QH_CMASK)
-                                       & qh->hw_info2) != 0)
+                       || (cpu_to_hc32(ehci, QH_CMASK)
+                                       & hw->hw_info2) != 0)
                wait = 2;
        else
                wait = 55;      /* worst case: 3 * 1024 */
 
        udelay (wait);
        qh->qh_state = QH_STATE_IDLE;
-       qh->hw_next = EHCI_LIST_END;
+       hw->hw_next = EHCI_LIST_END(ehci);
        wmb ();
+
+       qh_completions(ehci, qh);
+
+       /* reschedule QH iff another request is queued */
+       if (!list_empty(&qh->qtd_list) &&
+                       HC_IS_RUNNING(ehci_to_hcd(ehci)->state)) {
+               rc = qh_schedule(ehci, qh);
+
+               /* An error here likely indicates handshake failure
+                * or no space left in the schedule.  Neither fault
+                * should happen often ...
+                *
+                * FIXME kill the now-dysfunctional queued urbs
+                */
+               if (rc != 0)
+                       ehci_err(ehci, "can't reschedule qh %p, err %d\n",
+                                       qh, rc);
+       }
 }
 
 /*-------------------------------------------------------------------------*/
 
 static int check_period (
-       struct ehci_hcd *ehci, 
+       struct ehci_hcd *ehci,
        unsigned        frame,
        unsigned        uframe,
        unsigned        period,
@@ -443,7 +698,7 @@ static int check_period (
 
        /*
         * 80% periodic == 100 usec/uframe available
-        * convert "usecs we need" to "max already claimed" 
+        * convert "usecs we need" to "max already claimed"
         */
        usecs = 100 - usecs;
 
@@ -473,15 +728,15 @@ static int check_period (
 }
 
 static int check_intr_schedule (
-       struct ehci_hcd         *ehci, 
+       struct ehci_hcd         *ehci,
        unsigned                frame,
        unsigned                uframe,
        const struct ehci_qh    *qh,
-       __le32                  *c_maskp
+       __hc32                  *c_maskp
 )
 {
-       int             retval = -ENOSPC;
-       u8              mask;
+       int             retval = -ENOSPC;
+       u8              mask = 0;
 
        if (qh->c_usecs && uframe >= 6)         /* FSTN territory? */
                goto done;
@@ -494,15 +749,33 @@ static int check_intr_schedule (
                goto done;
        }
 
+#ifdef CONFIG_USB_EHCI_TT_NEWSCHED
+       if (tt_available (ehci, qh->period, qh->dev, frame, uframe,
+                               qh->tt_usecs)) {
+               unsigned i;
+
+               /* TODO : this may need FSTN for SSPLIT in uframe 5. */
+               for (i=uframe+1; i<8 && i<uframe+4; i++)
+                       if (!check_period (ehci, frame, i,
+                                               qh->period, qh->c_usecs))
+                               goto done;
+                       else
+                               mask |= 1 << i;
+
+               retval = 0;
+
+               *c_maskp = cpu_to_hc32(ehci, mask << 8);
+       }
+#else
        /* Make sure this tt's buffer is also available for CSPLITs.
         * We pessimize a bit; probably the typical full speed case
         * doesn't need the second CSPLIT.
-        * 
+        *
         * NOTE:  both SPLIT and CSPLIT could be checked in just
         * one smart pass...
         */
        mask = 0x03 << (uframe + qh->gap_uf);
-       *c_maskp = cpu_to_le32 (mask << 8);
+       *c_maskp = cpu_to_hc32(ehci, mask << 8);
 
        mask |= 1 << uframe;
        if (tt_no_collision (ehci, qh->period, qh->dev, frame, mask)) {
@@ -514,6 +787,7 @@ static int check_intr_schedule (
                        goto done;
                retval = 0;
        }
+#endif
 done:
        return retval;
 }
@@ -521,20 +795,21 @@ done:
 /* "first fit" scheduling policy used the first time through,
  * or when the previous schedule slot can't be re-used.
  */
-static int qh_schedule (struct ehci_hcd *ehci, struct ehci_qh *qh)
+static int qh_schedule(struct ehci_hcd *ehci, struct ehci_qh *qh)
 {
-       int             status;
+       int             status;
        unsigned        uframe;
-       __le32          c_mask;
+       __hc32          c_mask;
        unsigned        frame;          /* 0..(qh->period - 1), or NO_FRAME */
+       struct ehci_qh_hw       *hw = qh->hw;
 
        qh_refresh(ehci, qh);
-       qh->hw_next = EHCI_LIST_END;
+       hw->hw_next = EHCI_LIST_END(ehci);
        frame = qh->start;
 
        /* reuse the previous schedule slots, if we can */
        if (frame < qh->period) {
-               uframe = ffs (le32_to_cpup (&qh->hw_info2) & QH_SMASK);
+               uframe = ffs(hc32_to_cpup(ehci, &hw->hw_info2) & QH_SMASK);
                status = check_intr_schedule (ehci, frame, --uframe,
                                qh, &c_mask);
        } else {
@@ -549,8 +824,10 @@ static int qh_schedule (struct ehci_hcd *ehci, struct ehci_qh *qh)
        if (status) {
                /* "normal" case, uframing flexible except with splits */
                if (qh->period) {
-                       frame = qh->period - 1;
-                       do {
+                       int             i;
+
+                       for (i = qh->period; status && i > 0; --i) {
+                               frame = ++ehci->random_frame % qh->period;
                                for (uframe = 0; uframe < 8; uframe++) {
                                        status = check_intr_schedule (ehci,
                                                        frame, uframe, qh,
@@ -558,7 +835,7 @@ static int qh_schedule (struct ehci_hcd *ehci, struct ehci_qh *qh)
                                        if (status == 0)
                                                break;
                                }
-                       } while (status && frame--);
+                       }
 
                /* qh->period == 0 means every uframe */
                } else {
@@ -570,23 +847,22 @@ static int qh_schedule (struct ehci_hcd *ehci, struct ehci_qh *qh)
                qh->start = frame;
 
                /* reset S-frame and (maybe) C-frame masks */
-               qh->hw_info2 &= __constant_cpu_to_le32(~(QH_CMASK | QH_SMASK));
-               qh->hw_info2 |= qh->period
-                       ? cpu_to_le32 (1 << uframe)
-                       : __constant_cpu_to_le32 (QH_SMASK);
-               qh->hw_info2 |= c_mask;
+               hw->hw_info2 &= cpu_to_hc32(ehci, ~(QH_CMASK | QH_SMASK));
+               hw->hw_info2 |= qh->period
+                       ? cpu_to_hc32(ehci, 1 << uframe)
+                       : cpu_to_hc32(ehci, QH_SMASK);
+               hw->hw_info2 |= c_mask;
        } else
                ehci_dbg (ehci, "reused qh %p schedule\n", qh);
 
        /* stuff into the periodic schedule */
-       status = qh_link_periodic (ehci, qh);
+       status = qh_link_periodic (ehci, qh);
 done:
        return status;
 }
 
 static int intr_submit (
        struct ehci_hcd         *ehci,
-       struct usb_host_endpoint *ep,
        struct urb              *urb,
        struct list_head        *qtd_list,
        gfp_t                   mem_flags
@@ -594,23 +870,26 @@ static int intr_submit (
        unsigned                epnum;
        unsigned long           flags;
        struct ehci_qh          *qh;
-       int                     status = 0;
+       int                     status;
        struct list_head        empty;
 
        /* get endpoint and transfer/schedule data */
-       epnum = ep->desc.bEndpointAddress;
+       epnum = urb->ep->desc.bEndpointAddress;
 
        spin_lock_irqsave (&ehci->lock, flags);
 
        if (unlikely(!test_bit(HCD_FLAG_HW_ACCESSIBLE,
-                              &ehci_to_hcd(ehci)->flags))) {
+                       &ehci_to_hcd(ehci)->flags))) {
                status = -ESHUTDOWN;
-               goto done;
+               goto done_not_linked;
        }
+       status = usb_hcd_link_urb_to_ep(ehci_to_hcd(ehci), urb);
+       if (unlikely(status))
+               goto done_not_linked;
 
        /* get qh and force any scheduling errors */
        INIT_LIST_HEAD (&empty);
-       qh = qh_append_tds (ehci, urb, &empty, epnum, &ep->hcpriv);
+       qh = qh_append_tds(ehci, urb, &empty, epnum, &urb->ep->hcpriv);
        if (qh == NULL) {
                status = -ENOMEM;
                goto done;
@@ -621,13 +900,16 @@ static int intr_submit (
        }
 
        /* then queue the urb's tds to the qh */
-       qh = qh_append_tds (ehci, urb, qtd_list, epnum, &ep->hcpriv);
+       qh = qh_append_tds(ehci, urb, qtd_list, epnum, &urb->ep->hcpriv);
        BUG_ON (qh == NULL);
 
        /* ... update usbfs periodic stats */
        ehci_to_hcd(ehci)->self.bandwidth_int_reqs++;
 
 done:
+       if (unlikely(status))
+               usb_hcd_unlink_urb_from_ep(ehci_to_hcd(ehci), urb);
+done_not_linked:
        spin_unlock_irqrestore (&ehci->lock, flags);
        if (status)
                qtd_list_free (ehci, urb, qtd_list);
@@ -693,20 +975,21 @@ iso_stream_init (
                buf1 |= maxp;
                maxp *= multi;
 
-               stream->buf0 = cpu_to_le32 ((epnum << 8) | dev->devnum);
-               stream->buf1 = cpu_to_le32 (buf1);
-               stream->buf2 = cpu_to_le32 (multi);
+               stream->buf0 = cpu_to_hc32(ehci, (epnum << 8) | dev->devnum);
+               stream->buf1 = cpu_to_hc32(ehci, buf1);
+               stream->buf2 = cpu_to_hc32(ehci, multi);
 
                /* usbfs wants to report the average usecs per frame tied up
                 * when transfers on this endpoint are scheduled ...
                 */
                stream->usecs = HS_USECS_ISO (maxp);
                bandwidth = stream->usecs * 8;
-               bandwidth /= 1 << (interval - 1);
+               bandwidth /= interval;
 
        } else {
                u32             addr;
                int             think_time;
+               int             hs_transfers;
 
                addr = dev->ttport << 24;
                if (!ehci_is_TDI(ehci)
@@ -719,6 +1002,7 @@ iso_stream_init (
                think_time = dev->tt ? dev->tt->think_time : 0;
                stream->tt_usecs = NS_TO_US (think_time + usb_calc_bus_time (
                                dev->speed, is_input, 1, maxp));
+               hs_transfers = max (1u, (maxp + 187) / 188);
                if (is_input) {
                        u32     tmp;
 
@@ -727,17 +1011,16 @@ iso_stream_init (
                        stream->usecs = HS_USECS_ISO (1);
                        stream->raw_mask = 1;
 
-                       /* pessimistic c-mask */
-                       tmp = usb_calc_bus_time (USB_SPEED_FULL, 1, 0, maxp)
-                                       / (125 * 1000);
-                       stream->raw_mask |= 3 << (tmp + 9);
+                       /* c-mask as specified in USB 2.0 11.18.4 3.c */
+                       tmp = (1 << (hs_transfers + 2)) - 1;
+                       stream->raw_mask |= tmp << (8 + 2);
                } else
-                       stream->raw_mask = smask_out [maxp / 188];
+                       stream->raw_mask = smask_out [hs_transfers - 1];
                bandwidth = stream->usecs + stream->c_usecs;
-               bandwidth /= 1 << (interval + 2);
+               bandwidth /= interval << 3;
 
                /* stream->splits gets created from raw_mask later */
-               stream->address = cpu_to_le32 (addr);
+               stream->address = cpu_to_hc32(ehci, addr);
        }
        stream->bandwidth = bandwidth;
 
@@ -787,7 +1070,8 @@ iso_stream_put(struct ehci_hcd *ehci, struct ehci_iso_stream *stream)
 
                is_in = (stream->bEndpointAddress & USB_DIR_IN) ? 0x10 : 0;
                stream->bEndpointAddress &= 0x0f;
-               stream->ep->hcpriv = NULL;
+               if (stream->ep)
+                       stream->ep->hcpriv = NULL;
 
                if (stream->rescheduled) {
                        ehci_info (ehci, "ep%d%s-iso rescheduled "
@@ -863,16 +1147,16 @@ iso_sched_alloc (unsigned packets, gfp_t mem_flags)
        int                     size = sizeof *iso_sched;
 
        size += packets * sizeof (struct ehci_iso_packet);
-       iso_sched = kmalloc (size, mem_flags);
+       iso_sched = kzalloc(size, mem_flags);
        if (likely (iso_sched != NULL)) {
-               memset(iso_sched, 0, size);
                INIT_LIST_HEAD (&iso_sched->td_list);
        }
        return iso_sched;
 }
 
 static inline void
-itd_sched_init (
+itd_sched_init(
+       struct ehci_hcd         *ehci,
        struct ehci_iso_sched   *iso_sched,
        struct ehci_iso_stream  *stream,
        struct urb              *urb
@@ -902,7 +1186,7 @@ itd_sched_init (
                                && !(urb->transfer_flags & URB_NO_INTERRUPT))
                        trans |= EHCI_ITD_IOC;
                trans |= length << 16;
-               uframe->transaction = cpu_to_le32 (trans);
+               uframe->transaction = cpu_to_hc32(ehci, trans);
 
                /* might need to cross a buffer page within a uframe */
                uframe->bufp = (buf & ~(u64)0x0fff);
@@ -944,7 +1228,7 @@ itd_urb_transaction (
        if (unlikely (sched == NULL))
                return -ENOMEM;
 
-       itd_sched_init (sched, stream, urb);
+       itd_sched_init(ehci, sched, stream, urb);
 
        if (urb->interval < 8)
                num_itds = 1 + (sched->span + 7) / 8;
@@ -962,24 +1246,21 @@ itd_urb_transaction (
                /* prefer previously-allocated itds */
                if (likely (!list_empty(&stream->free_list))) {
                        itd = list_entry (stream->free_list.prev,
-                                        struct ehci_itd, itd_list);
+                                       struct ehci_itd, itd_list);
                        list_del (&itd->itd_list);
                        itd_dma = itd->itd_dma;
-               } else
-                       itd = NULL;
-
-               if (!itd) {
+               } else {
                        spin_unlock_irqrestore (&ehci->lock, flags);
                        itd = dma_pool_alloc (ehci->itd_pool, mem_flags,
                                        &itd_dma);
                        spin_lock_irqsave (&ehci->lock, flags);
+                       if (!itd) {
+                               iso_sched_free(stream, sched);
+                               spin_unlock_irqrestore(&ehci->lock, flags);
+                               return -ENOMEM;
+                       }
                }
 
-               if (unlikely (NULL == itd)) {
-                       iso_sched_free (stream, sched);
-                       spin_unlock_irqrestore (&ehci->lock, flags);
-                       return -ENOMEM;
-               }
                memset (itd, 0, sizeof *itd);
                itd->itd_dma = itd_dma;
                list_add (&itd->itd_list, &sched->td_list);
@@ -1047,12 +1328,21 @@ sitd_slot_ok (
                frame = uframe >> 3;
                uf = uframe & 7;
 
+#ifdef CONFIG_USB_EHCI_TT_NEWSCHED
+               /* The tt's fullspeed bus bandwidth must be available.
+                * tt_available scheduling guarantees 10+% for control/bulk.
+                */
+               if (!tt_available (ehci, period_uframes << 3,
+                               stream->udev, frame, uf, stream->tt_usecs))
+                       return 0;
+#else
                /* tt must be idle for start(s), any gap, and csplit.
                 * assume scheduling slop leaves 10+% for control/bulk.
                 */
                if (!tt_no_collision (ehci, period_uframes << 3,
                                stream->udev, frame, mask))
                        return 0;
+#endif
 
                /* check starts (OUT uses more than one) */
                max_used = 100 - stream->usecs;
@@ -1080,7 +1370,7 @@ sitd_slot_ok (
                uframe += period_uframes;
        } while (uframe < mod);
 
-       stream->splits = cpu_to_le32(stream->raw_mask << (uframe & 7));
+       stream->splits = cpu_to_hc32(ehci, stream->raw_mask << (uframe & 7));
        return 1;
 }
 
@@ -1122,23 +1412,37 @@ iso_stream_schedule (
                goto fail;
        }
 
-       now = readl (&ehci->regs->frame_index) % mod;
+       period = urb->interval;
+       if (!stream->highspeed)
+               period <<= 3;
+
+       now = ehci_readl(ehci, &ehci->regs->frame_index) % mod;
 
        /* when's the last uframe this urb could start? */
        max = now + mod;
 
-       /* typical case: reuse current schedule. stream is still active,
-        * and no gaps from host falling behind (irq delays etc)
+       /* Typical case: reuse current schedule, stream is still active.
+        * Hopefully there are no gaps from the host falling behind
+        * (irq delays etc), but if there are we'll take the next
+        * slot in the schedule, implicitly assuming URB_ISO_ASAP.
         */
        if (likely (!list_empty (&stream->td_list))) {
                start = stream->next_uframe;
                if (start < now)
                        start += mod;
-               if (likely ((start + sched->span) < max))
-                       goto ready;
-               /* else fell behind; someday, try to reschedule */
-               status = -EL2NSYNC;
-               goto fail;
+
+               /* Fell behind (by up to twice the slop amount)? */
+               if (start >= max - 2 * 8 * SCHEDULE_SLOP)
+                       start += period * DIV_ROUND_UP(
+                                       max - start, period) - mod;
+
+               /* Tried to schedule too far into the future? */
+               if (unlikely((start + sched->span) >= max)) {
+                       status = -EFBIG;
+                       goto fail;
+               }
+               stream->next_uframe = start;
+               goto ready;
        }
 
        /* need to schedule; when's the next (u)frame we could start?
@@ -1153,10 +1457,6 @@ iso_stream_schedule (
 
        /* NOTE:  assumes URB_ISO_ASAP, to limit complexity/bugs */
 
-       period = urb->interval;
-       if (!stream->highspeed)
-               period <<= 3;
-
        /* find a uframe slot with enough bandwidth */
        for (; start < (stream->next_uframe + period); start++) {
                int             enough_space;
@@ -1201,12 +1501,13 @@ ready:
 /*-------------------------------------------------------------------------*/
 
 static inline void
-itd_init (struct ehci_iso_stream *stream, struct ehci_itd *itd)
+itd_init(struct ehci_hcd *ehci, struct ehci_iso_stream *stream,
+               struct ehci_itd *itd)
 {
        int i;
 
        /* it's been recently zeroed */
-       itd->hw_next = EHCI_LIST_END;
+       itd->hw_next = EHCI_LIST_END(ehci);
        itd->hw_bufp [0] = stream->buf0;
        itd->hw_bufp [1] = stream->buf1;
        itd->hw_bufp [2] = stream->buf2;
@@ -1218,7 +1519,8 @@ itd_init (struct ehci_iso_stream *stream, struct ehci_itd *itd)
 }
 
 static inline void
-itd_patch (
+itd_patch(
+       struct ehci_hcd         *ehci,
        struct ehci_itd         *itd,
        struct ehci_iso_sched   *iso_sched,
        unsigned                index,
@@ -1233,17 +1535,18 @@ itd_patch (
        uframe &= 0x07;
        itd->index [uframe] = index;
 
-       itd->hw_transaction [uframe] = uf->transaction;
-       itd->hw_transaction [uframe] |= cpu_to_le32 (pg << 12);
-       itd->hw_bufp [pg] |= cpu_to_le32 (uf->bufp & ~(u32)0);
-       itd->hw_bufp_hi [pg] |= cpu_to_le32 ((u32)(uf->bufp >> 32));
+       itd->hw_transaction[uframe] = uf->transaction;
+       itd->hw_transaction[uframe] |= cpu_to_hc32(ehci, pg << 12);
+       itd->hw_bufp[pg] |= cpu_to_hc32(ehci, uf->bufp & ~(u32)0);
+       itd->hw_bufp_hi[pg] |= cpu_to_hc32(ehci, (u32)(uf->bufp >> 32));
 
        /* iso_frame_desc[].offset must be strictly increasing */
        if (unlikely (uf->cross)) {
                u64     bufp = uf->bufp + 4096;
+
                itd->pg = ++pg;
-               itd->hw_bufp [pg] |= cpu_to_le32 (bufp & ~(u32)0);
-               itd->hw_bufp_hi [pg] |= cpu_to_le32 ((u32)(bufp >> 32));
+               itd->hw_bufp[pg] |= cpu_to_hc32(ehci, bufp & ~(u32)0);
+               itd->hw_bufp_hi[pg] |= cpu_to_hc32(ehci, (u32)(bufp >> 32));
        }
 }
 
@@ -1256,7 +1559,7 @@ itd_link (struct ehci_hcd *ehci, unsigned frame, struct ehci_itd *itd)
        ehci->pshadow [frame].itd = itd;
        itd->frame = frame;
        wmb ();
-       ehci->periodic [frame] = cpu_to_le32 (itd->itd_dma) | Q_TYPE_ITD;
+       ehci->periodic[frame] = cpu_to_hc32(ehci, itd->itd_dma | Q_TYPE_ITD);
 }
 
 /* fit urb's itds into the selected schedule slot; activate as needed */
@@ -1300,15 +1603,14 @@ itd_link_urb (
                                        struct ehci_itd, itd_list);
                        list_move_tail (&itd->itd_list, &stream->td_list);
                        itd->stream = iso_stream_get (stream);
-                       itd->urb = usb_get_urb (urb);
-                       itd_init (stream, itd);
+                       itd->urb = urb;
+                       itd_init (ehci, stream, itd);
                }
 
                uframe = next_uframe & 0x07;
                frame = next_uframe >> 3;
 
-               itd->usecs [uframe] = stream->usecs;
-               itd_patch (itd, iso_sched, packet, uframe);
+               itd_patch(ehci, itd, iso_sched, packet, uframe);
 
                next_uframe += stream->interval;
                stream->depth += stream->interval;
@@ -1329,18 +1631,25 @@ itd_link_urb (
        urb->hcpriv = NULL;
 
        timer_action (ehci, TIMER_IO_WATCHDOG);
-       if (unlikely (!ehci->periodic_sched++))
-               return enable_periodic (ehci);
-       return 0;
+       return enable_periodic(ehci);
 }
 
 #define        ISO_ERRS (EHCI_ISOC_BUF_ERR | EHCI_ISOC_BABBLE | EHCI_ISOC_XACTERR)
 
+/* Process and recycle a completed ITD.  Return true iff its urb completed,
+ * and hence its completion callback probably added things to the hardware
+ * schedule.
+ *
+ * Note that we carefully avoid recycling this descriptor until after any
+ * completion callback runs, so that it won't be reused quickly.  That is,
+ * assuming (a) no more than two urbs per frame on this endpoint, and also
+ * (b) only this endpoint's completions submit URBs.  It seems some silicon
+ * corrupts things if you reuse completed descriptors very quickly...
+ */
 static unsigned
 itd_complete (
        struct ehci_hcd *ehci,
-       struct ehci_itd *itd,
-       struct pt_regs  *regs
+       struct ehci_itd *itd
 ) {
        struct urb                              *urb = itd->urb;
        struct usb_iso_packet_descriptor        *desc;
@@ -1349,6 +1658,7 @@ itd_complete (
        int                                     urb_index = -1;
        struct ehci_iso_stream                  *stream = itd->stream;
        struct usb_device                       *dev;
+       unsigned                                retval = false;
 
        /* for each uframe with a packet */
        for (uframe = 0; uframe < 8; uframe++) {
@@ -1357,7 +1667,7 @@ itd_complete (
                urb_index = itd->index[uframe];
                desc = &urb->iso_frame_desc [urb_index];
 
-               t = le32_to_cpup (&itd->hw_transaction [uframe]);
+               t = hc32_to_cpup(ehci, &itd->hw_transaction [uframe]);
                itd->hw_transaction [uframe] = 0;
                stream->depth -= stream->interval;
 
@@ -1374,41 +1684,38 @@ itd_complete (
                                desc->status = -EPROTO;
 
                        /* HC need not update length with this error */
-                       if (!(t & EHCI_ISOC_BABBLE))
-                               desc->actual_length = EHCI_ITD_LENGTH (t);
+                       if (!(t & EHCI_ISOC_BABBLE)) {
+                               desc->actual_length = EHCI_ITD_LENGTH(t);
+                               urb->actual_length += desc->actual_length;
+                       }
                } else if (likely ((t & EHCI_ISOC_ACTIVE) == 0)) {
                        desc->status = 0;
-                       desc->actual_length = EHCI_ITD_LENGTH (t);
+                       desc->actual_length = EHCI_ITD_LENGTH(t);
+                       urb->actual_length += desc->actual_length;
+               } else {
+                       /* URB was too late */
+                       desc->status = -EXDEV;
                }
        }
 
-       usb_put_urb (urb);
-       itd->urb = NULL;
-       itd->stream = NULL;
-       list_move (&itd->itd_list, &stream->free_list);
-       iso_stream_put (ehci, stream);
-
        /* handle completion now? */
        if (likely ((urb_index + 1) != urb->number_of_packets))
-               return 0;
+               goto done;
 
        /* ASSERT: it's really the last itd for this urb
        list_for_each_entry (itd, &stream->td_list, itd_list)
                BUG_ON (itd->urb == urb);
         */
 
-       /* give urb back to the driver ... can be out-of-order */
-       dev = usb_get_dev (urb->dev);
-       ehci_urb_done (ehci, urb, regs);
+       /* give urb back to the driver; completion often (re)submits */
+       dev = urb->dev;
+       ehci_urb_done(ehci, urb, 0);
+       retval = true;
        urb = NULL;
-
-       /* defer stopping schedule; completion can submit */
-       ehci->periodic_sched--;
-       if (unlikely (!ehci->periodic_sched))
-               (void) disable_periodic (ehci);
+       (void) disable_periodic(ehci);
        ehci_to_hcd(ehci)->self.bandwidth_isoc_reqs--;
 
-       if (unlikely (list_empty (&stream->td_list))) {
+       if (unlikely(list_is_singular(&stream->td_list))) {
                ehci_to_hcd(ehci)->self.bandwidth_allocated
                                -= stream->bandwidth;
                ehci_vdbg (ehci,
@@ -1417,9 +1724,28 @@ itd_complete (
                        (stream->bEndpointAddress & USB_DIR_IN) ? "in" : "out");
        }
        iso_stream_put (ehci, stream);
-       usb_put_dev (dev);
 
-       return 1;
+done:
+       itd->urb = NULL;
+       if (ehci->clock_frame != itd->frame || itd->index[7] != -1) {
+               /* OK to recycle this ITD now. */
+               itd->stream = NULL;
+               list_move(&itd->itd_list, &stream->free_list);
+               iso_stream_put(ehci, stream);
+       } else {
+               /* HW might remember this ITD, so we can't recycle it yet.
+                * Move it to a safe place until a new frame starts.
+                */
+               list_move(&itd->itd_list, &ehci->cached_itd_list);
+               if (stream->refcount == 2) {
+                       /* If iso_stream_put() were called here, stream
+                        * would be freed.  Instead, just prevent reuse.
+                        */
+                       stream->ep->hcpriv = NULL;
+                       stream->ep = NULL;
+               }
+       }
+       return retval;
 }
 
 /*-------------------------------------------------------------------------*/
@@ -1446,7 +1772,7 @@ static int itd_submit (struct ehci_hcd *ehci, struct urb *urb,
 #ifdef EHCI_URB_TRACE
        ehci_dbg (ehci,
                "%s %s urb %p ep%d%s len %d, %d pkts %d uframes [%p]\n",
-               __FUNCTION__, urb->dev->devpath, urb,
+               __func__, urb->dev->devpath, urb,
                usb_pipeendpoint (urb->pipe),
                usb_pipein (urb->pipe) ? "in" : "out",
                urb->transfer_buffer_length,
@@ -1464,12 +1790,19 @@ static int itd_submit (struct ehci_hcd *ehci, struct urb *urb,
        /* schedule ... need to lock */
        spin_lock_irqsave (&ehci->lock, flags);
        if (unlikely(!test_bit(HCD_FLAG_HW_ACCESSIBLE,
-                              &ehci_to_hcd(ehci)->flags)))
+                              &ehci_to_hcd(ehci)->flags))) {
                status = -ESHUTDOWN;
-       else
-               status = iso_stream_schedule (ehci, urb, stream);
-       if (likely (status == 0))
+               goto done_not_linked;
+       }
+       status = usb_hcd_link_urb_to_ep(ehci_to_hcd(ehci), urb);
+       if (unlikely(status))
+               goto done_not_linked;
+       status = iso_stream_schedule(ehci, urb, stream);
+       if (likely (status == 0))
                itd_link_urb (ehci, urb, ehci->periodic_size << 3, stream);
+       else
+               usb_hcd_unlink_urb_from_ep(ehci_to_hcd(ehci), urb);
+done_not_linked:
        spin_unlock_irqrestore (&ehci->lock, flags);
 
 done:
@@ -1478,8 +1811,6 @@ done:
        return status;
 }
 
-#ifdef CONFIG_USB_EHCI_SPLIT_ISO
-
 /*-------------------------------------------------------------------------*/
 
 /*
@@ -1488,7 +1819,8 @@ done:
  */
 
 static inline void
-sitd_sched_init (
+sitd_sched_init(
+       struct ehci_hcd         *ehci,
        struct ehci_iso_sched   *iso_sched,
        struct ehci_iso_stream  *stream,
        struct urb              *urb
@@ -1517,7 +1849,7 @@ sitd_sched_init (
                                && !(urb->transfer_flags & URB_NO_INTERRUPT))
                        trans |= SITD_IOC;
                trans |= length << 16;
-               packet->transaction = cpu_to_le32 (trans);
+               packet->transaction = cpu_to_hc32(ehci, trans);
 
                /* might need to cross a buffer page within a td */
                packet->bufp = buf;
@@ -1525,7 +1857,7 @@ sitd_sched_init (
                if (packet->buf1 != (buf & ~(u64)0x0fff))
                        packet->cross = 1;
 
-               /* OUT uses multiple start-splits */ 
+               /* OUT uses multiple start-splits */
                if (stream->bEndpointAddress & USB_DIR_IN)
                        continue;
                length = (length + 187) / 188;
@@ -1553,7 +1885,7 @@ sitd_urb_transaction (
        if (iso_sched == NULL)
                return -ENOMEM;
 
-       sitd_sched_init (iso_sched, stream, urb);
+       sitd_sched_init(ehci, iso_sched, stream, urb);
 
        /* allocate/init sITDs */
        spin_lock_irqsave (&ehci->lock, flags);
@@ -1574,21 +1906,18 @@ sitd_urb_transaction (
                                         struct ehci_sitd, sitd_list);
                        list_del (&sitd->sitd_list);
                        sitd_dma = sitd->sitd_dma;
-               } else
-                       sitd = NULL;
-
-               if (!sitd) {
+               } else {
                        spin_unlock_irqrestore (&ehci->lock, flags);
                        sitd = dma_pool_alloc (ehci->sitd_pool, mem_flags,
                                        &sitd_dma);
                        spin_lock_irqsave (&ehci->lock, flags);
+                       if (!sitd) {
+                               iso_sched_free(stream, iso_sched);
+                               spin_unlock_irqrestore(&ehci->lock, flags);
+                               return -ENOMEM;
+                       }
                }
 
-               if (!sitd) {
-                       iso_sched_free (stream, iso_sched);
-                       spin_unlock_irqrestore (&ehci->lock, flags);
-                       return -ENOMEM;
-               }
                memset (sitd, 0, sizeof *sitd);
                sitd->sitd_dma = sitd_dma;
                list_add (&sitd->sitd_list, &iso_sched->td_list);
@@ -1605,7 +1934,8 @@ sitd_urb_transaction (
 /*-------------------------------------------------------------------------*/
 
 static inline void
-sitd_patch (
+sitd_patch(
+       struct ehci_hcd         *ehci,
        struct ehci_iso_stream  *stream,
        struct ehci_sitd        *sitd,
        struct ehci_iso_sched   *iso_sched,
@@ -1615,20 +1945,20 @@ sitd_patch (
        struct ehci_iso_packet  *uf = &iso_sched->packet [index];
        u64                     bufp = uf->bufp;
 
-       sitd->hw_next = EHCI_LIST_END;
+       sitd->hw_next = EHCI_LIST_END(ehci);
        sitd->hw_fullspeed_ep = stream->address;
        sitd->hw_uframe = stream->splits;
        sitd->hw_results = uf->transaction;
-       sitd->hw_backpointer = EHCI_LIST_END;
+       sitd->hw_backpointer = EHCI_LIST_END(ehci);
 
        bufp = uf->bufp;
-       sitd->hw_buf [0] = cpu_to_le32 (bufp);
-       sitd->hw_buf_hi [0] = cpu_to_le32 (bufp >> 32);
+       sitd->hw_buf[0] = cpu_to_hc32(ehci, bufp);
+       sitd->hw_buf_hi[0] = cpu_to_hc32(ehci, bufp >> 32);
 
-       sitd->hw_buf [1] = cpu_to_le32 (uf->buf1);
+       sitd->hw_buf[1] = cpu_to_hc32(ehci, uf->buf1);
        if (uf->cross)
                bufp += 4096;
-       sitd->hw_buf_hi [1] = cpu_to_le32 (bufp >> 32);
+       sitd->hw_buf_hi[1] = cpu_to_hc32(ehci, bufp >> 32);
        sitd->index = index;
 }
 
@@ -1641,7 +1971,7 @@ sitd_link (struct ehci_hcd *ehci, unsigned frame, struct ehci_sitd *sitd)
        ehci->pshadow [frame].sitd = sitd;
        sitd->frame = frame;
        wmb ();
-       ehci->periodic [frame] = cpu_to_le32 (sitd->sitd_dma) | Q_TYPE_SITD;
+       ehci->periodic[frame] = cpu_to_hc32(ehci, sitd->sitd_dma | Q_TYPE_SITD);
 }
 
 /* fit urb's sitds into the selected schedule slot; activate as needed */
@@ -1669,7 +1999,7 @@ sitd_link_urb (
                        urb->dev->devpath, stream->bEndpointAddress & 0x0f,
                        (stream->bEndpointAddress & USB_DIR_IN) ? "in" : "out",
                        (next_uframe >> 3) % ehci->periodic_size,
-                       stream->interval, le32_to_cpu (stream->splits));
+                       stream->interval, hc32_to_cpu(ehci, stream->splits));
                stream->start = jiffies;
        }
        ehci_to_hcd(ehci)->self.bandwidth_isoc_reqs++;
@@ -1688,9 +2018,9 @@ sitd_link_urb (
                                struct ehci_sitd, sitd_list);
                list_move_tail (&sitd->sitd_list, &stream->td_list);
                sitd->stream = iso_stream_get (stream);
-               sitd->urb = usb_get_urb (urb);
+               sitd->urb = urb;
 
-               sitd_patch (stream, sitd, sched, packet);
+               sitd_patch(ehci, stream, sitd, sched, packet);
                sitd_link (ehci, (next_uframe >> 3) % ehci->periodic_size,
                                sitd);
 
@@ -1704,21 +2034,28 @@ sitd_link_urb (
        urb->hcpriv = NULL;
 
        timer_action (ehci, TIMER_IO_WATCHDOG);
-       if (!ehci->periodic_sched++)
-               return enable_periodic (ehci);
-       return 0;
+       return enable_periodic(ehci);
 }
 
 /*-------------------------------------------------------------------------*/
 
 #define        SITD_ERRS (SITD_STS_ERR | SITD_STS_DBE | SITD_STS_BABBLE \
-                               | SITD_STS_XACT | SITD_STS_MMF)
+                               | SITD_STS_XACT | SITD_STS_MMF)
 
+/* Process and recycle a completed SITD.  Return true iff its urb completed,
+ * and hence its completion callback probably added things to the hardware
+ * schedule.
+ *
+ * Note that we carefully avoid recycling this descriptor until after any
+ * completion callback runs, so that it won't be reused quickly.  That is,
+ * assuming (a) no more than two urbs per frame on this endpoint, and also
+ * (b) only this endpoint's completions submit URBs.  It seems some silicon
+ * corrupts things if you reuse completed descriptors very quickly...
+ */
 static unsigned
 sitd_complete (
        struct ehci_hcd         *ehci,
-       struct ehci_sitd        *sitd,
-       struct pt_regs          *regs
+       struct ehci_sitd        *sitd
 ) {
        struct urb                              *urb = sitd->urb;
        struct usb_iso_packet_descriptor        *desc;
@@ -1726,10 +2063,11 @@ sitd_complete (
        int                                     urb_index = -1;
        struct ehci_iso_stream                  *stream = sitd->stream;
        struct usb_device                       *dev;
+       unsigned                                retval = false;
 
        urb_index = sitd->index;
        desc = &urb->iso_frame_desc [urb_index];
-       t = le32_to_cpup (&sitd->hw_results);
+       t = hc32_to_cpup(ehci, &sitd->hw_results);
 
        /* report transfer status */
        if (t & SITD_ERRS) {
@@ -1744,37 +2082,29 @@ sitd_complete (
                        desc->status = -EPROTO;
        } else {
                desc->status = 0;
-               desc->actual_length = desc->length - SITD_LENGTH (t);
+               desc->actual_length = desc->length - SITD_LENGTH(t);
+               urb->actual_length += desc->actual_length;
        }
-
-       usb_put_urb (urb);
-       sitd->urb = NULL;
-       sitd->stream = NULL;
-       list_move (&sitd->sitd_list, &stream->free_list);
        stream->depth -= stream->interval << 3;
-       iso_stream_put (ehci, stream);
 
        /* handle completion now? */
        if ((urb_index + 1) != urb->number_of_packets)
-               return 0;
+               goto done;
 
        /* ASSERT: it's really the last sitd for this urb
        list_for_each_entry (sitd, &stream->td_list, sitd_list)
                BUG_ON (sitd->urb == urb);
         */
 
-       /* give urb back to the driver */
-       dev = usb_get_dev (urb->dev);
-       ehci_urb_done (ehci, urb, regs);
+       /* give urb back to the driver; completion often (re)submits */
+       dev = urb->dev;
+       ehci_urb_done(ehci, urb, 0);
+       retval = true;
        urb = NULL;
-
-       /* defer stopping schedule; completion can submit */
-       ehci->periodic_sched--;
-       if (!ehci->periodic_sched)
-               (void) disable_periodic (ehci);
+       (void) disable_periodic(ehci);
        ehci_to_hcd(ehci)->self.bandwidth_isoc_reqs--;
 
-       if (list_empty (&stream->td_list)) {
+       if (list_is_singular(&stream->td_list)) {
                ehci_to_hcd(ehci)->self.bandwidth_allocated
                                -= stream->bandwidth;
                ehci_vdbg (ehci,
@@ -1783,9 +2113,14 @@ sitd_complete (
                        (stream->bEndpointAddress & USB_DIR_IN) ? "in" : "out");
        }
        iso_stream_put (ehci, stream);
-       usb_put_dev (dev);
+       /* OK to recycle this SITD now that its completion callback ran. */
+done:
+       sitd->urb = NULL;
+       sitd->stream = NULL;
+       list_move(&sitd->sitd_list, &stream->free_list);
+       iso_stream_put(ehci, stream);
 
-       return 1;
+       return retval;
 }
 
 
@@ -1827,12 +2162,19 @@ static int sitd_submit (struct ehci_hcd *ehci, struct urb *urb,
        /* schedule ... need to lock */
        spin_lock_irqsave (&ehci->lock, flags);
        if (unlikely(!test_bit(HCD_FLAG_HW_ACCESSIBLE,
-                              &ehci_to_hcd(ehci)->flags)))
+                              &ehci_to_hcd(ehci)->flags))) {
                status = -ESHUTDOWN;
-       else
-               status = iso_stream_schedule (ehci, urb, stream);
-       if (status == 0)
+               goto done_not_linked;
+       }
+       status = usb_hcd_link_urb_to_ep(ehci_to_hcd(ehci), urb);
+       if (unlikely(status))
+               goto done_not_linked;
+       status = iso_stream_schedule(ehci, urb, stream);
+       if (status == 0)
                sitd_link_urb (ehci, urb, ehci->periodic_size << 3, stream);
+       else
+               usb_hcd_unlink_urb_from_ep(ehci_to_hcd(ehci), urb);
+done_not_linked:
        spin_unlock_irqrestore (&ehci->lock, flags);
 
 done:
@@ -1841,33 +2183,26 @@ done:
        return status;
 }
 
-#else
+/*-------------------------------------------------------------------------*/
 
-static inline int
-sitd_submit (struct ehci_hcd *ehci, struct urb *urb, gfp_t mem_flags)
+static void free_cached_itd_list(struct ehci_hcd *ehci)
 {
-       ehci_dbg (ehci, "split iso support is disabled\n");
-       return -ENOSYS;
-}
+       struct ehci_itd *itd, *n;
 
-static inline unsigned
-sitd_complete (
-       struct ehci_hcd         *ehci,
-       struct ehci_sitd        *sitd,
-       struct pt_regs          *regs
-) {
-       ehci_err (ehci, "sitd_complete %p?\n", sitd);
-       return 0;
+       list_for_each_entry_safe(itd, n, &ehci->cached_itd_list, itd_list) {
+               struct ehci_iso_stream  *stream = itd->stream;
+               itd->stream = NULL;
+               list_move(&itd->itd_list, &stream->free_list);
+               iso_stream_put(ehci, stream);
+       }
 }
 
-#endif /* USB_EHCI_SPLIT_ISO */
-
 /*-------------------------------------------------------------------------*/
 
 static void
-scan_periodic (struct ehci_hcd *ehci, struct pt_regs *regs)
+scan_periodic (struct ehci_hcd *ehci)
 {
-       unsigned        frame, clock, now_uframe, mod;
+       unsigned        now_uframe, frame, clock, clock_frame, mod;
        unsigned        modified;
 
        mod = ehci->periodic_size << 3;
@@ -1878,33 +2213,33 @@ scan_periodic (struct ehci_hcd *ehci, struct pt_regs *regs)
         * Touches as few pages as possible:  cache-friendly.
         */
        now_uframe = ehci->next_uframe;
-       if (HC_IS_RUNNING (ehci_to_hcd(ehci)->state))
-               clock = readl (&ehci->regs->frame_index);
-       else
+       if (HC_IS_RUNNING(ehci_to_hcd(ehci)->state)) {
+               clock = ehci_readl(ehci, &ehci->regs->frame_index);
+               clock_frame = (clock >> 3) % ehci->periodic_size;
+       } else  {
                clock = now_uframe + mod - 1;
+               clock_frame = -1;
+       }
+       if (ehci->clock_frame != clock_frame) {
+               free_cached_itd_list(ehci);
+               ehci->clock_frame = clock_frame;
+       }
        clock %= mod;
+       clock_frame = clock >> 3;
 
        for (;;) {
                union ehci_shadow       q, *q_p;
-               __le32                  type, *hw_p;
-               unsigned                uframes;
+               __hc32                  type, *hw_p;
+               unsigned                incomplete = false;
 
-               /* don't scan past the live uframe */
                frame = now_uframe >> 3;
-               if (frame == (clock >> 3))
-                       uframes = now_uframe & 0x07;
-               else {
-                       /* safe to scan the whole frame at once */
-                       now_uframe |= 0x07;
-                       uframes = 8;
-               }
 
 restart:
                /* scan each element in frame's queue for completions */
                q_p = &ehci->pshadow [frame];
                hw_p = &ehci->periodic [frame];
                q.ptr = q_p->ptr;
-               type = Q_NEXT_TYPE (*hw_p);
+               type = Q_NEXT_TYPE(ehci, *hw_p);
                modified = 0;
 
                while (q.ptr != NULL) {
@@ -1913,14 +2248,15 @@ restart:
                        int                     live;
 
                        live = HC_IS_RUNNING (ehci_to_hcd(ehci)->state);
-                       switch (type) {
+                       switch (hc32_to_cpu(ehci, type)) {
                        case Q_TYPE_QH:
                                /* handle any completions */
                                temp.qh = qh_get (q.qh);
-                               type = Q_NEXT_TYPE (q.qh->hw_next);
+                               type = Q_NEXT_TYPE(ehci, q.qh->hw->hw_next);
                                q = q.qh->qh_next;
-                               modified = qh_completions (ehci, temp.qh, regs);
-                               if (unlikely (list_empty (&temp.qh->qtd_list)))
+                               modified = qh_completions (ehci, temp.qh);
+                               if (unlikely(list_empty(&temp.qh->qtd_list) ||
+                                               temp.qh->needs_rescan))
                                        intr_deschedule (ehci, temp.qh);
                                qh_put (temp.qh);
                                break;
@@ -1928,52 +2264,75 @@ restart:
                                /* for "save place" FSTNs, look at QH entries
                                 * in the previous frame for completions.
                                 */
-                               if (q.fstn->hw_prev != EHCI_LIST_END) {
+                               if (q.fstn->hw_prev != EHCI_LIST_END(ehci)) {
                                        dbg ("ignoring completions from FSTNs");
                                }
-                               type = Q_NEXT_TYPE (q.fstn->hw_next);
+                               type = Q_NEXT_TYPE(ehci, q.fstn->hw_next);
                                q = q.fstn->fstn_next;
                                break;
                        case Q_TYPE_ITD:
-                               /* skip itds for later in the frame */
-                               rmb ();
-                               for (uf = live ? uframes : 8; uf < 8; uf++) {
-                                       if (0 == (q.itd->hw_transaction [uf]
-                                                       & ITD_ACTIVE))
-                                               continue;
-                                       q_p = &q.itd->itd_next;
-                                       hw_p = &q.itd->hw_next;
-                                       type = Q_NEXT_TYPE (q.itd->hw_next);
-                                       q = *q_p;
-                                       break;
+                               /* If this ITD is still active, leave it for
+                                * later processing ... check the next entry.
+                                * No need to check for activity unless the
+                                * frame is current.
+                                */
+                               if (frame == clock_frame && live) {
+                                       rmb();
+                                       for (uf = 0; uf < 8; uf++) {
+                                               if (q.itd->hw_transaction[uf] &
+                                                           ITD_ACTIVE(ehci))
+                                                       break;
+                                       }
+                                       if (uf < 8) {
+                                               incomplete = true;
+                                               q_p = &q.itd->itd_next;
+                                               hw_p = &q.itd->hw_next;
+                                               type = Q_NEXT_TYPE(ehci,
+                                                       q.itd->hw_next);
+                                               q = *q_p;
+                                               break;
+                                       }
                                }
-                               if (uf != 8)
-                                       break;
 
-                               /* this one's ready ... HC won't cache the
+                               /* Take finished ITDs out of the schedule
+                                * and process them:  recycle, maybe report
+                                * URB completion.  HC won't cache the
                                 * pointer for much longer, if at all.
                                 */
                                *q_p = q.itd->itd_next;
                                *hw_p = q.itd->hw_next;
-                               type = Q_NEXT_TYPE (q.itd->hw_next);
+                               type = Q_NEXT_TYPE(ehci, q.itd->hw_next);
                                wmb();
-                               modified = itd_complete (ehci, q.itd, regs);
+                               modified = itd_complete (ehci, q.itd);
                                q = *q_p;
                                break;
                        case Q_TYPE_SITD:
-                               if ((q.sitd->hw_results & SITD_ACTIVE)
-                                               && live) {
+                               /* If this SITD is still active, leave it for
+                                * later processing ... check the next entry.
+                                * No need to check for activity unless the
+                                * frame is current.
+                                */
+                               if (frame == clock_frame && live &&
+                                               (q.sitd->hw_results &
+                                                       SITD_ACTIVE(ehci))) {
+                                       incomplete = true;
                                        q_p = &q.sitd->sitd_next;
                                        hw_p = &q.sitd->hw_next;
-                                       type = Q_NEXT_TYPE (q.sitd->hw_next);
+                                       type = Q_NEXT_TYPE(ehci,
+                                                       q.sitd->hw_next);
                                        q = *q_p;
                                        break;
                                }
+
+                               /* Take finished SITDs out of the schedule
+                                * and process them:  recycle, maybe report
+                                * URB completion.
+                                */
                                *q_p = q.sitd->sitd_next;
                                *hw_p = q.sitd->hw_next;
-                               type = Q_NEXT_TYPE (q.sitd->hw_next);
+                               type = Q_NEXT_TYPE(ehci, q.sitd->hw_next);
                                wmb();
-                               modified = sitd_complete (ehci, q.sitd, regs);
+                               modified = sitd_complete (ehci, q.sitd);
                                q = *q_p;
                                break;
                        default:
@@ -1984,11 +2343,23 @@ restart:
                        }
 
                        /* assume completion callbacks modify the queue */
-                       if (unlikely (modified))
-                               goto restart;
+                       if (unlikely (modified)) {
+                               if (likely(ehci->periodic_sched > 0))
+                                       goto restart;
+                               /* short-circuit this scan */
+                               now_uframe = clock;
+                               break;
+                       }
                }
 
-               /* stop when we catch up to the HC */
+               /* If we can tell we caught up to the hardware, stop now.
+                * We can't advance our scan without collecting the ISO
+                * transfers that are still pending in this frame.
+                */
+               if (incomplete && HC_IS_RUNNING(ehci_to_hcd(ehci)->state)) {
+                       ehci->next_uframe = now_uframe;
+                       break;
+               }
 
                // FIXME:  this assumes we won't get lapped when
                // latencies climb; that should be rare, but...
@@ -2001,18 +2372,24 @@ restart:
                if (now_uframe == clock) {
                        unsigned        now;
 
-                       if (!HC_IS_RUNNING (ehci_to_hcd(ehci)->state))
+                       if (!HC_IS_RUNNING (ehci_to_hcd(ehci)->state)
+                                       || ehci->periodic_sched == 0)
                                break;
                        ehci->next_uframe = now_uframe;
-                       now = readl (&ehci->regs->frame_index) % mod;
+                       now = ehci_readl(ehci, &ehci->regs->frame_index) % mod;
                        if (now_uframe == now)
                                break;
 
                        /* rescan the rest of this frame, then ... */
                        clock = now;
+                       clock_frame = clock >> 3;
+                       if (ehci->clock_frame != clock_frame) {
+                               free_cached_itd_list(ehci);
+                               ehci->clock_frame = clock_frame;
+                       }
                } else {
                        now_uframe++;
                        now_uframe %= mod;
                }
-       } 
+       }
 }