u8 indicator[USB_MAXCHILDREN];
struct delayed_work leds;
struct delayed_work init_work;
+ void **port_owners;
};
return "480 Mb/s";
else if (portstatus & (1 << USB_PORT_FEAT_LOWSPEED))
return "1.5 Mb/s";
+ else if (portstatus & (1 << USB_PORT_FEAT_SUPERSPEED))
+ return "5.0 Gb/s";
else
return "12 Mb/s";
}
/* Note that hdev or one of its children must be locked! */
-static inline struct usb_hub *hdev_to_hub(struct usb_device *hdev)
+static struct usb_hub *hdev_to_hub(struct usb_device *hdev)
{
+ if (!hdev || !hdev->actconfig)
+ return NULL;
return usb_get_intfdata(hdev->actconfig->interface[0]);
}
unsigned long flags;
/* Suppress autosuspend until khubd runs */
- to_usb_interface(hub->intfdev)->pm_usage_cnt = 1;
+ atomic_set(&to_usb_interface(hub->intfdev)->pm_usage_cnt, 1);
spin_lock_irqsave(&hub_event_lock, flags);
if (!hub->disconnected && list_empty(&hub->event_list)) {
void usb_kick_khubd(struct usb_device *hdev)
{
- /* FIXME: What if hdev isn't bound to the hub driver? */
- kick_khubd(hdev_to_hub(hdev));
+ struct usb_hub *hub = hdev_to_hub(hdev);
+
+ if (hub)
+ kick_khubd(hub);
}
{
struct usb_hub *hub = urb->context;
int status = urb->status;
- int i;
+ unsigned i;
unsigned long bits;
switch (status) {
static inline int
hub_clear_tt_buffer (struct usb_device *hdev, u16 devinfo, u16 tt)
{
- return usb_control_msg(hdev, usb_rcvctrlpipe(hdev, 0),
+ return usb_control_msg(hdev, usb_sndctrlpipe(hdev, 0),
HUB_CLEAR_TT_BUFFER, USB_RT_PORT, devinfo,
tt, NULL, 0, 1000);
}
* talking to TTs must queue control transfers (not just bulk and iso), so
* both can talk to the same hub concurrently.
*/
-static void hub_tt_kevent (struct work_struct *work)
+static void hub_tt_work(struct work_struct *work)
{
struct usb_hub *hub =
- container_of(work, struct usb_hub, tt.kevent);
+ container_of(work, struct usb_hub, tt.clear_work);
unsigned long flags;
int limit = 100;
spin_lock_irqsave (&hub->tt.lock, flags);
while (--limit && !list_empty (&hub->tt.clear_list)) {
- struct list_head *temp;
+ struct list_head *next;
struct usb_tt_clear *clear;
struct usb_device *hdev = hub->hdev;
+ const struct hc_driver *drv;
int status;
- temp = hub->tt.clear_list.next;
- clear = list_entry (temp, struct usb_tt_clear, clear_list);
+ next = hub->tt.clear_list.next;
+ clear = list_entry (next, struct usb_tt_clear, clear_list);
list_del (&clear->clear_list);
/* drop lock so HCD can concurrently report other TT errors */
spin_unlock_irqrestore (&hub->tt.lock, flags);
status = hub_clear_tt_buffer (hdev, clear->devinfo, clear->tt);
- spin_lock_irqsave (&hub->tt.lock, flags);
-
if (status)
dev_err (&hdev->dev,
"clear tt %d (%04x) error %d\n",
clear->tt, clear->devinfo, status);
+
+ /* Tell the HCD, even if the operation failed */
+ drv = clear->hcd->driver;
+ if (drv->clear_tt_buffer_complete)
+ (drv->clear_tt_buffer_complete)(clear->hcd, clear->ep);
+
kfree(clear);
+ spin_lock_irqsave(&hub->tt.lock, flags);
}
spin_unlock_irqrestore (&hub->tt.lock, flags);
}
/**
- * usb_hub_tt_clear_buffer - clear control/bulk TT state in high speed hub
- * @udev: the device whose split transaction failed
- * @pipe: identifies the endpoint of the failed transaction
+ * usb_hub_clear_tt_buffer - clear control/bulk TT state in high speed hub
+ * @urb: an URB associated with the failed or incomplete split transaction
*
* High speed HCDs use this to tell the hub driver that some split control or
* bulk transaction failed in a way that requires clearing internal state of
* It may not be possible for that hub to handle additional full (or low)
* speed transactions until that state is fully cleared out.
*/
-void usb_hub_tt_clear_buffer (struct usb_device *udev, int pipe)
+int usb_hub_clear_tt_buffer(struct urb *urb)
{
+ struct usb_device *udev = urb->dev;
+ int pipe = urb->pipe;
struct usb_tt *tt = udev->tt;
unsigned long flags;
struct usb_tt_clear *clear;
if ((clear = kmalloc (sizeof *clear, GFP_ATOMIC)) == NULL) {
dev_err (&udev->dev, "can't save CLEAR_TT_BUFFER state\n");
/* FIXME recover somehow ... RESET_TT? */
- return;
+ return -ENOMEM;
}
/* info that CLEAR_TT_BUFFER needs */
: (USB_ENDPOINT_XFER_BULK << 11);
if (usb_pipein (pipe))
clear->devinfo |= 1 << 15;
-
+
+ /* info for completion callback */
+ clear->hcd = bus_to_hcd(udev->bus);
+ clear->ep = urb->ep;
+
/* tell keventd to clear state for this TT */
spin_lock_irqsave (&tt->lock, flags);
list_add_tail (&clear->clear_list, &tt->clear_list);
- schedule_work (&tt->kevent);
+ schedule_work(&tt->clear_work);
spin_unlock_irqrestore (&tt->lock, flags);
+ return 0;
}
-EXPORT_SYMBOL_GPL(usb_hub_tt_clear_buffer);
+EXPORT_SYMBOL_GPL(usb_hub_clear_tt_buffer);
/* If do_delay is false, return the number of milliseconds the caller
* needs to delay.
msecs_to_jiffies(delay));
/* Suppress autosuspend until init is done */
- to_usb_interface(hub->intfdev)->pm_usage_cnt = 1;
+ atomic_set(&to_usb_interface(hub->intfdev)->
+ pm_usage_cnt, 1);
return; /* Continues at init2: below */
} else {
hub_power_on(hub, true);
if (hub->has_indicators)
cancel_delayed_work_sync(&hub->leds);
if (hub->tt.hub)
- cancel_work_sync(&hub->tt.kevent);
+ cancel_work_sync(&hub->tt.clear_work);
}
/* caller has locked the hub device */
static int hub_configure(struct usb_hub *hub,
struct usb_endpoint_descriptor *endpoint)
{
+ struct usb_hcd *hcd;
struct usb_device *hdev = hub->hdev;
struct device *hub_dev = hub->intfdev;
u16 hubstatus, hubchange;
u16 wHubCharacteristics;
unsigned int pipe;
int maxp, ret;
- char *message;
+ char *message = "out of memory";
hub->buffer = usb_buffer_alloc(hdev, sizeof(*hub->buffer), GFP_KERNEL,
&hub->buffer_dma);
if (!hub->buffer) {
- message = "can't allocate hub irq buffer";
ret = -ENOMEM;
goto fail;
}
hub->status = kmalloc(sizeof(*hub->status), GFP_KERNEL);
if (!hub->status) {
- message = "can't kmalloc hub status buffer";
ret = -ENOMEM;
goto fail;
}
hub->descriptor = kmalloc(sizeof(*hub->descriptor), GFP_KERNEL);
if (!hub->descriptor) {
- message = "can't kmalloc hub descriptor";
ret = -ENOMEM;
goto fail;
}
dev_info (hub_dev, "%d port%s detected\n", hdev->maxchild,
(hdev->maxchild == 1) ? "" : "s");
+ hub->port_owners = kzalloc(hdev->maxchild * sizeof(void *), GFP_KERNEL);
+ if (!hub->port_owners) {
+ ret = -ENOMEM;
+ goto fail;
+ }
+
wHubCharacteristics = le16_to_cpu(hub->descriptor->wHubCharacteristics);
if (wHubCharacteristics & HUB_CHAR_COMPOUND) {
spin_lock_init (&hub->tt.lock);
INIT_LIST_HEAD (&hub->tt.clear_list);
- INIT_WORK (&hub->tt.kevent, hub_tt_kevent);
+ INIT_WORK(&hub->tt.clear_work, hub_tt_work);
switch (hdev->descriptor.bDeviceProtocol) {
case 0:
break;
ret);
hub->tt.hub = hdev;
break;
+ case 3:
+ /* USB 3.0 hubs don't have a TT */
+ break;
default:
dev_dbg(hub_dev, "Unrecognized hub protocol %d\n",
hdev->descriptor.bDeviceProtocol);
dev_dbg(hub_dev, "%umA bus power budget for each child\n",
hub->mA_per_port);
+ /* Update the HCD's internal representation of this hub before khubd
+ * starts getting port status changes for devices under the hub.
+ */
+ hcd = bus_to_hcd(hdev->bus);
+ if (hcd->driver->update_hub_device) {
+ ret = hcd->driver->update_hub_device(hcd, hdev,
+ &hub->tt, GFP_KERNEL);
+ if (ret < 0) {
+ message = "can't update HCD hub info";
+ goto fail;
+ }
+ }
+
ret = hub_hub_status(hub, &hubstatus, &hubchange);
if (ret < 0) {
message = "can't get hub status";
hub->urb = usb_alloc_urb(0, GFP_KERNEL);
if (!hub->urb) {
- message = "couldn't allocate interrupt urb";
ret = -ENOMEM;
goto fail;
}
hub_quiesce(hub, HUB_DISCONNECT);
usb_set_intfdata (intf, NULL);
+ hub->hdev->maxchild = 0;
if (hub->hdev->speed == USB_SPEED_HIGH)
highspeed_hubs--;
usb_free_urb(hub->urb);
+ kfree(hub->port_owners);
kfree(hub->descriptor);
kfree(hub->status);
usb_buffer_free(hub->hdev, sizeof(*hub->buffer), hub->buffer,
}
}
+/*
+ * Allow user programs to claim ports on a hub. When a device is attached
+ * to one of these "claimed" ports, the program will "own" the device.
+ */
+static int find_port_owner(struct usb_device *hdev, unsigned port1,
+ void ***ppowner)
+{
+ if (hdev->state == USB_STATE_NOTATTACHED)
+ return -ENODEV;
+ if (port1 == 0 || port1 > hdev->maxchild)
+ return -EINVAL;
+
+ /* This assumes that devices not managed by the hub driver
+ * will always have maxchild equal to 0.
+ */
+ *ppowner = &(hdev_to_hub(hdev)->port_owners[port1 - 1]);
+ return 0;
+}
+
+/* In the following three functions, the caller must hold hdev's lock */
+int usb_hub_claim_port(struct usb_device *hdev, unsigned port1, void *owner)
+{
+ int rc;
+ void **powner;
+
+ rc = find_port_owner(hdev, port1, &powner);
+ if (rc)
+ return rc;
+ if (*powner)
+ return -EBUSY;
+ *powner = owner;
+ return rc;
+}
+
+int usb_hub_release_port(struct usb_device *hdev, unsigned port1, void *owner)
+{
+ int rc;
+ void **powner;
+
+ rc = find_port_owner(hdev, port1, &powner);
+ if (rc)
+ return rc;
+ if (*powner != owner)
+ return -ENOENT;
+ *powner = NULL;
+ return rc;
+}
+
+void usb_hub_release_all_ports(struct usb_device *hdev, void *owner)
+{
+ int n;
+ void **powner;
+
+ n = find_port_owner(hdev, 1, &powner);
+ if (n == 0) {
+ for (; n < hdev->maxchild; (++n, ++powner)) {
+ if (*powner == owner)
+ *powner = NULL;
+ }
+ }
+}
+
+/* The caller must hold udev's lock */
+bool usb_device_is_owned(struct usb_device *udev)
+{
+ struct usb_hub *hub;
+
+ if (udev->state == USB_STATE_NOTATTACHED || !udev->parent)
+ return false;
+ hub = hdev_to_hub(udev->parent);
+ return !!hub->port_owners[udev->portnum - 1];
+}
+
static void recursively_mark_NOTATTACHED(struct usb_device *udev)
{
recursively_mark_NOTATTACHED(udev);
spin_unlock_irqrestore(&device_state_lock, flags);
}
+EXPORT_SYMBOL_GPL(usb_set_device_state);
/*
* WUSB devices are simple: they have no hubs behind, so the mapping
* 0 is reserved by USB for default address; (b) Linux's USB stack
* uses always #1 for the root hub of the controller. So USB stack's
* port #1, which is wusb virtual-port #0 has address #2.
+ *
+ * Devices connected under xHCI are not as simple. The host controller
+ * supports virtualization, so the hardware assigns device addresses and
+ * the HCD must setup data structures before issuing a set address
+ * command to the hardware.
*/
static void choose_address(struct usb_device *udev)
{
* (Includes HNP test device.)
*/
if (udev->bus->b_hnp_enable || udev->bus->is_b_host) {
- err = usb_port_suspend(udev);
+ err = usb_port_suspend(udev, PMSG_SUSPEND);
if (err < 0)
dev_dbg(&udev->dev, "HNP fail, %d\n", err);
}
err = usb_configure_device(udev); /* detect & probe dev/intfs */
if (err < 0)
goto fail;
+ dev_dbg(&udev->dev, "udev %d, busnum %d, minor = %d\n",
+ udev->devnum, udev->bus->busnum,
+ (((udev->bus->busnum-1) * 128) + (udev->devnum-1)));
/* export the usbdev device-node for libusb */
udev->dev.devt = MKDEV(USB_DEVICE_MAJOR,
(((udev->bus->busnum-1) * 128) + (udev->devnum-1)));
void usb_ep0_reinit(struct usb_device *udev)
{
- usb_disable_endpoint(udev, 0 + USB_DIR_IN);
- usb_disable_endpoint(udev, 0 + USB_DIR_OUT);
+ usb_disable_endpoint(udev, 0 + USB_DIR_IN, true);
+ usb_disable_endpoint(udev, 0 + USB_DIR_OUT, true);
usb_enable_endpoint(udev, &udev->ep0, true);
}
EXPORT_SYMBOL_GPL(usb_ep0_reinit);
static int hub_set_address(struct usb_device *udev, int devnum)
{
int retval;
+ struct usb_hcd *hcd = bus_to_hcd(udev->bus);
- if (devnum <= 1)
+ /*
+ * The host controller will choose the device address,
+ * instead of the core having chosen it earlier
+ */
+ if (!hcd->driver->address_device && devnum <= 1)
return -EINVAL;
if (udev->state == USB_STATE_ADDRESS)
return 0;
if (udev->state != USB_STATE_DEFAULT)
return -EINVAL;
- retval = usb_control_msg(udev, usb_sndaddr0pipe(),
- USB_REQ_SET_ADDRESS, 0, devnum, 0,
- NULL, 0, USB_CTRL_SET_TIMEOUT);
+ if (hcd->driver->address_device) {
+ retval = hcd->driver->address_device(hcd, udev);
+ } else {
+ retval = usb_control_msg(udev, usb_sndaddr0pipe(),
+ USB_REQ_SET_ADDRESS, 0, devnum, 0,
+ NULL, 0, USB_CTRL_SET_TIMEOUT);
+ if (retval == 0)
+ update_address(udev, devnum);
+ }
if (retval == 0) {
/* Device now using proper address. */
- update_address(udev, devnum);
usb_set_device_state(udev, USB_STATE_ADDRESS);
usb_ep0_reinit(udev);
}
static DEFINE_MUTEX(usb_address0_mutex);
struct usb_device *hdev = hub->hdev;
+ struct usb_hcd *hcd = bus_to_hcd(hdev->bus);
int i, j, retval;
unsigned delay = HUB_SHORT_RESET_TIME;
enum usb_device_speed oldspeed = udev->speed;
mutex_lock(&usb_address0_mutex);
- /* Reset the device; full speed may morph to high speed */
- retval = hub_port_reset(hub, port1, udev, delay);
- if (retval < 0) /* error or disconnect */
+ if ((hcd->driver->flags & HCD_USB3) && udev->config) {
+ /* FIXME this will need special handling by the xHCI driver. */
+ dev_dbg(&udev->dev,
+ "xHCI reset of configured device "
+ "not supported yet.\n");
+ retval = -EINVAL;
goto fail;
- /* success, speed is known */
+ } else if (!udev->config && oldspeed == USB_SPEED_SUPER) {
+ /* Don't reset USB 3.0 devices during an initial setup */
+ usb_set_device_state(udev, USB_STATE_DEFAULT);
+ } else {
+ /* Reset the device; full speed may morph to high speed */
+ /* FIXME a USB 2.0 device may morph into SuperSpeed on reset. */
+ retval = hub_port_reset(hub, port1, udev, delay);
+ if (retval < 0) /* error or disconnect */
+ goto fail;
+ /* success, speed is known */
+ }
retval = -ENODEV;
if (oldspeed != USB_SPEED_UNKNOWN && oldspeed != udev->speed) {
* reported as 0xff in the device descriptor). WUSB1.0[4.8.1].
*/
switch (udev->speed) {
+ case USB_SPEED_SUPER:
case USB_SPEED_VARIABLE: /* fixed at 512 */
- udev->ep0.desc.wMaxPacketSize = __constant_cpu_to_le16(512);
+ udev->ep0.desc.wMaxPacketSize = cpu_to_le16(512);
break;
case USB_SPEED_HIGH: /* fixed at 64 */
- udev->ep0.desc.wMaxPacketSize = __constant_cpu_to_le16(64);
+ udev->ep0.desc.wMaxPacketSize = cpu_to_le16(64);
break;
case USB_SPEED_FULL: /* 8, 16, 32, or 64 */
/* to determine the ep0 maxpacket size, try to read
* the device descriptor to get bMaxPacketSize0 and
* then correct our initial guess.
*/
- udev->ep0.desc.wMaxPacketSize = __constant_cpu_to_le16(64);
+ udev->ep0.desc.wMaxPacketSize = cpu_to_le16(64);
break;
case USB_SPEED_LOW: /* fixed at 8 */
- udev->ep0.desc.wMaxPacketSize = __constant_cpu_to_le16(8);
+ udev->ep0.desc.wMaxPacketSize = cpu_to_le16(8);
break;
default:
goto fail;
case USB_SPEED_LOW: speed = "low"; break;
case USB_SPEED_FULL: speed = "full"; break;
case USB_SPEED_HIGH: speed = "high"; break;
+ case USB_SPEED_SUPER:
+ speed = "super";
+ break;
case USB_SPEED_VARIABLE:
speed = "variable";
type = "Wireless ";
break;
default: speed = "?"; break;
}
- dev_info (&udev->dev,
- "%s %s speed %sUSB device using %s and address %d\n",
- (udev->config) ? "reset" : "new", speed, type,
- udev->bus->controller->driver->name, devnum);
+ if (udev->speed != USB_SPEED_SUPER)
+ dev_info(&udev->dev,
+ "%s %s speed %sUSB device using %s and address %d\n",
+ (udev->config) ? "reset" : "new", speed, type,
+ udev->bus->controller->driver->name, devnum);
/* Set up TT records, if needed */
if (hdev->tt) {
* value.
*/
for (i = 0; i < GET_DESCRIPTOR_TRIES; (++i, msleep(100))) {
- if (USE_NEW_SCHEME(retry_counter)) {
+ /*
+ * An xHCI controller cannot send any packets to a device until
+ * a set address command successfully completes.
+ */
+ if (USE_NEW_SCHEME(retry_counter) && !(hcd->driver->flags & HCD_USB3)) {
struct usb_device_descriptor *buf;
int r = 0;
* unauthorized address in the Connect Ack sequence;
* authorization will assign the final address.
*/
- if (udev->wusb == 0) {
+ if (udev->wusb == 0) {
for (j = 0; j < SET_ADDRESS_TRIES; ++j) {
retval = hub_set_address(udev, devnum);
if (retval >= 0)
devnum, retval);
goto fail;
}
+ if (udev->speed == USB_SPEED_SUPER) {
+ devnum = udev->devnum;
+ dev_info(&udev->dev,
+ "%s SuperSpeed USB device using %s and address %d\n",
+ (udev->config) ? "reset" : "new",
+ udev->bus->controller->driver->name, devnum);
+ }
/* cope with hardware quirkiness:
* - let SET_ADDRESS settle, some device hardware wants it
* - read ep0 maxpacket even for high and low speed,
*/
msleep(10);
- if (USE_NEW_SCHEME(retry_counter))
+ if (USE_NEW_SCHEME(retry_counter) && !(hcd->driver->flags & HCD_USB3))
break;
}
if (retval)
goto fail;
- i = udev->descriptor.bMaxPacketSize0 == 0xff? /* wusb device? */
- 512 : udev->descriptor.bMaxPacketSize0;
+ if (udev->descriptor.bMaxPacketSize0 == 0xff ||
+ udev->speed == USB_SPEED_SUPER)
+ i = 512;
+ else
+ i = udev->descriptor.bMaxPacketSize0;
if (le16_to_cpu(udev->ep0.desc.wMaxPacketSize) != i) {
if (udev->speed != USB_SPEED_FULL ||
!(i == 8 || i == 16 || i == 32 || i == 64)) {
/* For a suspended device, treat this as a
* remote wakeup event.
*/
- if (udev->do_remote_wakeup)
- status = remote_wakeup(udev);
-
- /* Otherwise leave it be; devices can't tell the
- * difference between suspended and disabled.
- */
- else
- status = 0;
+ status = remote_wakeup(udev);
#endif
} else {
}
usb_set_device_state(udev, USB_STATE_POWERED);
- udev->speed = USB_SPEED_UNKNOWN;
udev->bus_mA = hub->mA_per_port;
udev->level = hdev->level + 1;
udev->wusb = hub_is_wusb(hub);
- /* set the address */
- choose_address(udev);
- if (udev->devnum <= 0) {
- status = -ENOTCONN; /* Don't retry */
- goto loop;
+ /*
+ * USB 3.0 devices are reset automatically before the connect
+ * port status change appears, and the root hub port status
+ * shows the correct speed. We also get port change
+ * notifications for USB 3.0 devices from the USB 3.0 portion of
+ * an external USB 3.0 hub, but this isn't handled correctly yet
+ * FIXME.
+ */
+
+ if (!(hcd->driver->flags & HCD_USB3))
+ udev->speed = USB_SPEED_UNKNOWN;
+ else if ((hdev->parent == NULL) &&
+ (portstatus & (1 << USB_PORT_FEAT_SUPERSPEED)))
+ udev->speed = USB_SPEED_SUPER;
+ else
+ udev->speed = USB_SPEED_UNKNOWN;
+
+ /*
+ * xHCI needs to issue an address device command later
+ * in the hub_port_init sequence for SS/HS/FS/LS devices.
+ */
+ if (!(hcd->driver->flags & HCD_USB3)) {
+ /* set the address */
+ choose_address(udev);
+ if (udev->devnum <= 0) {
+ status = -ENOTCONN; /* Don't retry */
+ goto loop;
+ }
}
- /* reset and get descriptor */
+ /* reset (non-USB 3.0 devices) and get descriptor */
status = hub_port_init(hub, udev, port1, i);
if (status < 0)
goto loop;
udev->descriptor = descriptor; /* for disconnect() calls */
goto re_enumerate;
}
-
+
+ /* Restore the device's previous configuration */
if (!udev->actconfig)
goto done;
-
ret = usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
USB_REQ_SET_CONFIGURATION, 0,
udev->actconfig->desc.bConfigurationValue, 0,
}
usb_set_device_state(udev, USB_STATE_CONFIGURED);
+ /* Put interfaces back into the same altsettings as before.
+ * Don't bother to send the Set-Interface request for interfaces
+ * that were already in altsetting 0; besides being unnecessary,
+ * many devices can't handle it. Instead just reset the host-side
+ * endpoint state.
+ */
for (i = 0; i < udev->actconfig->desc.bNumInterfaces; i++) {
struct usb_interface *intf = udev->actconfig->interface[i];
struct usb_interface_descriptor *desc;
- /* set_interface resets host side toggle even
- * for altsetting zero. the interface may have no driver.
- */
desc = &intf->cur_altsetting->desc;
- ret = usb_set_interface(udev, desc->bInterfaceNumber,
- desc->bAlternateSetting);
+ if (desc->bAlternateSetting == 0) {
+ usb_disable_interface(udev, intf, true);
+ usb_enable_interface(udev, intf, true);
+ ret = 0;
+ } else {
+ ret = usb_set_interface(udev, desc->bInterfaceNumber,
+ desc->bAlternateSetting);
+ }
if (ret < 0) {
dev_err(&udev->dev, "failed to restore interface %d "
"altsetting %d (error=%d)\n",
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff