firewire: ohci: enable cycle timer fix on ALi and NEC controllers

Discussed in "read_cycle_timer backwards for sub-cycle 0000, 0001",
http://thread.gmane.org/gmane.linux.kernel.firewire.devel/13704

Known bad controllers:
  ALi M5271, listed by lspci as M5253 [10b9:5253]
  NEC OrangeLink [1033:00cd] (rev 03)
  NEC uPD72874 [1033:00f2] (rev 01)
  VIA VT6306 [1106:3044] (rev 46)
  VIA VT6308P, listed by lspci as rev c0

Reported-by: Pieter Palmers <pieterp@joow.be>
Reported-by: Håkan Johansson <f96hajo@chalmers.se>
Reported-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

diff --git a/drivers/firewire/ohci.c b/drivers/firewire/ohci.c
index d6ba897..bf5e112 100644 (file)
--- a/drivers/firewire/ohci.c
+++ b/drivers/firewire/ohci.c
@@ -1817,13 +1817,14 @@ static u64 ohci_get_bus_time(struct fw_card *card)
                c2 = reg_read(ohci, OHCI1394_IsochronousCycleTimer);
        } else {
                /*
-                * VIA controllers have two bugs when updating the iso cycle
-                * timer register:
-                * 1) When the lowest six bits are wrapping around to zero,
+                * Some controllers exhibit one or more of the following bugs
+                * when updating the iso cycle timer register:
+                *  - When the lowest six bits are wrapping around to zero,
                 *    a read that happens at the same time will return garbage
                 *    in the lowest ten bits.
-                * 2) When the cycleOffset field wraps around to zero, the
+                *  - When the cycleOffset field wraps around to zero, the
                 *    cycleCount field is not incremented for about 60 ns.
+                *  - Occasionally, the entire register reads zero.
                 *
                 * To catch these, we read the register three times and ensure
                 * that the difference between each two consecutive reads is
@@ -2542,7 +2543,9 @@ static int __devinit pci_probe(struct pci_dev *dev,
 #endif
        ohci->bus_reset_packet_quirk = dev->vendor == PCI_VENDOR_ID_TI;
 
-       ohci->iso_cycle_timer_quirk = dev->vendor == PCI_VENDOR_ID_VIA;
+       ohci->iso_cycle_timer_quirk = dev->vendor == PCI_VENDOR_ID_AL   ||
+                                     dev->vendor == PCI_VENDOR_ID_NEC  ||
+                                     dev->vendor == PCI_VENDOR_ID_VIA;
 
        ar_context_init(&ohci->ar_request_ctx, ohci,
                        OHCI1394_AsReqRcvContextControlSet);