releases/2.6.33.2/usb-ehci-fix-itd-list-order.patch

   1 From 92bc3648e6027384479852b770a542722fadee7c Mon Sep 17 00:00:00 2001
   2 From: Clemens Ladisch <clemens@ladisch.de>
   3 Date: Mon, 1 Mar 2010 09:12:50 +0100
   4 Subject: USB: EHCI: fix ITD list order
   5
   6 From: Clemens Ladisch <clemens@ladisch.de>
   7
   8 commit 92bc3648e6027384479852b770a542722fadee7c upstream.
   9
  10 When isochronous URBs are shorter than one frame and when more than one
  11 ITD in a frame has been completed before the interrupt can be handled,
  12 scan_periodic() completes the URBs in the order in which they are found
  13 in the descriptor list.  Therefore, the descriptor list must contain the
  14 ITDs in the correct order, i.e., a new ITD must be linked in after any
  15 previous ITDs of the same endpoint.
  16
  17 This should fix garbled capture data in the USB audio drivers.
  18
  19 Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
  20 Reported-by: Colin Fletcher <colin.m.fletcher@googlemail.com>
  21 Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
  22
  23 ---
  24  drivers/usb/host/ehci-sched.c |   24 +++++++++++++++++++-----
  25  1 file changed, 19 insertions(+), 5 deletions(-)
  26
  27 --- a/drivers/usb/host/ehci-sched.c
  28 +++ b/drivers/usb/host/ehci-sched.c
  29 @@ -1563,13 +1563,27 @@ itd_patch(
  30  static inline void
  31  itd_link (struct ehci_hcd *ehci, unsigned frame, struct ehci_itd *itd)
  32  {
  33 -       /* always prepend ITD/SITD ... only QH tree is order-sensitive */
  34 -       itd->itd_next = ehci->pshadow [frame];
  35 -       itd->hw_next = ehci->periodic [frame];
  36 -       ehci->pshadow [frame].itd = itd;
  37 +       union ehci_shadow       *prev = &ehci->pshadow[frame];
  38 +       __hc32                  *hw_p = &ehci->periodic[frame];
  39 +       union ehci_shadow       here = *prev;
  40 +       __hc32                  type = 0;
  41 +
  42 +       /* skip any iso nodes which might belong to previous microframes */
  43 +       while (here.ptr) {
  44 +               type = Q_NEXT_TYPE(ehci, *hw_p);
  45 +               if (type == cpu_to_hc32(ehci, Q_TYPE_QH))
  46 +                       break;
  47 +               prev = periodic_next_shadow(ehci, prev, type);
  48 +               hw_p = shadow_next_periodic(ehci, &here, type);
  49 +               here = *prev;
  50 +       }
  51 +
  52 +       itd->itd_next = here;
  53 +       itd->hw_next = *hw_p;
  54 +       prev->itd = itd;
  55         itd->frame = frame;
  56         wmb ();
  57 -       ehci->periodic[frame] = cpu_to_hc32(ehci, itd->itd_dma | Q_TYPE_ITD);
  58 +       *hw_p = cpu_to_hc32(ehci, itd->itd_dma | Q_TYPE_ITD);
  59  }
  60
  61  /* fit urb's itds into the selected schedule slot; activate as needed */