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    Subject[064/116] USB: EHCI: fix ITD list order
    2.6.32-stable review patch.  If anyone has any objections, please let us know.

    ------------------

    From: Clemens Ladisch <clemens@ladisch.de>

    commit 92bc3648e6027384479852b770a542722fadee7c upstream.

    When isochronous URBs are shorter than one frame and when more than one
    ITD in a frame has been completed before the interrupt can be handled,
    scan_periodic() completes the URBs in the order in which they are found
    in the descriptor list. Therefore, the descriptor list must contain the
    ITDs in the correct order, i.e., a new ITD must be linked in after any
    previous ITDs of the same endpoint.

    This should fix garbled capture data in the USB audio drivers.

    Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
    Reported-by: Colin Fletcher <colin.m.fletcher@googlemail.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

    ---
    drivers/usb/host/ehci-sched.c | 24 +++++++++++++++++++-----
    1 file changed, 19 insertions(+), 5 deletions(-)

    --- a/drivers/usb/host/ehci-sched.c
    +++ b/drivers/usb/host/ehci-sched.c
    @@ -1553,13 +1553,27 @@ itd_patch(
    static inline void
    itd_link (struct ehci_hcd *ehci, unsigned frame, struct ehci_itd *itd)
    {
    - /* always prepend ITD/SITD ... only QH tree is order-sensitive */
    - itd->itd_next = ehci->pshadow [frame];
    - itd->hw_next = ehci->periodic [frame];
    - ehci->pshadow [frame].itd = itd;
    + union ehci_shadow *prev = &ehci->pshadow[frame];
    + __hc32 *hw_p = &ehci->periodic[frame];
    + union ehci_shadow here = *prev;
    + __hc32 type = 0;
    +
    + /* skip any iso nodes which might belong to previous microframes */
    + while (here.ptr) {
    + type = Q_NEXT_TYPE(ehci, *hw_p);
    + if (type == cpu_to_hc32(ehci, Q_TYPE_QH))
    + break;
    + prev = periodic_next_shadow(ehci, prev, type);
    + hw_p = shadow_next_periodic(ehci, &here, type);
    + here = *prev;
    + }
    +
    + itd->itd_next = here;
    + itd->hw_next = *hw_p;
    + prev->itd = itd;
    itd->frame = frame;
    wmb ();
    - ehci->periodic[frame] = cpu_to_hc32(ehci, itd->itd_dma | Q_TYPE_ITD);
    + *hw_p = cpu_to_hc32(ehci, itd->itd_dma | Q_TYPE_ITD);
    }

    /* fit urb's itds into the selected schedule slot; activate as needed */



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