Messages in this thread | | | Date | Sat, 18 Jan 2014 10:34:16 -0800 | From | walt <> | Subject | Re: [PATCH 3.12 033/118] usb: xhci: Link TRB must not occur within a USB payload burst [NEW HARDWARE] |
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On 01/17/2014 06:34 AM, David Laight wrote: > From: walt >> Oy, Sarah! ;) I put the ASMedia adapter in my older amd64 machine, and, well, >> the stupid thing Just Works(TM) with kernel 3.12.7! (Yes, with the same disk >> docking station, too.) >> >> I can't believe the adapter works perfectly in a different computer. Have you >> seen this kind of thing before? > > Could be a horrid timing race between the cpu and xchi controller. > If the cpu manages to write a NOP or LINK TRB for a following transfer > before the controller polls the next entry (after raising the IRQ) > then the controller might process the LINK and then get confused > when it can't process the linked-to TRB. > This might not sound likely, but PCIe has significant latency.
> Can you try the patch I posted that stops the ownership on LINK TRBs > being changed before that on the linked-to TRB?
David, the patch doesn't apply cleanly to any 3.12.x sources I can find, including the latest git from Linus. Half of the hunks fail. Could you create a fresh patch against vanilla 3.12.8 so I can test it? Or point me to the correct kernel sources, perhaps.
Thanks.
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