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. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
