Sarah Sharp <sarah.a.sharp@...> writes:
>
> The Microsoft LifeChat 3000 USB headset was causing a very reproducible
> hang whenever it was plugged in. At first, I thought the host
> controller was producing bad transfer events, because the log was filled
> with errors like:
>
> xhci_hcd 0000:00:14.0: ERROR Transfer event TRB DMA ptr not part of current TD
>
> However, it turned out to be an xHCI driver bug in the ring expansion
> patches. The bug is triggered When there are two ring segments, and a
> TD that ends just before a link TRB, like so:
[snip]
> The transfer event would get ignored, the transfer would eventually
> timeout, and we would mistakenly convert the finished transfer to no-op
> TRBs. Some kernel driver (maybe xHCI?) would then get stuck in an
> infinite loop in interrupt context, and the whole machine would hang.
>
> This patch should be backported to kernels as old as 3.4, that contain
> the commit b008df60c6369ba0290fa7daa177375407a12e07 "xHCI: count free
> TRBs on transfer ring"
>
> Signed-off-by: Sarah Sharp <sarah.a.sharp@...>
> Cc: Andiry Xu <andiry.xu@...>
Running into this semi-consistently with a pl2303 usb serial adapter on v3.4
after upgrading from v3.3 to get the mentioned fix ("no room on ep ring").
Building a 3.4 with this patch at the moment, will report back with the outcome.
--Carey Underwood
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