Re: xhci_hcd 0000:00:14.0: ERROR Transfer event TRB DMA ptr not part of current TD ep_index 1 comp_code 1

Paul Menzel
2024-04-08T16:37:58Z

Dear Mathias, dear Michał,

Thank you very much for your assistance.

Am 08.04.24 um 09:17 schrieb Mathias Nyman:
> On 7.4.2024 15.25, Michał Pecio wrote:
>> This (and the absence of any earlier errors on the endpoint) looks
>> like the hardware may be confirming a "successful" transfer twice or
>> the driver may be processing one such confirmation twice.
>
> It's also possible this TD/TRB was cancelled due to the disconnect.
> Could be that even if driver removes the TD from the list and cleans out
> the TRB from the ring buffer (turns TRB to no-op) hardware may have read
> ahead and cached the TRB, and process it anyway.
>
>> [   94.088594] usb 1-2: USB disconnect, device number 8
>> [   94.089370] xhci_hcd 0000:00:14.0: ERROR Transfer event TRB DMA ptr not part of current TD ep_index 1 comp_code 1
>> [   94.089403] xhci_hcd 0000:00:14.0: Looking for event-dma 00000001250310f0 trb-start 0000000125031100 trb-end 0000000125031100 seg-start 0000000125031000 seg-end 0000000125031ff0
>> [   94.089427] xhci_hcd 0000:00:14.0: last xhci_td_cleanup: first_dma 1250310f0 last_dma 1250310f0 status -115 from finish_td
>>
>> (I say "successful" but it really isn't - the device is no longer
>> listening. But there is no delivery confirmation on isochronous OUT
>> endpoints so the xHC doesn't suspect anything.)
>>
>> Could you try again with this updated debug patch to get more info?
>
> Would also be helpful to add xhci dynamic debug and xhci tracing (two
> separate logs). These will show in detail everything that is going on.
>
> Steps:
>
> mount -t debugfs none /sys/kernel/debug
> echo 'module xhci_hcd =p' >/sys/kernel/debug/dynamic_debug/control
> echo 'module usbcore =p' >/sys/kernel/debug/dynamic_debug/control
> echo 81920 > /sys/kernel/debug/tracing/buffer_size_kb
> echo 1 > /sys/kernel/debug/tracing/events/xhci-hcd/enable
> echo 1 > /sys/kernel/debug/tracing/tracing_on
> < Reproduce issue >
> Send output of dmesg
> Send content of /sys/kernel/debug/tracing/trace
>
> please copy the /sys/kernel/debug/tracing/trace file somewhere as soon
> as possible after reproducing the issue. It grows fast.

For posterity I created Linux Kernel Bugzilla issue #218695 [1], and
attached the files there. Hopefully everything was captured, that you
need. The discussion could continue on this list, but do as it suits you
best.

Kind regards,

Paul

[1]: https://bugzilla.kernel.org/show_bug.cgi?id=218695