Comment 0 for bug 1749961

It was observed that while trying to use a 4K USB webcam connected to USB port
provided by ASMedia ASM1142 USB 3.1 Controller, the webcam does not work and kernel
log shows the following messages:

[431.928016] xhci_hcd 0000:12:00.0: ERROR Transfer event TRB DMA ptr not part of current TD ep_index 2 comp_code 13
[431.928021] xhci_hcd 0000:12:00.0: Looking for event-dma 0000003f3330e020 trb-start 0000003f3330e000 trb-end 0000003f3330e000 seg-start 0000003f3330e000 seg-end 0000003f3330eff0
[431.928024] xhci_hcd 0000:12:00.0: ERROR Transfer event TRB DMA ptr not part of current TD ep_index 2 comp_code 13
[431.928026] xhci_hcd 0000:12:00.0: Looking for event-dma 0000003f3330e030 trb-start 0000003f3330e000 trb-end 0000003f3330e000 seg-start 0000003f3330e000 seg-end 0000003f3330eff0
[431.928027] xhci_hcd 0000:12:00.0: ERROR Transfer event TRB DMA ptr not part of current TD ep_index 2 comp_code 13
[431.928029] xhci_hcd 0000:12:00.0: Looking for event-dma 0000003f3330e050 trb-start 0000003f3330e000 trb-end 0000003f3330e000 seg-start 0000003f3330e000 seg-end 0000003f3330eff0
[431.928386] xhci_hcd 0000:12:00.0: ERROR Transfer event TRB DMA ptr not part of current TD ep_index 2 comp_code 13

A similar issue was already reported on Launchpad: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1667750
The fix to this issue seems to be the following patch: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=9da5a109

Tests in our scenario with this patch proved still broken. Our next approach
is to modify the patch a bit and re-test.

This LP will be used to document our progress in the investigation.