Re: [PATCH v5 2/3] media: uvcvideo: add UVC_QUIRK_CTRL_THROTTLE for fragile firmware

Michal Pecio
2026-04-13T20:24:39Z

On Fri, 10 Apr 2026 16:06:43 -0700, Jeffrey Hein wrote:
> Test 2: Michal's xhci patch ONLY (clean isolation)
> ====================================================
> Active: ONLY Michal's xhci patch. No usbcore.quirks cmdline, stock
> uvcvideo (DKMS module disabled), LPM and autosuspend at defaults.
>
> Result: HC survived.
>
> Video call ran successfully.

Something weird when video was being disabled:

[Fri Apr 10 15:44:31 2026] xhci_hcd 0000:00:14.0: Spurious event dma 0x0000000272e42200, comp_code 13 after 13
[Fri Apr 10 15:44:31 2026] xhci_hcd 0000:00:14.0: Spurious event dma 0x0000000272e42230, comp_code 13 after 13
[Fri Apr 10 15:44:31 2026] xhci_hcd 0000:00:14.0: Cancel URB 0000000052d839d8, dev 3.1, ep 0x81, starting at offset 0x272e42f00
[Fri Apr 10 15:44:31 2026] xhci_hcd 0000:00:14.0: // Ding dong!
[Fri Apr 10 15:44:31 2026] xhci_hcd 0000:00:14.0: Stopped on Transfer TRB for slot 36 ep 2
[Fri Apr 10 15:44:31 2026] xhci_hcd 0000:00:14.0: Removing canceled TD starting at 0x272e42f00 (dma) in stream 0 URB 0000000052d839d8
[...]
[Fri Apr 10 15:44:31 2026] xhci_hcd 0000:00:14.0: xhci_giveback_invalidated_tds: Giveback cancelled URB 0000000052d839d8 TD
[Fri Apr 10 15:44:31 2026] xhci_hcd 0000:00:14.0: Cancel URB 00000000d8d84b58, dev 3.1, ep 0x81, starting at offset 0x260549210
[Fri Apr 10 15:44:31 2026] xhci_hcd 0000:00:14.0: // Ding dong!
[Fri Apr 10 15:44:31 2026] xhci_hcd 0000:00:14.0: ERROR Unknown event condition 198 for slot 36 ep 2 , HC probably busted
[Fri Apr 10 15:44:31 2026] xhci_hcd 0000:00:14.0: ERROR Unknown event condition 198 for slot 36 ep 2 , HC probably busted
[Fri Apr 10 15:44:31 2026] xhci_hcd 0000:00:14.0: ERROR Unknown event condition 198 for slot 36 ep 2 , HC probably busted
[Fri Apr 10 15:44:31 2026] xhci_hcd 0000:00:14.0: ERROR Unknown event condition 198 for slot 36 ep 2 , HC probably busted
[Fri Apr 10 15:44:31 2026] xhci_hcd 0000:00:14.0: ERROR Unknown event condition 198 for slot 36 ep 2 , HC probably busted
[Fri Apr 10 15:44:31 2026] xhci_hcd 0000:00:14.0: ERROR Unknown event condition 198 for slot 36 ep 2 , HC probably busted
[Fri Apr 10 15:44:31 2026] xhci_hcd 0000:00:14.0: ERROR Unknown event condition 198 for slot 36 ep 2 , HC probably busted
[Fri Apr 10 15:44:31 2026] xhci_hcd 0000:00:14.0: ERROR Unknown event condition 198 for slot 36 ep 2 , HC probably busted
[Fri Apr 10 15:44:31 2026] xhci_hcd 0000:00:14.0: Transfer error for slot 36 ep 2 on endpoint
[Fri Apr 10 15:44:31 2026] xhci_hcd 0000:00:14.0: ERROR Unknown event condition 198 for slot 36 ep 2 , HC probably busted
[Fri Apr 10 15:44:31 2026] xhci_hcd 0000:00:14.0: Stopped on Transfer TRB for slot 36 ep 2
[...]
[Fri Apr 10 15:44:31 2026] xhci_hcd 0000:00:14.0: drop ep 0x81, slot id 36, new drop flags = 0x8, new add flags = 0x0

Video started again, seemed to work for a while:

[Fri Apr 10 15:44:47 2026] xhci_hcd 0000:00:14.0: add ep 0x81, slot id 36, new drop flags = 0x0, new add flags = 0x8
[Fri Apr 10 15:44:47 2026] xhci_hcd 0000:00:14.0: xhci_check_bandwidth called for udev 00000000e40f0c43
[Fri Apr 10 15:44:47 2026] xhci_hcd 0000:00:14.0: // Ding dong!
[Fri Apr 10 15:44:47 2026] xhci_hcd 0000:00:14.0: Successful Endpoint Configure command
[Fri Apr 10 15:44:47 2026] usb 2-3.1: Hub-initiated U1 disabled due to long timeout 16800us
[Fri Apr 10 15:44:47 2026] usb 2-3.1: Hub-initiated U1 disabled due to long timeout 132us
[Fri Apr 10 15:44:47 2026] usb 2-3.1: Hub-initiated U1 disabled due to long timeout 1050us
[Fri Apr 10 15:44:47 2026] xhci_hcd 0000:00:14.0: Set up evaluate context for LPM MEL change.
[Fri Apr 10 15:44:47 2026] xhci_hcd 0000:00:14.0: // Ding dong!
[Fri Apr 10 15:44:47 2026] xhci_hcd 0000:00:14.0: Successful evaluate context command
[Fri Apr 10 15:44:47 2026] usb 2-3.1: Disable U2, ESIT shorter than exit latency
[Fri Apr 10 15:44:47 2026] xhci_hcd 0000:00:14.0: Spurious event dma 0x0000000260549020, comp_code 13 after 13
[Fri Apr 10 15:44:47 2026] xhci_hcd 0000:00:14.0: Spurious event dma 0x0000000260549050, comp_code 13 after 13

Until it broke, not sure what caused this. No EP5IN unlinks here.

[Fri Apr 10 15:45:09 2026] xhci_hcd 0000:00:14.0: Spurious event dma 0x0000000272e42690, comp_code 13 after 13
[Fri Apr 10 15:45:09 2026] xhci_hcd 0000:00:14.0: Spurious event dma 0x0000000272e426d0, comp_code 13 after 13
[Fri Apr 10 15:45:09 2026] xhci_hcd 0000:00:14.0: No Ping response error for slot 36 ep 2, Skip one Isoc TD
[Fri Apr 10 15:45:09 2026] xhci_hcd 0000:00:14.0: No Ping response error for slot 36 ep 2, Skip one Isoc TD
[Fri Apr 10 15:45:09 2026] xhci_hcd 0000:00:14.0: No Ping response error for slot 36 ep 2, Skip one Isoc TD

Then EP5IN also fails and is soft-retried, but it doesn't help.
Control requests get EPROTO or ETIMEDOUT as usual.

[Fri Apr 10 15:45:09 2026] xhci_hcd 0000:00:14.0: Transfer error for slot 36 ep 10 on endpoint
[Fri Apr 10 15:45:09 2026] xhci_hcd 0000:00:14.0: Soft-reset ep 10, slot 36

Looks like the device is dead indeed, or the HC broke down and
can't communiate with it.