Re: [PATCH] xhci: Fix HIK camera control timeout on Etron hosts

[Mathias Nyman <mathias.nyman@linux.intel.com>]

On 9/16/26 04:33, Kuangyi Chiang wrote:
> Hi,
> 
> Thanks for the review.
> 
> Michal Pecio <michal.pecio@gmail.com> 於 2026年9月14日週一 下午7:09寫道：
>>
>> On Mon, 14 Sep 2026 09:30:33 +0800, Kuangyi Chiang wrote:
>>> Control transfers to the HIK 1080P Camera (2bdf:0280) can time out when
>>> the device is connected through an Etron xHCI host:
>>>
>>> [   48.363671] uvcvideo: Found UVC 1.00 device HIK 1080P Camera (2bdf:0280)
>>> [   53.465662] uvcvideo: Failed to set UVC probe control : -110 (exp. 26).
>>> [   58.585653] uvcvideo: Failed to query (129) UVC probe control : -110 (exp. 26).
>>> [   58.592967] uvcvideo: Failed to initialize the device (-5).
>>>
>>> Testing shows that at least 125 us between control transfers is required
>>> to avoid the timeout. Limit the workaround to the affected Etron host and
>>> USB device combination to avoid changing control-transfer timing for other
>>> devices.
>>
>> Any idea why it happens or why the delay helps?
> 
> We don't know the root cause yet, but we did some more testing.
> 
> We tested delays of 50us, 125us, and 200us. The issue was still
> reproducible with 50us, while 125us and 200us passed our test.
> 
> Our pass criterion is 30 successful plug/unplug cycles on each port.
> So 125us is the minimum delay we tested that consistently works.
> 

Are there issues with the control transfers already during enumeration
of the device, when reading descriptors etc, or are these issues only
visible after uvc driver is controlling the device?


> We also tried USB_QUIRK_DELAY_CTRL_MSG, but its 200ms delay is too
> long and causes UVC initialization to fail.
> 

Does it help if you as a hack set udev->quirks |= USB_QUIRK_DELAY_CTRL_MSG
_after_ enumeration and uvc initialization?

>> How many other HCs did you test this camera with?
> 
> The camera works with the EHCI host we tested without any delay.
> We can also reproduce a similar issue with an ASMedia ASM1142 xHCI
> host (1b21:1242). This patch, however, is limited to the Etron/HIK
> combination.

I think we should avoid usb device specific quirks in the xhci driver,
especially now that we know it's not really tied to a specific xHC vendor.

If this is only an issue with the control transfers sent by uvc driver
then I think this device specific quirk should be in there.

Thanks
Mathias