Logitech HD Pro Webcam C920

[Russell L. Carter]

On 2020-03-25 08:59, Hans Petter Selasky wrote:
> On 2020-03-25 16:48, Russell L. Carter wrote:
>> On 2020-03-25 01:02, Hans Petter Selasky wrote:
>>> On 2020-03-24 21:10, Russell L. Carter wrote:

[...]

>>>
>>> The error message above means your webcam is not working properly. 
>>> Can you also show the output from usbconfig.
>>
>> root at feyerabend> usbconfig ugen5.11 dump_all_desc
>> ugen5.11: <vendor 0x046d HD Pro Webcam C920> at usbus5, cfg=255 
>> md=HOST spd=HIGH (480Mbps) pwr=ON (100mA)
>>
> 
> As long as it says cfg=255, the device won't work. It should say cfg=0.
> 
> Try to search for:
> 
>    idVendor = 0x046d
>    idProduct = 0x0892
> 
> On the internet. I think I recall that this specific device had some 
> known problems. You can also try another USB port and/or USB HUB.
> 
> Seem to be the same like:
> 
> https://forums.freebsd.org/threads/webcam-not-working.72746/
> 
> Looking at Linux, these devices are all quirked:
> 
> https://lore.kernel.org/patchwork/patch/864784/

These have truly excellent interfaces, thanks for the pointer.

> We don't have this quirk type yet in the kernel.
> 
> Try to play with these sysctls:
> 
> hw.usb.timings.extra_power_up_time: 20
> hw.usb.timings.resume_recovery: 50
> hw.usb.timings.resume_wait: 50
> hw.usb.timings.resume_delay: 250
> hw.usb.timings.set_address_settle: 10
> hw.usb.timings.port_resume_delay: 40
> hw.usb.timings.port_powerup_delay: 300
> hw.usb.timings.port_reset_recovery: 250
> hw.usb.timings.port_root_reset_delay: 200
> hw.usb.timings.port_reset_delay: 50
> 
> sysctl hw.usb.timings.set_address_settle=1000
> 
> Then re-plug the device.

I iterated through, setting each sysctl to 1000, plugging
in, and then setting it back to its default, and none
had any effect.  Maybe that saves time when the quirk
shows up in the future.

I'll have to zoom with windows for now, god I hate it.

Thanks,
Russell


> --HPS
>