Webcam USB error

Support
1

I use a Midland W199 Webcam. When it is plugged in as USB device, I find in dmesg the following messages:

[    5.053018] usb 1-7: Warning! Unlikely big volume range (=5120), cval->res is probably wrong.
[    5.053023] usb 1-7: [5] FU [Mic Capture Volume] ch = 1, val = 7680/12800/1
[    5.053623] usbcore: registered new interface driver snd-usb-audio
[    5.059168] usb 1-7: Found UVC 1.00 device GENERAL WEBCAM (1b3f:2247)
[    5.059768] usb 1-7: UVC non compliance - GET_DEF(PROBE) not supported. Enabling workaround.
[    5.059960] usbcore: registered new interface driver uvcvideo
[   19.736857] usb 1-7: UVC non compliance: permanently disabling control 9a0901 (Auto Exposure), due to error -5

Is there a driver missing, or what can I do to avoid these error message?

2

Is there a problem?
These are totally normal log entries the system records every time the configuration changes/a device is added or removed.

3

But is it working? If so, don’t worry.

4

Lines 1+2 is a warning (not an error) about internal microphone volume range

Line 3 confirms audio driver snd-usb-audio is loaded,
so webcam should be listed as an audio capture device in ALSA - aplay -l
and PulseAudio or pipewire-pulse - pactl list cards short

Line 4 confirms webcam name and [Vendor ID:Product ID] code
ID codes can be used to check hardware scans from other Linux systems
https://linux-hardware.org/?id=usb:1b3f-2247

Lines 5+7 advise Auto Exposure control is not supported and is disabled

Line 6 confirms video driver uvcvideo is loaded
so webcam should be listed as a Graphics device - inxi -Ga

5

I did not do an exhaustive search, but it’s hard to find much information about this given model and Linux support (or people using it). And that looks far from a clean loading of that module.

I realise UVC standards changed everything, but still..

If the file below exists, you could try cranking up the logs.

echo 1 | sudo tee /sys/module/uvcvideo/parameters/trace
Edit: Sorry, just hopped on my system with a working UVC MS Modern Webcam. It appears ".../parameters/verbose" doesn't exist anymore in 6.17.

Do you know how many nights of no sleep it took, just to see my Logitech Quickcam to work at 240p@15Hz? Just to see yourself. Not do anything else! (Except dump to a file.) :laughing:

6

I run

echo 1 | sudo tee /sys/module/uvcvideo/parameters/trace

so that the value in trace file was changed from 0 to 1. Then I restarted the PC. The dmesg output stays as shown above. Can I find additional trace msg somewhere?

7

The /sys directory is a pseudo-filesystem — it is data exported from the kernel to userspace in the form of a browsable filesystem.

Whatever you write there will not survive a reboot. If you want it to be active again after a reboot, then you’ll have to tweak the pertinent configuration file for that service — if there is one — or create a script that will set the desired parameters again at boot time.

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8

It was only a hope that it would (temporarily) give more information in the logs. And you verified yourself, it unfortunately doesn’t do that.

9

Thank you all for replies - I understand the mentioned lines in dmesg are information but do not indicate an error.

10

Then let’s mark a more appropriate post as the solution, shall we?

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11

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