Webcam no longer working after move to Mint 19.3/20 <SOLVED>

[Prufrock]

I wonder if anyone can help with an issue after I moved to Mint 19.3? The external webcam I've been using with my desktop machine no longer works on Zoom, Cheese, Skype, etc. yet it worked fine on 18.3 and it still works fine when plugged into my laptop, also with 19.3. Even stranger, perhaps, is the fact that the webcam microphone does still work - at least a Zoom test shows it receiving a signal. Here's an extract from the the system information:

Mobo: Gigabyte model: 990XA-UD3 v: x.x serial: <filter> UEFI: American Megatrends v: FD date: 02/04/2013 ....
Device-4: Logitech QuickCam Pro 4000 type: USB driver: Philips webcam,snd-usb-audio bus ID: 5-1:2 chip ID: 046d:08b2

This is a fresh install of 19.3 and the hardware hasn't been changed since 18.3. I tried the upgrade path but there were too many glitches, broken packages, etc, so I started afresh with a 19.3 install but kept the old application files - and this is the only problem I've found so far. The system is up to date and both laptop and desktop are using the same version of Zoom, if that's relevant.

Be glad of some help, as this seems a trivial problem but not having a working camera on my desk at the moment is frustrating! Thanks

[erginemr]

Does it work on your desktop with Mint 19 Live DVD/USB?

Does it show up both in your laptop and desktop (installed version this time) with the following command:

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lsusb

[Prufrock]

Hi: thanks for the response. Using a Live USB version on the desktop with Cheese does work, which is odd but thanks for suggesting this. On the desktop installation, Cheese just says 'Camera not found' or 'There was an error playing video from the webcam'. One more odd thing: sometimes, when starting Zoom and testing the webcam the camera area is black but at other times this is all green. In all case Zoom identifies the webcam by name (Logitech QuickCam Pro 4000) and shows no other devices - and it seems to accept the audio input from the webcam microphone.

Here are the results from lsusb:
Desktop installation of 19.3:

Bus 005 Device 004: ID 046d:08b2 Logitech, Inc. QuickCam Pro 4000

Laptop (where the webcam works):

Bus 003 Device 004: ID 046d:08b2 Logitech, Inc. QuickCam Pro 4000

Live USB version on desktop machine:

Bus 005 Device 003: ID 046d:08b2 Logitech, Inc. QuickCam Pro 4000

So there doesn't seem to be a significant difference there.

Any suggestion for where to look further?

[erginemr]

A few more bullets and then I'm done.

Can you please get over the following thread, first:
viewtopic.php?f=248&t=322745

There is a useful command, which checks if the correct module (uvc universal driver here) is loaded:

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lsmod | grep "vl4\|uvc"

Please run this in your desktop (where your cam does not work) and post back.

Then, try another USB slot, if you haven't already.

Finally, check if both your laptop and desktop runs the same kernel:

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uname - a

[Prufrock]

Hi: thanks for picking this up. I think we're getting somewhere now!

Cheese works with the webcam on the laptop & on the USB live version on the desktop. On the desktop install, it does light up the camera LED and show a green rectangle, but no picture.

Kernel versions - the laptop is newer (5.3.0-61-generic #55~18.04.1-Ubuntu SMP), despite the desktop (5.4.0-39-generic #43~18.04.1-Ubuntu SMP) being more recent installed and supposedly fully up to date as well. However, since the webcam worked fine on Mint 18.3, I think the problem lies elsewhere - in the modules.

Here's the Laptop response to lsmod | grep "vl4\|uvc"

~$ lsmod | grep "vl4\|uvc"
uvcvideo 94208 0
v4l2_common 16384 1 uvcvideo
videobuf2_vmalloc 20480 1 uvcvideo
videobuf2_v4l2 24576 1 uvcvideo
videobuf2_common 49152 2 videobuf2_v4l2,uvcvideo
videodev 208896 4 v4l2_common,videobuf2_v4l2,uvcvideo,videobuf2_common
mc 53248 4 videodev,videobuf2_v4l2,uvcvideo,videobuf2_common

Desktop - nothing, just a blank!

~ $ lsmod | grep "vl4\|uvc"

If you have a little advice on how to install those mysteriously missing components, I'd be very grateful. Though I've been using Linus (mostly Mint) for some time, I'm really still a newbie on this sort of thing and a quick search didn't lead me very far.

[erginemr]

Let's add the module "uvcvideo" manually (in effect only for the current session) and see if it makes any difference:

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sudo modprobe uvcvideo

If it works this way, we shall make it permanent.

Besides, did you ascertain that USB slot is not the culprit by trying other slots?

Also to eliminate the possibility of kernel incompatibility, can you please upgrade the laptop kernel to v.5.4 via Update Manager and see if the external webcam works there with the latest kernel? You can manage kernels under its menu and revert to an older one in case something goes wrong. And as a rule of thumb, you should always keep one older kernel installed as fallback.

[Prufrock]

OK, so I was wrong about those kernel versions! Very polite of you not to emphasise the point but instead just show me how to proceed. Both machines now on same kernels, 5.4.0-39-generic; the laptop still works fine. Have performed sudo modprobe uvcvideo on the desktop, with this result now:

uvcvideo 94208 0
videobuf2_vmalloc 20480 2 pwc,uvcvideo
videobuf2_v4l2 24576 2 pwc,uvcvideo
videobuf2_common 53248 3 videobuf2_v4l2,pwc,uvcvideo
videodev 217088 4 videobuf2_v4l2,pwc,uvcvideo,videobuf2_common
mc 53248 5 videodev,snd_usb_audio,videobuf2_v4l2,uvcvideo,videobuf2_common

This seems to be missing a line from the laptop version, but perhaps this is because it's temporary?

However, Cheese still isn't playing - and has this new message:

(cheese:7619): cheese-WARNING **: 12:12:42.592: Failed to allocate required memory.: gstv4l2src.c(658): gst_v4l2src_decide_allocation (): /GstCameraBin:camerabin/GstWrapperCameraBinSrc:camera_source/GstBin:bin18/GstV4l2Src:v4l2src1:
Buffer pool activation failed

As for changing the USB port - well, I'm afraid I didn't because (a) it had worked with 18.3 (b) it's the only easily accessible one on the case. The other is in use for a mouse receiver and round the back is awkward for an item I move around. I have now switched the two case ports round - no difference.

Anyway, here's what happen if I plug straight into a motherboard USB2 port:

Webcam is identified on the new port with lsusb:

Bus 004 Device 005: ID 046d:08b2 Logitech, Inc. QuickCam Pro 4000

Still no result from Cheese:

(cheese:10511): cheese-WARNING **: 14:23:17.811: Device '/dev/video0' is busy: gstv4l2object.c(3754): gst_v4l2_object_set_format_full (): /GstCameraBin:camerabin/GstWrapperCameraBinSrc:camera_source/GstBin:bin18/GstV4l2Src:v4l2src1:
Call to S_FMT failed for YU12 @ 640x480: Device or resource busy

If I use the USB3 port on the desktop's internal card reader, cheese behaves a bit better - no message such the one about setup below. But Cheese still only shows a blank screen or the green screen effect. Zoom sees the camera name but shows a black rectange.

The handy USB3 ports on the monitor never seemed to play with this camera (or some USB2 drives, though happy with most): here's what Cheese says if I try one: 'no device found' on screen. (Zoom doesn't see the webcam at all.)

** Message: 12:50:05.303: cheese-application.vala:211: Error during camera setup: No device found
(cheese:8380): cheese-CRITICAL **: 12:50:05.315: cheese_camera_device_get_name: assertion 'CHEESE_IS_CAMERA_DEVICE (device)' failed
(cheese:8380): GLib-CRITICAL **: 12:50:05.315: g_variant_new_string: assertion 'string != NULL' failed
(cheese:8380): GLib-CRITICAL **: 12:50:05.315: g_variant_ref_sink: assertion 'value != NULL' failed
(cheese:8380): GLib-GIO-CRITICAL **: 12:50:05.315: g_settings_schema_key_type_check: assertion 'value != NULL' failed
(cheese:8380): GLib-CRITICAL **: 12:50:05.315: g_variant_get_type_string: assertion 'value != NULL' failed
(cheese:8380): GLib-GIO-CRITICAL **: 12:50:05.315: g_settings_set_value: key 'camera' in 'org.gnome.Cheese' expects type 's', but a GVariant of type '(null)' was given
(cheese:8380): GLib-CRITICAL **: 12:50:05.315: g_variant_unref: assertion 'value != NULL' failed
** (cheese:8380): CRITICAL **: 12:50:05.315: cheese_preferences_dialog_setup_resolutions_for_device: assertion 'device != NULL' failed

Hope you can advise, as you have so far! Thanks again - feels as though I'm almost there!

[erginemr]

Well, I am as dumfounded as you are, at my wits' end with this.

Let's see: On one hand, you have a webcam which worked before and which works now on Live DVD. On the other, the same webcam decides to play mischievous on the installed system, with same slots, same specs, same setup as the Live DVD.

I am thinking, something mıst be preventing the webcam to get the system resources to run (there were irq conflicts in old Windows version). And this could be related to usb slots, which brings us to...

Your mouse, does it share the usb receiver with the keyboard as a unified receiver? Do you have any other device using usb slots?

[erginemr]

This former / obsolete bug report:
https://bugs.launchpad.net/ubuntu/+sour ... ug/1445039

I ran into the same problem, and checked out the permissions on /dev/video0:

crw-rw----+ 1 root video 81, 0 Aug 22 11:14 /dev/video0

I also ran $(groups) to check my group membership and found that I wasn't in the group video. To rectify this, I ran $(sudo usermod -a -G video `whoami`), and after logging out and back in, I could use cheese normally again.

hints at a file permission problem or one of user/group privileges. An interesting take on, which deserves further checks.

[Prufrock]

Hi again. Thanks for the speedy replies - before I'd finished responding to the first one!

The mouse has sole use of the USB receiver (keyboard is wired USB). Other USB devices are several: scanner (but usually turned off), monitor USB hub (on a USB3 port), etc. In fact, here's a list after lsusb:

Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 007 Device 002: ID 0a5c:200a Broadcom Corp. BCM2035 Bluetooth dongle
Bus 007 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 006 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 002 Device 003: ID 058f:6362 Alcor Micro Corp. Flash Card Reader/Writer
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 005 Device 003: ID 0603:00f2 Novatek Microelectronics Corp. Keyboard (Labtec Ultra Flat Keyboard)
Bus 005 Device 008: ID 046d:08b2 Logitech, Inc. QuickCam Pro 4000
Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 004 Device 007: ID 046d:c52b Logitech, Inc. Unifying Receiver
Bus 004 Device 002: ID 0925:1234 Lakeview Research
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 011 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 010 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 009 Device 003: ID 0bda:0307 Realtek Semiconductor Corp.
Bus 009 Device 002: ID 05e3:0616 Genesys Logic, Inc. hub
Bus 009 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 008 Device 003: ID 05e3:0608 Genesys Logic, Inc. Hub
Bus 008 Device 002: ID 05e3:0610 Genesys Logic, Inc. 4-port hub
Bus 008 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

I guess I should install the missing UVC modules permanently? Seems really odd that they weren't there anyway. I have followed this up a bit and see that some QuickCam models have bugs that can be troublesome - though I'm not clear why it should only show now, when it worked before. And suppliers seem to have run out of new webcams at a decent price, at least here in the UK!

I'll take a look at the bug report and see if I can apply it to my system.

[Prufrock]

On that bug report, I've listed list the file video0 in /dev:

crw-rw----+ 1 root video 81, 0 Jun 26 16:44 video0

I'm not sure the groups are the problem: laptop & desktop show membership of same groups - neither has video:

[my username] adm cdrom sudo dip plugdev lpadmin sambashare

And the laptop, of course, doesn't have the problem.
Well, for now I'll just manage with the laptop when I need the webcam....

[erginemr]

I guess I should install the missing UVC modules permanently? Seems really odd that they weren't there anyway.

That part is easy, you just edit the file /etc/modules and append uvcvideo to the end. Open it with

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sudo nano /etc/modules

write uvcvideo to the end, save with Ctrl+O and exit with Ctrl+X. Then, restart the system and check lsusb for your logitech webcam.
While on it, please also install this webcam app guvcview to see what it does in its turn.

The above can also be done in a single command with a console mojo:

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echo "uvcvideo" | sudo tee -a /etc/modules

Nonetheless, I don't think it will work this way, the kernel normally loads the required module when it "sees" the device. Worth a try, anyway.

I'll take a look at the bug report and see if I can apply it to my system.

For that, let me give you my system feedback for a comparison:

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ls -l /dev/video0
crw-rw----+ 1 root video 81, 0 Jun 26 20:52 /dev/video0

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cat /etc/group | grep $USER
adm:x:4:syslog,ergin
cdrom:x:24:ergin
sudo:x:27:ergin
dip:x:30:ergin
plugdev:x:46:ergin
lpadmin:x:112:ergin
ergin:x:1000:
sambashare:x:128:ergin

I have an internal webcam on the laptop, which works. So, it seems I don't need to be part of the "video" group. If your settings are comparable, then you can let go of it.

[Prufrock]

Thanks for taking so much time on this - sorry it's turned out so troublesome. I began a reply last night but it was getting complicated and late, so have come back to this tonight. And now there's a slight difference - though no real improvement, alas.

As you suspected, installing the module made no difference. Running guvcview on start up failed to activate the camera properly, although guvcview could see it was there.

Message: guvcview error: you seem to have no video devices installed. Do you want to try one? (It then displays the Logitech QuickCam name)

Cheese fails, though with green screen, and so does Zoom.

There is however another clue if I compare the display of your system to mine just now. If I try ls -l /dev/video0 I get:

ls: cannot access '/dev/video0': No such file or directory

instead, in /dev/ I find there's this video line, but it's video1 not video0:

crw-rw----+ 1 root video 81, 1 Jun 27 21:25 /dev/video1

Which is odd. I shall try searching for any online explanation of that.

I also checked the groups I'm in, using cat /etc/group | grep $USER and they do match yours, so you're right, that doesn't seem to be the issue.

Sorry it's drawn a blank. As I said, I know I can use the laptop when I need to webcam, so that will have to do. It would have been very convenient to make the webcam work on the desktop, but you've spent a lot of time and I'm not sure it's worth longer. But I do appreciate your help, which hasn't been wasted - I've brushed up my terminal skills, learnt some new things and acquired another video camera tool, for use on the laptop at least!

So thanks!

[erginemr]

No problem for taking time.

As a final resort, you can try Mint 20, which has just been issued:
https://linuxmint.com/edition.php?id=281

You can boot the system with the Live DVD and check if the webcam works. This won't be conclusive however, given the fact that you had the same with Mint 19 Live DVD.

[Prufrock]

Thanks for the speedy reply! I might give Mint 20 a go - when I last looked it was still a Beta version, a bit too scary for me (as you see, I'd only just got round to moving to 19 on the desktop machine). But it's been released this very day, so thanks for the heads up. After all, it might work!

Thanks again.

[erginemr]

Keep your fingers crossed! Looking forward to good news from you...

[Prufrock]

Hi: One final update. Thanks for the propmpt to move to Mint 20. The good news is that it's working well and a couple of key programs that were causing problems in 19.3 are now running properly again - and in newer versions.

The not so good news: the webcam still doesn't work! Well, it does still work on 19.3 on the laptop, though if I run Mint 20 from a USB on that machine, it stops working there too. So I decided that was the end of the road for the camera - it's had a good run, owes me little now. I've ordered another that claims to work with Linux, so at least I can send it back if it won't. And I can use the laptop when needed as both the internal and plugged in camera still work there (which may explain why it coped better with the external camera, until Mint 20).

Thanks for your help. I can't really mark this as solved as it isn't, but it's been an interesting and useful journey and may help someone else save time on the same issue.

Thanks again!

[Prufrock]

I said the previous post was the final one - but there's one more. Finally, I can edit the heading to say it's solved, even if it meant new hardware.

The new webcam has arrived and it works in Mint 20! It works with Cheese and Guvcview. Not quite reliable in the USB3 hub on the monitor, better in the USB2 port on the computer case. Video for Zoom calls is a little bit more flaky, for some reason, but it does work most of the time too.

It's this model, if you're interested: Edis Full HD 1080p Webcam, bought in UK from CCL computers. Not cheap, but as it specifies it works in 'Linux with UVC driver' it meant I had some guarantee.