Arch Linux

MadCat_X

Member

Registered: 2009-10-08

Posts: 189

Integrated camera not working on T420 with Coreboot

In a fun attempt to get my T420 working again I upgraded a lot of the hardware and flashed Coreboot instead of the factory firmware. Everything has been working absolutely fine until today when I had to use the integrated camera for a videocall. The camera appears on the USB bus as

Bus 001 Device 003: ID 04f2:b221 Chicony Electronics Co., Ltd integrated camera

the uvcvideo module is loaded, /dev/video0 and /dev/video1 are available and detected by all programs that can use the camera. However, when I actually try to use the camera I do not get any picture and the activity led on the camera remains dark. There are no error messages in dmesg or journald that would give any hints as to what might be wrong. guvcview keeps reporting

V4L2_CORE: Could not grab image (select timeout): Resource temporarily unavailable

when it tries to access the camera but that is the only clue that something is wrong.

I have tried:
- Disabling pipewire to make sure that all applications can have direct access to /dev/video0
- Downgrading the kernel to LTS
- Booting very old Debian LiveCD with kernel 3.16
- Pulling the CMOS battery for over 30 minutes

Nothing helped.

I am absolutely certain that the camera used to work. Coreboot doesn't seem to have any toggle to disable the camera in the firmware. Any idea what might be going on?

gerdesj

Member

Registered: 2016-04-17

Posts: 13

Re: Integrated camera not working on T420 with Coreboot

To me a T420 is a Dell server!  So you have a Thinkpad T420.  According to https://forum.thinkpads.com/viewtopic.php?t=130182 it should just work. 

* Does the LED light ?
* Do you have permission to access /dev/videox ?