After installing, error when running

[isaacsa51]

Just as the title says, when I run the program just pop an error, I have already installed all the dependencies, restarted my machine and just to say, I install the program from AUR using yay so, don't know why the issue.

The error is: PANIC Failed to create V4L2 device with id 50

[botiapa]

Please run the command with the -v flag, and post the output.

[isaacsa51]

Output:

isaac@manjaro-sa:~
> sudo mon2cam -v
[sudo] password for isaac: 
DEBUG Starting Mon2Cam with the following options: Options {
  framerate: 60,
  device: 50,
  resolution: "",
  ffmpeg: [],
  border: false,
  sound: false,
  wayland: false,
  loggerOptions: { verbose: true },
  execOptions: { verbose: true, output: 3 }
}
DEBUG Checking if V4L2 device exists
DEBUG V4L2 device not found with id 50, creating it

Exec Context: c02b0541-f32d-478e-9120-5e2ef36f62c2
    Exec Options:  { verbose: true, output: 3 }
    Exec Command: sudo modprobe -r v4l2loopback
    Exec Command Splits:  [sudo,modprobe,-r,v4l2loopback]
    Exec Result:  { code: 1, success: false },
 output: "modprobe: FATAL: Module v4l2loopback not found."
Exec Context: c02b0541-f32d-478e-9120-5e2ef36f62c2

Exec Context: 464bd7ff-d869-49b6-973b-839ec6f58e75
    Exec Options:  { verbose: true, output: 3 }
    Exec Command: sudo modprobe v4l2loopback video_nr=50 'card_label=Mon2Cam'
    Exec Command Splits:  [sudo,modprobe,v4l2loopback,video_nr=50,'card_label=Mon2Cam']
    Exec Result:  { code: 1, success: false },
 output: "modprobe: FATAL: Module v4l2loopback not found in directory /lib/modules/5.8.16-2-MANJARO"
Exec Context: 464bd7ff-d869-49b6-973b-839ec6f58e75

DEBUG Exiting
DEBUG V4L2 device created with id 50
PANIC Failed to create V4L2 device with id 50

[botiapa]

The V4l2loopback device is not installed correctly on your system. It should have been installed when you used yay, but it wasn't as it seems. The log clearly states: modprobe: FATAL: Module v4l2loopback not found in directory /lib/modules/5.8.16-2-MANJARO

Install the v4l2loopback module, and then mon2cam should work correctly.

[isaacsa51]

The V4l2loopback device is not installed correctly on your system. It should have been installed when you used yay, but it wasn't as it seems. The log clearly states: modprobe: FATAL: Module v4l2loopback not found in directory /lib/modules/5.8.16-2-MANJARO

Install the v4l2loopback module, and then mon2cam should work correctly.

Welp, I have installed all the modules of v4l2loopback founded by yay and nothing has been fixed haha

[andrew103]

@isaacsa51 @botiapa I had the same issue and it got resolved after recompiling v4l2loopback from source and installing it again in the steps outlined here. I assume the issue occurs when the system is restarted, but I haven't tested it yet. If that is the case, then the fix is likely running either sudo depmod -a in the v4l2 directory or sudo modprobe v4l2loopback or doing both.

[ShayBox]

You have to install the kernel headers for your kernel to get dkms modules to work on archlinux

You also don't compile from source on archlinux, you use a pkgbuild always, otherwise the package manager doesn't track the files and keep them up to date.

[andrew103]

Ah my bad. I missed that he was using manjaro. I run ubuntu 18.04 so I need to build from source.

[ShayBox]

Did you get this working?

[isaacsa51]

Did you get this working?

Sadly not, I just have the program installed but nothing got working still

[GamerGuy95953]

Having the same problem too but on Manjaro Cinnamon.

[PalanixYT]

guys have you installed your kernel headers?

[Tursh]

I had the same error on Arch which is pretty much the same as Manjaro. I fixed it by installing from pacman the linux headers and v4l2loopback-dkms and then rebooted. For me, a reboot was the solution so let me know if it works for you.

[rlad78]

For those of you running into this on Arch, not knowing how to do this:

You have to install the kernel headers for your kernel to get dkms modules to work on archlinux

Find the linux kernel you're using: uname -r

Then, using yay (or pacman -S with the specific package name), install the package that matches your kernel version: yay linux-headers should give you something like:

8 core/linux59-headers 5.9.16-1 (9.7 MiB 48.3 MiB) 
    Header files and scripts for building modules for Linux59 kernel
7 core/linux54-headers 5.4.97-1 (9.4 MiB 46.9 MiB) 
    Header files and scripts for building modules for Linux54 kernel
6 core/linux511-headers 5.11.rc7.d0207.g92bf226-1 (9.6 MiB 48.7 MiB) 
    Header files and scripts for building modules for Linux511 kernel
5 core/linux510-headers 5.10.15-1 (9.5 MiB 47.7 MiB) 
    Header files and scripts for building modules for Linux510 kernel
4 core/linux49-headers 4.9.257-1 (7.4 MiB 37.0 MiB) 
    Header files and scripts for building modules for Linux49 kernel
3 core/linux44-headers 4.4.257-1 (6.7 MiB 33.8 MiB) 
    Header files and scripts for building modules for Linux44 kernel
2 core/linux419-headers 4.19.175-1 (8.8 MiB 44.3 MiB) 
    Header files and scripts for building modules for Linux419 kernel
1 core/linux414-headers 4.14.221-1 (8.1 MiB 41.0 MiB) 
    Header files and scripts for building modules for Linux414 kernel
==> Packages to install (eg: 1 2 3, 1-3 or ^4)

Since I'm using 5.10, I chose linux510-headers. Installed the package and mon2cam worked perfectly afterwards.

Thanks @ShayBox !

[isaacsa51]

Yep, the problem was the linux-headers, I'm not a superuser at all in linux but installed the headers and logging out finally worked, thanks @ShayBox @rlad78