Unable to open DRM node: No such file or directory

[bill790]

./v4l2-request-test -v /dev/video0 -m /dev/media0
Config:
Video path: /dev/video0
Media path: /dev/media0
DRM path: /dev/dri/card0
DRM driver: sun4i-drm
Slices path: data/bbb-mpeg2
Slices filename format: slice-%d.dump
FPS: 0

Preset:
Name: bbb-mpeg2
Description: big_buck_bunny_480p_MPEG2_MP2_25fps_1800K.MPG
License: Creative Commons Attribution 3.0
Attribution: Blender Foundation | www.blender.org
Width: 854
Height: 480
Frames count: 25
Format: MPEG2

Media device driver: sun6i-csi
Unable to open DRM node: No such file or directory

[luusl]

I have the same problem, but I thought it is a problem of the libva-v4l2-request project. See bootlin/libva-v4l2-request#27 (comment).

[paulkocialkowski]

Hi! First off, it looks like using /dev/video0 will not work for your case, as the node is backed by driver sun6i-csi instead of cedrus. You certainly have other /dev/video nodes and you need to adjust to the one matching cedrus. It is announced at boot, with a line like:

cedrus 1c0e000.video-codec: Device registered as /dev/video0

Then, the Unable to open DRM node: No such file or directory issue seems to indicate that there is no DRM driver running on your device (or that it failed to initialize). DRM support is a prerequisite for using this tool, as you can see. Most platforms supported by cedrus should also have DRM support, so you probably need to enable it in your kernel config and/or in the board's device-tree file.

Closing since this is not an issue of the tool but a setup issue instead,