I have a Raspberry Pi 4/Raspbian and am now attempting to open
/dev/dri/renderD128 for talking to V3D DRM. This fails with
Looking into the filesystem:
$ ls -l /dev/dri/renderD128 crw-rw---- 1 root render 226, 128 Aug 1 23:17 /dev/dri/renderD128 $ groups pi adm dialout cdrom sudo audio video plugdev games users input netdev gpio i2c spi
This seems correct, since
pi is not a user of
Reading up on this it seems that I should magically (this seems largely undocumented) get access to
renderD128 through a mechanism called UACCESS.
The rules contain:
SUBSYSTEM=="drm", KERNEL=="renderD*", TAG+="uaccess"
so I assume, this should be configured correctly!?
Could anyone explain how this should work or how I can further debug that UACCESS mechanism?