Ubuntu - GPU - AMD GPU - Monitor - Manually - Check the DRM card number the GPU

DRM (Direct Rendering Manager) is a subsystem of the Linux kernel responsible for interfacing with GPUs of modern video cards.

ls /sys/class/drm/ -l

returns:

lrwxrwxrwx 1 root root    0 Jun  7 23:08 card0 -> ../../devices/pci0000:00/0000:00:03.1/0000:0a:00.0/0000:0b:00.0/0000:0c:00.0/drm/card0
lrwxrwxrwx 1 root root    0 Jun  7 23:08 card0-DP-1 -> ../../devices/pci0000:00/0000:00:03.1/0000:0a:00.0/0000:0b:00.0/0000:0c:00.0/drm/card0/card0-DP-1
lrwxrwxrwx 1 root root    0 Jun  7 23:08 card0-DP-2 -> ../../devices/pci0000:00/0000:00:03.1/0000:0a:00.0/0000:0b:00.0/0000:0c:00.0/drm/card0/card0-DP-2
lrwxrwxrwx 1 root root    0 Jun  7 23:08 card0-HDMI-A-1 -> ../../devices/pci0000:00/0000:00:03.1/0000:0a:00.0/0000:0b:00.0/0000:0c:00.0/drm/card0/card0-HDMI-A-1
lrwxrwxrwx 1 root root    0 Jun  7 23:08 card0-HDMI-A-2 -> ../../devices/pci0000:00/0000:00:03.1/0000:0a:00.0/0000:0b:00.0/0000:0c:00.0/drm/card0/card0-HDMI-A-2
lrwxrwxrwx 1 root root    0 Jun  7 23:08 renderD128 -> ../../devices/pci0000:00/0000:00:03.1/0000:0a:00.0/0000:0b:00.0/0000:0c:00.0/drm/renderD128
-r--r--r-- 1 root root 4.0K Jun  7 23:08 version

NOTE: This shows that there is only a single card, i.e. card0.

NOTE: Paths like /sys/class/drm/… are just symlinks and may change between reboots.

Persistent locations can be found in /sys/devices/.
- e.g. /sys/devices/pci0000:00/0000:00:01.0/0000:01:00.0/.

Adjust the commands accordingly for a reliable result.

References

https://dri.freedesktop.org/wiki/DRM/