17.18. DRM
DRM / DRI is the new interface that supersedes fbdev:
./build-buildroot --config 'BR2_PACKAGE_LIBDRM=y' ./build-userland --package libdrm -- userland/libs/libdrm/modeset.c ./run --eval-after './libs/libdrm/modeset.out' --graphic
Source: userland/libs/libdrm/modeset.c
Outcome: for a few seconds, the screen that contains the terminal gets taken over by changing colors of the rainbow.
TODO not working for aarch64, it takes over the screen for a few seconds and the kernel messages disappear, but the screen stays black all the time.
./build-buildroot --config 'BR2_PACKAGE_LIBDRM=y' ./build-userland --package libdrm ./build-buildroot ./run --eval-after './libs/libdrm/modeset.out' --graphic
kmscube however worked, which means that it must be a bug with this demo?
We set CONFIG_DRM=y on our default kernel configuration, and it creates one device file for each display:
# ls -l /dev/dri total 0 crw------- 1 root root 226, 0 May 28 09:41 card0 # grep 226 /proc/devices 226 drm # ls /sys/module/drm /sys/module/drm_kms_helper/
Try creating new displays:
./run --arch aarch64 --graphic -- -device virtio-gpu-pci
to see multiple /dev/dri/cardN, and then use a different display with:
./run --eval-after './libs/libdrm/modeset.out' --graphic
Bibliography:
Tested on: 93e383902ebcc03d8a7ac0d65961c0e62af9612b