Bug#968181: linux-image-5.7.0-2-arm64: DRM unavailable on Rapsberry Pi 4B

[Ryutaroh Matsumoto <ryutaroh@ict.e.titech.ac.jp>]

Hi all,

This is an update to
Bug#968181: linux-image-5.7.0-2-arm64: DRM unavailable on Rapsberry Pi 4B

I compiled Linux 5.10.9 by myself, and xinit starts fine without installing
the Debian package xserver-xorg-video-fbdev. When I originally reported this
#968181, the graphics on my raspi can only be used through xserver-xorg-video-fbdev.

X server works fine by using
/dev/dri/card0 on my raspi 4B 8GB model.
DRI/DRM on raspi started to partially work.

On the other hand, gdm3 and weston gives the following error in dmesg,
"kernel: [drm:vc4_bo_create [vc4]] *ERROR* Failed to allocate from CMA:"
and no graphics come. Rendering by wayland does not work at all with
vc4.ko in 5.10.9.

Best regards, Ryutaroh