Re: Debian Bullseye on Raspberry Pi 4 4GB?

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

From: deloptes <deloptes@gmail.com>
> is the aarch64 bullseye kernel working on the RPI?
> The buster does not work, so I copied the raspberrypi kernel and it works
> fine.

Since I couldn't find an answer on the list, I write what I know.
I use RPi4B 8GB. Plain upstream kernel became fully functioning from
kernel version 5.8. Kernel version 5.9 was fine. 4K display output is
also possible by hdmi_enable_4kp60=1 "config.txt".
Gnome desktop environment works fine with 4K display.
We can install Linux kernel 5.10 from buster-backports, which is
the way to create images on raspi.debian.net for buster.

Linux kernel 5.10 have several regressions:
1. Unless reset_raspberrypi.ko is loaded by initramfs, USB boot becomes impossible.
2. 5GHz WiFi is blocked by the newly introduced vc4.ko.
3. According to Diederik on the linux-rpi-kernel list, the audio functionality is also
   affected by vc4.ko.
4. My btrfs root filesystem becomes completely unmountable once every week...

2 and 3 can be worked around by module_blacklist=vc4 in the kernel comand line.
Because of 4, I am using self-compiled upstreadm kernel 5.9.16...
Another intel laptop also becomes very unstable with kernel 5.10,
and I am staying away from 5.10.

Best regards, Ryutaroh Matsumoto