Intel 82Q35 Express Integrated Graphics Controller: blank screen on LVDS connector

Hardware:

Toshiba SurePOS 500

https://www.dennree-biowin.de/hardware/kassen/toshiba/toshiba-surepos-500

Symptom:

• display goes blank on boot on debian 11 bullseye (kernel 5.10).
• seems to happen on drm initialization.The kernel boot and systemd start are shown.
• machine is accessible via SSH
• display worked fine on debian 10 buster (kernel 4.19)
• display is internally connected via LVDS and not VGA
• running drm-tip kernel does not fix the issue

Debian bug:

https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1000481

Attaching the required information, running drm-tip kernel

vbios.dump

dmidecode.txt

dmesg.txt

dmesg with drm.debug=0x1e log_buf_len=4M

dmesg.txt

xrandr.txt

intel_gpu_abrt.tar

Xrandr output on a working debian 10 buster:

xrandr_working.txt