In order to attempt to prevent the i915 error, this command was used: aptitude -t unstable install firmware-misc-nonfree
This installed firmware-misc-nonfree_20210315-2_all.deb. After rebooting, it seems to solve the i915 error. The power consumption (+25% compared to Debian 10.9) initially did not change because a single line message about the disk was still on screen, blocking blanking of the screen: dev/sda2: clean 5086/15177184 files, 1868566/60668160 blocks This remains on screen after running e2fsck /dev/sda2 booted from the installer usb. No errors reported. By using this workaround again: echo 1 > /sys/devices/pci0000:00/0000:00:02.0/graphics/fb0/blank and then echo > /sys/devices/pci0000:00/0000:00:02.0/graphics/fb0/blank The screen blanked. The login prompt was displayed shortly before blanking at the second command. Using the keyboard to wake now works and it is possible to login. After that, power consumption was reduced to +6% (down from +25%) above Debian 10 level. package: linux-image-5.10.0-8-amd64 version: 5.10.46-1 package: firmware-misc-nonfree version: 20210315-2 i915/kbl_dmc_ver1_04.bin is part of firmware-misc-nonfree 20210315-2 https://packages.debian.org/bullseye/firmware-linux-nonfree Also tested with similar result: package: firmware-misc-nonfree version: 20210322-1~exp1