Bug#990162: power consumption regression

[John <johnbast@protonmail.com>]

Tested Debian Bullseye RC2 - no Desktop Environment (GUI)

appended to /etc/sources on deb lines:
contrib nonfree

apt install firmware-misc-nonfree
apt install powertop

powertop --auto-tune run as a service at boot

/etc/default/grub contains
GRUB_CMDLINE_LINUX_DEFAULT="quiet consoleblank=5"
# update-grub

# cat /sys/module/kernel/parameters/consoleblank
5
(screen is blanked)

# cat /sys/devices/pci0000:00/0000:00:02.0/graphics/fb0/blank
(no value)

The dmesg errors are gone. The disk was repartitioned during install.

There is no longer a drop in power consumption at console blanking. We're back to +25%.

These do not have the desired power reduction effect:
echo 1 > /sys/devices/pci0000:00/0000:00:02.0/graphics/fb0/blank
(no change in power consumption)
echo > /sys/devices/pci0000:00/0000:00:02.0/graphics/fb0/blank
(disables blanking, screen blanks again after 5 seconds, same level of power consumption)

attempted again:
echo 1 > /sys/devices/pci0000:00/0000:00:02.0/graphics/fb0/blank
(no change in power consumption)

It seems no longer possible to use these settings as they were to reduce power consumption.
It seems power consumption reduction by the turning off console is not working.