There does appear to be a work around here:
https://wiki.archlinux.org/index.php/HP_Spectre_x360_13-4231ng#Brightness_/_backlight
It requires bc and inotify-tools.
The workaround is for a long running program to listen for changes to
/sys/class/backlight/intel_backlight
calculate the right luminance value
write them to xrandr.
Here's a slight improvement to the suggested script:
#!/bin/bash
#-----------------------------------------------------------------
# /usr/local/bin/brightness
# be sure this file is executable
#-----------------------------------------------------------------
backlight_path=/sys/class/backlight/intel_backlight
device=`xrandr | grep -w connected | awk '{ print $1 }'`
luminance() {
read -r level < "$backlight_path"/actual_brightness
bc <<< "scale=10;$level/$max"
}
read -r max < "$backlight_path"/max_brightness
xrandr --output "$device" --brightness "$(luminance)"
inotifywait -me modify --format '' "$backlight_path"/actual_brightness | while
read; do
echo "$device" $(luminance)
xrandr --output "$device" --brightness "$(luminance)"
done
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https://bugs.launchpad.net/bugs/1831587
Title:
brightness control not work with OLED panel
Status in HWE Next:
New
Status in OEM Priority Project:
New
Status in linux package in Ubuntu:
Triaged
Bug description:
image: disco 19.04
kernel: 5.0.0-15-generic
also verified failed on linux-image-unsigned-5.2.0-050200rc2-generic
also refer to :
-
https://askubuntu.com/questions/824949/lenovo-thinkpad-x1-yoga-oled-brightness
- https://bugs.freedesktop.org/show_bug.cgi?id=97883
Linux can not control the brightness on the OLED panel in the traditional way
[1].
Although there's a workaround from the community [2] that to execute script
while brightness hotkey event is triggered. But if we want to upstream it, it's
still a problem to recognize the OLED panel so that the system knows when to go
workaround.
- EDID of my laptop which has OLED: https://paste.ubuntu.com/p/w7rVqJTYDy/
- EDID of the same model without OLED: https://paste.ubuntu.com/p/P3ChhX9yBJ/
there's a kernel patch related OLED for reference:
- https://patchwork.kernel.org/patch/6133471/
[1] https://wiki.ubuntu.com/Kernel/Debugging/Backlight
[2]
https://askubuntu.com/questions/824949/lenovo-thinkpad-x1-yoga-oled-brightness
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