The kernel stuffs the keystrokes into the keyboard controller to change the brightness. I have not found this in the kernel source, but putting various numbers to /sys/devices/virtual/backlight/acpi_video0/brightness changes the brightness and makes the halevt -i report the keystrokes.
The gnome-power-manager receives these keystrokes and tries to change the brightness, and as the levels round incorrectly, we have an infinite loop.
There are two possible solutions then:
- make the gnome-power-manager not attempt to change the brightness on receiving the keystrokes
- use xrandr --output LVDS --set BACKLIGHT_CONTROL combination
I have put this line in /etc/X11/Xsession.d/99setbacklittocombination. It works for me. I do not use KMS, for KMS you should put LVDS1 instead of LVDS
I finally understand what is going on.
The kernel stuffs the keystrokes into the keyboard controller to change the brightness. I have not found this in the kernel source, but putting various numbers to /sys/devices/ virtual/ backlight/ acpi_video0/ brightness changes the brightness and makes the halevt -i report the keystrokes. Xsession. d/99setbacklitt ocombination. It works for me. I do not use KMS, for KMS you should put LVDS1 instead of LVDS
The gnome-power-manager receives these keystrokes and tries to change the brightness, and as the levels round incorrectly, we have an infinite loop.
There are two possible solutions then:
- make the gnome-power-manager not attempt to change the brightness on receiving the keystrokes
- use xrandr --output LVDS --set BACKLIGHT_CONTROL combination
I have put this line in /etc/X11/