The problem: there are 16 brightness levels on my laptop, but pressing hotkeys
Fn+End adjusts brightness 3 steps at a time (e.g. from 0 to 3, or from 15 to 12).
I find it important to notice that at the login screen hotkeys work fine. But after login that odd behavior appears.
Also, if I give focus to a menu (e.g. click on File menu in firefox), hotkeys work fine.
xdotool key XF86MonBrightnessDown works fine, adjusting brightness by 1 step (checked with
I also installed
indicator-brightness - it shows 16 leves (0-15).
I tried setting
acpi_backlight=vendor in grub (inspired by this topic: http://ubuntuforums.org/showthread.php?t=1909184 with similar problem). It worked in that hotkeys became working fine. But problems with OSD notification, xdotool and brightness indicator arised. So I think that it's not a right solution.
It seems that after login something interferes in the hotkeys processing scheme. Any ideas?
Edit (additional info)
I made an observation that hotkeys work at hardware level - I can adjust brightness immediately after turning on my laptop (e.g. at the BIOS screen).
$ killall gnome-settings-daemonhotkeys adjust brightness by one step, but no notifications appear. Shortly
gnome-settings-daemonrecovers, and triple step issue returns.
acpi_listengives the following output (both keys sequentially):
$ acpi_listen ibm/hotkey HKEY 00000080 00001010 video LCD0 00000086 00000000 ibm/hotkey HKEY 00000080 00001011 video LCD0 00000087 00000000
At this point I thought that (1) hotkeys work at hardware level; (2)
ibm/hotkeytakes care of hotkeys; (3)
videotakes care too. Thus, triple step issue appears.
I tried blacklisting video (I expected that this will lead to a double step behavior), but nothing changed.
As a workaround, I created my own hotkeys in CompizConfig Settings Manager - as described here, but with
xdotool key --clearmodifiers XF86MonBrightnessUp xdotool key --clearmodifiers XF86MonBrightnessDown
So now I can either use initial hotkeys or new ones for finer adjustments.
There was already discussion for the case with double step: Lenovo ThinkPads, brightness function keys make two steps instead of one, looking for workaround:
the hardware just does it and then also sends out a signal saying the button's been pressed. Possibly you could unset the shortcut in System -> Preferences -> Keyboard Shortcuts for this action?
But I am eager to know,
- Why do I get triple step issue?
- How can I unset processing this hotkeys?
I would be very grateful if someone explains it.