Mysterious forces changing backlight brightness

Some mysterious forces are changing my laptop's brightness and I can't seem to figure it out what it is.
For example, if my battery gets below 10% (also, why 10%?), it automatically changes brightness to something very low.
Similarly, if battery gets fully charged, it changes brightness. It also happens when I plug it into the AC or remove the adapter.
I've looked everywhere, tried changing settings (I really don't remember which ones anymore), but nothing seems to work.
Also, I've xfce4-power-manager installed, but closing it doesn't seem to effect this backlight changing.
Laptop-mode-tools is also set up, but backlight control is disabled.
My only idea is that it's changed by the driver, but how can I control it?
edit:
[soz@arch ~]$ lspci | grep VGA
00:02.0 VGA compatible controller: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller (rev 09)
Also, changing backlight to vendor doesn't fix this. Instead it messes up xfce4-power-manager's backlight control.
Forgot to mention, I'm running a simple Openbox installation.
Last edited by socials (2013-11-15 20:47:44)

Alright, an update.
The same thing happens even without running X at all. Even the brightness control keyboard hotkeys work without an X server running.
So it seems that they interact directly with hardware and it's not related to software at all. I think it's safe to say that the brightness change events happening on charger plug/unplug are related to this as well.
So if there's nothing in BIOS (I checked) I guess it's not fixable. I could set up an dirty hack using acpi handler scripts although it seems like an awful solution.
Or have you guys any other ideas?

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Last edited by eDio (2014-08-18 23:27:52)

heimer16 wrote:
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Mysterious forces changing backlight brightness

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