2013/6/25 Oon-Ee Ng

I have an ASUS N56V where the Fn-F{5,6} keys do not work natively (no output in xev when pressed). This is very easily worked-around using acpi_os="!Windows 2012".

The resulting control is something along the 3-10 range (10 being brightest and 0 being off, these are not the actual numerical values), which means I can't dim my backlight beyond a certain value. Similarly, using xbacklight and setting to 0 actually gives a "3" backlight, not totally blank. Setting /sys/class/backlight/intel_backlight/brightness to 0 does turn the screen off though.

The problem is that if I write a simple script to adjust brightness and bind that using xbindkeys, the native handler still works for a fraction of a second before the value I calculate takes effect. This results in a brief flicker everytime I press the keys.

Conclusion - I want to disable this native handling of Fn-F{5,6}, is this possible or is this not software-controlled?

I have a similar problem on a Dell XPS L701x - however, works natively but not work correctly, just setting the brightness from really bright to not-so-bright (but still very visible). xbacklight works, and on it all brightness levels are accessible. I also have a flickering effect when I use acpid for the keyboard key to call xbacklight. I think this probably has something to do with Nvidia Optimus, since both our systems have it (mine has a GT435M). I can also change it manually from /sys; but I'm not sure from where since I'm not with that system at the moment. I think it is from acpi_video0, however I have both it and intel_backlight in /sys/class/backlight/. One works, having a strange precision, going from 0 to ~6500 (not a round number), and the other doesn't. I noticed this also happens in Windows, but it is difficult to notice since it is handled really fast. -- Leonardo Dagnino