Arch Linux

Seefo

Member

Registered: 2013-12-05

Posts: 1

Screen blacks out after adjusting backlight

Hi, New to Arch but have been using Linux for quite some time.

I am having a very odd problem with my laptop's backlight.  After adjusting the backlight with the function keys, my screen will go black with a few random color blocks (it happens when I turn the brightness down very low, then try to turn it back up).  I can't recover from this and have to restart the laptop using the power button.  I had no issues with Windows, OpenSUSE, and Fedora. 

Possible theory:  I am thinking maybe the function key, on the other OSs, had a binding and adjust the backlight through an OS function, but with no key binding, its being passed on to some piece of hardware...but I have no clue.

This doesn't happen if I adjust it using dell_backlight or radeon_b10.
here is my backlight directory (acpi_video0 turned into dell_backlight after adding acpi_osi=Linux acpi_backlight=vendor to the kernel parameters)

[22:14][ygamal:/sys/class/backlight]$ ls -al
total 0
drwxr-xr-x  2 root root 0 Dec  4 21:57 .
drwxr-xr-x 43 root root 0 Dec  4 21:57 ..
lrwxrwxrwx  1 root root 0 Dec  4 22:14 dell_backlight -> ../../devices/platform/dell-laptop/backlight/dell_backlight
lrwxrwxrwx  1 root root 0 Dec  4 22:14 radeon_bl0 -> ../../devices/pci0000:00/0000:00:01.0/0000:02:00.0/drm/card0/card0-LVDS-1/radeon_bl0

Video Card (xf86-video-ati driver):

[22:18][ygamal:/sys/class/backlight]$ lspci | grep VGA
02:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Park [Mobility Radeon HD 5430/5450/5470]

xbacklight:

[22:24][ygamal:/sys/class/backlight]$ xbacklight
No outputs have backlight property

Does anyone know the default function key behavior in arch?  I think its possible I could bind the function key to adjust one of the backlight drivers and be done with this, but I am curious what is going on.  Thanks for any help!

Last edited by Seefo (2013-12-05 02:37:53)