View Full Version : [ubuntu] 2 folders in Sys/Class/Backlight?

January 11th, 2012, 08:34 PM
ISSUE: Backlight brightness does not change.

More Detail: Brightness will not change, using both 'System Settings->Screen', or FN keys (Brightness bar shows and moves, but screen brightness does not change).

Notcied a post in this thread (http://ubuntuforums.org/showthread.php?t=1866283) about having multiple folders in Sys->Class->Backlight...


'intel_backlight' and 'acpi_video0'

Using the function keys, alters the value in the acpi_video0's 'Brightness' file - But doesn't actually alter the brightness of the screen.

If I add 'backlight=vendor' in Grub, my function keys then edit the value in the 'Intel_Backlight brightness file. - But again doesnt actually change the brightness of the screen.

Computer: Fujitsu Siemans Pi2515, Intel Integrated Graphics, No hdd partition.

Already Tried:

-Editing grub to contain: acpi_osi=Linux acpi_backlight=vendor


-sudo apt-get install acpi

-$ sudo setpci -s 00:02.0 F4.B=20

-Brightness does not adjust in fallback mode either. :sad:

-Reinstalling OS, Using Linux Mint (Same problem).

-Upgrading and downgrading BIOS.

Many thanks for reading, I understand this problem may need a bit of a Linux pro to sort. If anyones up for the challenge i'll spend any amount of time being walked through this, posting results. Don't want to give up here! :smile:

January 15th, 2012, 01:49 AM
Unsure of rules, so apologies if Bumps are not allowed. Still got this problem, any help at all would be great, or any words of advice. Many thanks. Zebrapie.

January 15th, 2012, 01:51 AM
No problems with bumps if they are over 24 hour span period - :)

Of course you can respond to answers to your posts at any time.

January 27th, 2012, 06:50 PM
Thank you BlinkinCat :)

Gave up and re-installed Windose, same problem? FFFUUUUUUUUUU Now i'm confused!!