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Old 09-16-08, 10:38 PM   #1
dejuren
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Join Date: Sep 2008
Posts: 3
Default Backlight is not ajustable in Ubuntu 8.04 and 8.10 alpha

We are testing two high end notebooks with nVidia 9800M GT cards. Brightness hot keys don't work and possible brightness levels are not available on either system.

ls /proc/acpi/video/

--- directory is empty

ls /sys/class/backlight/

--- directory is empty

Brightness can be adjusted in the BIOS and Windows on one system and only in Windows on the second.

Tested 8.04.1 with the latest kernel and Intrepid with 2.6.27-2 and 2.6.27-3.

acpi will dim the display to sleep when inactive.

With nvidia-settings color brightness can be adjusted but not the backlight.

The brightness can not be adjusted in kpowersave either. It says the "Your hardware currently does not support changing the brightness on your display". This is the same as gnome brightness panel applet. I think it's due to the inability to read LCD brightness data from /proc and /sys interfaces.
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