Arch Linux

motmaos

Member

Registered: 2010-01-20

Posts: 9

auto dim brightness problem with HP laptop

Hello,
I apologize in advance because I am sure the answer is obvious, yet I cannot find it neither in the forum nor with google. (I have searched for a couple of days before asking)

I have an old HP laptop, 6735s with a radeon hd3200, using catalyst driver.
I have just made a major upgrade after an year or so.

The problem is simple, whatever I do /sys/class/backlight/acpi_video0/actual_brightness always comes back to "0" after a couple of seconds, while /sys/class/backlight/acpi_video0/brightness still shows whatever I write in there, so my lcd brightness is always at the minimum.
Same with xbacklight.
I suppose this is kernel related, because I've just upgraded and this behaviour remains even if I stop laptop-mode and acpid, therefore the brightness value is not changed by them.

Any help would be greatly appreciated, thanks in advance.