Can't adjust display brightness

[otkaz]

Ubuntu 10.04 lucid with gnome-power-manager installed on a HP elitebook 8530p. FN keys and desktop display applet will not adjust the display. when I first boot my display is pretty bright with either it plugged into ac or not until i either plug or unplug for the first time then the display dims some, but will not get bright again plugged or unplugged, also /proc/acpi/video/DGFX/LCD/brightness shows it set to 100% at all times it never changes. I'm using the ati driver tried running aticonfig --acpi-services off, but it made no difference. It worked fine in karmic and ibex. I'm out of ideas on how to fix this one. Can anyone point me in the right direction on what to try next?

[LovE-RicH]

I'd just like to say I have the exact same problem on my Ubuntu 10.04 LTS.
However, I turned my laptop off last night and today the brightness is back to normal, but I still can't use the brightness controls.

[nujinini]

I am encountering the same problem lately and have done some research. I think it has something to do with the kernel update?

Kernels 2.6.28xx allows brightness adjustments while 2.6.30xx and above does not. I'm still looking into it though and have not yet reached a definite conclusion. I think its a bug.

[otkaz]

Thanks for the replies. I've seen several bug reports and post about the brightness hot keys not working. Do either of you notice if your brightness dims on the first power state change (plugging power in or unplugging) and will not change back after that? Just wondering if this is part of the same bug, or just an acpi misconfiguration on my computer. I haven't had time to screw with the acpi scripts much, but I did try installing laptop-mode-tools which didn't change anything. I'm gonna try switching to APM to see if its a problem with acpi or not. Let me know if there is anything else I can do to help you track this one down nujinini.

[nujinini]

Do either of you notice if your brightness dims on the first power state change (plugging power in or unplugging) and will not change back after that?

Nope. Not for me. Its consistently bright.

Let me know if there is anything else I can do to help you track this one down nujinini.

Yeah. Thanks! I've been doing some googling and I still have to find a solution. I think the part of the kernel that allows brightness control somehow got lost in the translation I thought I was getting warmer when I found this but I was not successful though. You might want to check it out too.

[all variants] Brightness control in Lenovo G430 - Ubuntu Forums

[SOLVED] Screen brightness does not change on Toshiba Satellite in Karmic - Ubuntu Forums

[hatebreed]

I have the same issue with my acer notebook. I installed 9.10 and the brightness was normal and then I had to add acpi=off in the kernel line because my network card and wireless card didn't load correctly. then I installed the updates and after I rebooted the brightness was dim no matter if I had the power plugged in or not. definately think the acpi is at fault, i've had nothing but issues with it.