acpi video module prevents brightness adjusting

I can confirm this problem on my Dell Inspiron 9400. A solution is to add the line "alias video off" to /etc/modprobe.d/local

Correction: my experience is a little different. I have logged it as Bug #71433.

Check to make sure your BIOS is up-to-date. It can be that this is because the ACPI on your machine is broken, but I wont rule out a bug in the acpi video driver.

My BIOS is up to date. The problem is that the function "acpi_video_get_next_level" in video.c is not implemented in version 2.6.17 (reference: http://lkml.org/lkml/2006/11/24/131). I think the function has been implemented in version 2.6.19 (reference: http://kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.19-rc6/2.6.19-rc6-mm2/patch-list).

Bug confirmed also on my machine: Dell Inspiron 6400.
I've also compiled kernel 2.6.19 and the bug is still present in the video module.

The problem remains after updating my BIOS to the latest version (A05).

[Expired for linux-source-2.6.17 (Ubuntu) because there has been no activity for 60 days.]

I have DELL INSPERON 6400, I upgrade to Guesty today and now I can't change the screen brightness.
It is work perfectly in Feisty.

Hi Juan, now that the 7.10 Gutsy Gibbon release of Ubuntu is out, we were wondering if you can still reproduce this issue as well. Could you please download and try the new version of Ubuntu from http://www.ubuntu.com/getubuntu/download and report back your results. If the issue is still present in the new release, does blacklisting the module still work as a valid workaround? Thanks again and we appreciate your help and feedback.

It is work for me now.

Did you do any update to fix this?

It's still reproducible. That is, I can't adjust brightness using hotkeys after acpi video module is loaded (assuming gnome-power-manager is not currently loaded).
Blacklisting the video module is still a valid workaround.
It has also been reported as bug #140782, but it has been incorrectly assigned to kde. Comment <https://bugs.launchpad.net/ubuntu/+source/kdebase/+bug/140782/comments/20> has another valid workaround.

"
It is work for me now.

Did you do any update to fix this?
"

That is because I move to GNOME and it is working only in GNOME and not KDE.

Nadav, it's working for you because gnome-power-manager is changing your brightness. If you "sudo killall gnome-power-manager", then you'll not be able to change brightness using hotkeys. However, if you blacklist the acpi module, you'll be able to change brightness using hotkeys even after you kill gnome-power-manager (because Dell laptops don't need any software to do it).

Hi Juan,

Thanks for your update. I'm retargeting this bug towards the upcoming Hardy kernel. I've tagged this as "hardy-kernel-candidate" so that we make sure to retarget this report once the new release is out. However against the linux-source-2.6.22 package this is being marked as "Won't Fix" as it does not meet the criteria for a stable release update. To learn more about the stable release update process please refer to https://wiki.ubuntu.com/StableReleaseUpdates . Thanks!

Hardy Heron Alpha2 was recently released. It contains an updated version of the kernel. You can download and try the new Hardy Heron Alpha2 release from http://cdimage.ubuntu.com/releases/hardy/alpha-2/ . You should be able to then test the new kernel via the LiveCD. If you can, please verify if this bug still exists or not and report back your results. General information regarding the release can also be found here: http://www.ubuntu.com/testing/hardy/alpha2 . Thanks!

Over 4 months with no response. We are closing this bug report because it lacks the information we need to investigate the problem, as described in the previous comments. Please reopen it if you can give us the missing information, and don't hesitate to submit bug reports in the future. To reopen the bug report you can click on the current status, under the Status column, and change the Status back to "New". Thanks again!

Oops, sorry for my late reply.

I'm running an up-to-date Hardy clean install, and I'm still experiencing this bug. That is, after the video module is loaded, I can't change brightness with Fn keys without gnome-power-manager (but my Dell laptop do this by hardware!). Also, with the video module loaded, I'm experiencing bug #207473. You can see my "lshal" and "lshal -m" output at <https://bugs.launchpad.net/ubuntu/+source/hal/+bug/207473/comments/19>.

However, by not loading the video module (blacklisted), I can change brightness when g-p-m is not loaded, and when g-p-m is loaded I don't experience bug #207473. You can see my "lshal" and "lshal -m" output with video module blacklisted at <https://bugs.launchpad.net/ubuntu/+source/hal/+bug/207473/comments/32>.

Hi Juan,

Per the kernel team's bug policy, can you please attach the following information. Please be sure to attach each file as a separate attachment.

* uname -a > uname-a.log
* cat /proc/version_signature > version.log
* dmesg > dmesg.log
* sudo lspci -vvnn > lspci-vvnn.log

For more information regarding the kernel team bug policy, please refer to https://wiki.ubuntu.com/KernelTeamBugPolicies . Thanks again and we appreciate your help and feedback.

Hi Juan,

It unfortunately looks like this didn't get resolved for the Hardy release. Care to just confirm this is still an issue with the upcoming Intrepid Ibex 8.10 release? More information regarding the latest Alpha release for Intrepid can be found here - http://www.ubuntu.com/testing . You should be able to test via a LiveCD. Please let us know your results. Thanks.

It looks like it has been solved in Hardy: when acpi video module is loaded, I can change brightness using hotkeys even if g-p-m is not loaded.

Thanks for the feedback Juan. I'll go ahead and mark this "Fix Released" per you last comment.

I'm sorry, I meant Intrepid instead of Hardy in my last comment (comment #24).