laptop panel brightness broke after recent update

[Crazyness]

Recent updates rendered my brightness control via gnome-power-manager unusable. I have no way to controlling the brightness of my screen. whether be it by soft-keys (fn+f7 or fn+f8) or by the Power Manager Brightness Applet in gnome.

attached you'll find my hal_output.txt from issuing the "lshal" command in gnome-temrinal

Unfortunately, i dont remember exactly what packages updated when the bug appeared. If anyone can explain how i might be able to find out, id appreciate it.

Im running Ubuntu 8.10 x86_64 with kernel 2.6.27-11-generic

I expected to have brightness control
But i have no brightness control.

EDIT: This is noted on a ubuntuforums.org thread. http://ubuntuforums.org/showthread.php?t=1036390. Just wanted to tlink the two.

EDIT: Confirmed that the problem lies with the kernel 2.6.27-11.23

[Tim McNamara (tim-clicks)]

Selecting appropriate package.

[minisori (minisori)]

Confirmed, the latest update before these bug, were these:

bind9-host (1:9.5.0.dfsg.P2-1ubuntu3) to 1:9.5.0.dfsg.P2-1ubuntu3.1
dnsutils (1:9.5.0.dfsg.P2-1ubuntu3) to 1:9.5.0.dfsg.P2-1ubuntu3.1
libbind9-40 (1:9.5.0.dfsg.P2-1ubuntu3) to 1:9.5.0.dfsg.P2-1ubuntu3.1
libc6 (2.8~20080505-0ubuntu7) to 2.8~20080505-0ubuntu8
libc6-dev (2.8~20080505-0ubuntu7) to 2.8~20080505-0ubuntu8
libc6-i386 (2.8~20080505-0ubuntu7) to 2.8~20080505-0ubuntu8
libdns43 (1:9.5.0.dfsg.P2-1ubuntu3) to 1:9.5.0.dfsg.P2-1ubuntu3.1
libisc44 (1:9.5.0.dfsg.P2-1ubuntu3) to 1:9.5.0.dfsg.P2-1ubuntu3.1
libisccc40 (1:9.5.0.dfsg.P2-1ubuntu3) to 1:9.5.0.dfsg.P2-1ubuntu3.1
libisccfg40 (1:9.5.0.dfsg.P2-1ubuntu3) to 1:9.5.0.dfsg.P2-1ubuntu3.1
liblwres40 (1:9.5.0.dfsg.P2-1ubuntu3) to 1:9.5.0.dfsg.P2-1ubuntu3.1
linux-headers-2.6.27-11 (2.6.27-11.22) to 2.6.27-11.23
linux-headers-2.6.27-11-generic (2.6.27-11.22) to 2.6.27-11.23
linux-image-2.6.27-11-generic (2.6.27-11.22) to 2.6.27-11.23
linux-libc-dev (2.6.27-11.22) to 2.6.27-11.23
ntpdate (1:4.2.4p4+dfsg-6ubuntu2.1) to 1:4.2.4p4+dfsg-6ubuntu2.2

So may be in the linux kernel update i guess.

[Crazyness (crazyness)]

Well, i got those set of updates a swell. But i also noticed somethign a day earlier:

Commit Log for Wed Jan 7 00:05:37 2009

Upgraded the following packages:
acpi-support (0.114) to 0.114-0intrepid1
....<snipped for irrelevancy>

then

Commit Log for Thu Jan 8 11:30:36 2009

Upgraded the following packages:
libssl0.9.8 (0.9.8g-10.1ubuntu2) to 0.9.8g-10.1ubuntu2.1
linux-headers-2.6.27-11 (2.6.27-11.22) to 2.6.27-11.23
linux-headers-2.6.27-11-generic (2.6.27-11.22) to 2.6.27-11.23
linux-image-2.6.27-11-generic (2.6.27-11.22) to 2.6.27-11.23
linux-libc-dev (2.6.27-11.22) to 2.6.27-11.23
openssl (0.9.8g-10.1ubuntu2) to 0.9.8g-10.1ubuntu2.1

It may be the updated linux kernel or the acpi-support. Those are the only 2 reasons i can think of this happening.

btw: thanks for telling me how to access my history.

[Jerry (priegog)]

I can confirm this bug too.
Using Ubuntu 8.10 32-bits.
Ask for any info that you need.

[Crazyness (crazyness)]

Hey Jerry, did you recently perform an update to the linux headers/image 2.6.27-11.23 or acpi-support?

If you know how to do it, great! If not, just open Synaptic and go to File -> History and look back around January 7th or 8th.

[Jerry (priegog)]

Yup, just did it the day before yesterday. It doesn't make sense to look further back since I've been on vacation and the computer hadn't been used since mid-december... All I know is previously the applet worked, and after the updates, it doesn't. And yes, the updates DID include the new linux headers.

[Crazyness (crazyness)]

The bug is confirmed to appear after a linux-kernel update to 2.6.27-11.23

[Crazyness (crazyness)]

As a suggestion from a post on ubuntuforums.org, I decided to boot into some older kernels i had. Tested on 2.6.27-7 and 2.6.27-10, and in both, the brightness worked. This rules out the ACPI, unless it loaded a different module for those kernels.
Kernel 2.6.27-11.23 is in fact the faulty element in the problem.
 Now, how does one go about to fix this? said the n00b :D

[Tom Vetterlein (smbm)]

For me the opposite is true, brightness worked under 2.6.27-11.23 but not under todays proposed update to 2.6.27-11.24

[Jerry (priegog)]

Finally after today's updates, the brightness applet works again for me.
I think the updates came from intrepid-proposed.
Can the rest of you confirm this?

[Crazyness (crazyness)]

true. Update to intrepid-proposed update solved this.

Commit Log for Fri Jan 16 21:54:45 2009

Upgraded the following packages:
linux-headers-2.6.27-11 (2.6.27-11.23) to 2.6.27-11.24
linux-headers-2.6.27-11-generic (2.6.27-11.23) to 2.6.27-11.24
linux-image-2.6.27-11-generic (2.6.27-11.23) to 2.6.27-11.24
linux-libc-dev (2.6.27-11.23) to 2.6.27-11.24

I tried to update acpi-support and see it it alone would fix, but it didnt
Good Job goes to the devs. Props!

[phorminx (phorminx)]

Yesterday I installed the released 2.6.27-11 kernel (ubuntu 8.10) on my lenovo X300 laptop. With this kernel brightness control is broken for me. I confirmed that brightness control still works with the older 2.6.27-9 kernel. The earlier messages in this thread suggest to me that someone has worked on this problem and the problem has been fixed for some people - but not for me.
Should I report a new bug as the problem is present for me in the released kernel?

[Sukarn Singh Maini (sukarn)]

The kernel might be in the proposed-updates of the mirror you are using as your repository.
Go to System -> Administration -> Software Sources -> Updates
Tick "Pre-released updates"
click close and click reload
install the update to the kernel
turn off the pre-released updates if you want

[phorminx (phorminx)]

Nope, I was pretty sure that I did not have pre-released updates enabled, and that's what I found out by double-checking: for ubuntu updates, I have only "important security updates (intrepid security)" and "recommended updates (intrepid-updates)" enabled. On the other hand "prereleased updates" (and "unsupported updates") are disabled. Doesn't that mean that I installed a "properly released" kernel update or can I not be sure of that? Can I somehow check what actual version of the 2.6.27-11 kernel I am running? In /boot, it's file name is simply vmlinuz-2.6.27-11-generic.

[Sukarn Singh Maini (sukarn)]

I was not telling you to check whether you have pre-released updates enabled, I was telling you to enable them and install the kernel update. Updates are released first in pre-released (proposed-updates) updates and after a certain period of testing they are sent to recommended updates.

[Jakub Hozak (jakub-hozak)]

I am running HP Compaq 6730s with integrated Intel graphics and experience similar problems. My brightness controls doesn't affect the monitor backlight, even if the F7 and F8 keys "work", values in "/proc/acpi/video/GFX0/DD04/brightness" change. I tried any kernel you all suggested, ranging from 2.6.27-7 to 2.6.27-23 but none solved the issue.

Any links or suggestions? Thanks in advance!

[Babar (babarhaq)]

Using X300 started having problem since 2.6.27-11 on intrpid. Upgrade to jaunty running 2.6.27-14 and still facing the same issue. Its a show stopper. Any thing we can do?

[Babar (babarhaq)]

Working fine now on jaunty 2.6.28-11