linux-image 2.6.28 backlight control has decrease and increase mixed up

[Khashayar Naderehvandi]

Binary package hint: linux-image-2.6.28-2-generic

With a recent update to kernel 2.6.28 on Jaunty, backlight control on my Asus N20A has it all mixed up. The button to decrease backlight, increases it, and the button to increase it decreases it. Please let me know what additional information would be useful here.

[Khashayar Naderehvandi (khashayar)]

I've found a workaround that might shed some light on the actual problem. If I remove the video module, the Fn-keys start working. On the other hand, gnome-power-manager seems to lose the ability to control the backlight. Reloading the video module again, solves both of these issues (except that the OSD indicating backlight does not appear anymore).

[oCean (alex.harkema)]

I'm on asus x71a. Current kernel is 2.6.28-7-generic. I seem to have same (or similar) problem. Once logged in, screen starts in 'darkest' mode. Using the 'brightness applet' moving the slider to '+' makes screen darker, and to '-' brighter. The Fn button combination 'works', but without steps - It's brightest or darkest, nothing in between.
I'm not sure which video module to unload/reload ?

[oCean (alex.harkema)]

Ah, well. modprobe -r video, and loading it again, indeed does fix the Fn key combination. However, in that case the on-screen-indicator does not show up.

[oCean (alex.harkema)]

my issues continued in: https://bugs.launchpad.net/ubuntu/+source/acpid/+bug/340513

[Jeremy Foshee (jeremyfoshee)]

Hi Khashayar,

This bug was reported a while ago and there hasn't been any activity in it recently. We were wondering if this is still an issue? Can you try with the latest development release of Ubuntu? ISO CD images are available from http://cdimage.ubuntu.com/releases/lucid.

If it remains an issue, could you run the following command from a Terminal (Applications->Accessories->Terminal). It will automatically gather and attach updated debug information to this report.

apport-collect -p linux 305935

Also, if you could test the latest upstream kernel available that would be great. It will allow additional upstream developers to examine the issue. Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Once you've tested the upstream kernel, please remove the 'needs-upstream-testing' tag. This can be done by clicking on the yellow pencil icon next to the tag located at the bottom of the bug description and deleting the 'needs-upstream-testing' text. Please let us know your results.

Thanks in advance.

[This is an automated message. Apologies if it has reached you inappropriately; please just reply to this message indicating so.]

[Khashayar Naderehvandi (khashayar)]

This issue seems to be fixed for me in lucid (unless it was gnome-power-manager specific, as I'm running KDE now).
I'll mark it "fix released".