backlight throbbing on login & idle

[luke.varnadore]

Binary package hint: gnome-power-manager

The screen brightness jumps back and forth between dim and bright before and after GDM is loaded. I can stop the behaviour by switching to a VT and back when I get to X. And just recently I experienced the problem in bug 289322. I don't know what else I should provide for analysis. Let me know.

ProblemType: Bug
Architecture: i386
Date: Wed Sep 30 22:09:41 2009
DistroRelease: Ubuntu 9.10
Package: gnome-power-manager 2.28.0-0ubuntu1
ProcEnviron:
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcVersionSignature: Ubuntu 2.6.31-11.36-generic
SourcePackage: gnome-power-manager
Uname: Linux 2.6.31-11-generic i686

[luke.varnadore (luke-varnadore)]

Two more things: I have no idea what is causing this - but I noticed a small icon pop up in the gnome-panel tray and tell me to go to this site: http://blogs.gnome.org/hughsie/2009/08/17/gnome-power-manager-and-blanking-removal-of-bodges/.

[luke.varnadore (luke-varnadore)]

This was fixed in my last update/upgrade. Thank you!!!

[luke.varnadore (luke-varnadore)]

Actually I'm lying. The behavior has returned. I don't know why. If there is anything more that I can provide as clues please let me know what it is because it happens every boot.

[luke.varnadore (luke-varnadore)]

I lied again, it doesn't happen every boot. It only happens when I start the laptop without the a/c adapter plugged in. The default behavior when unplugged is to dim the screen and when it tries to do this it jumps between two brightness levels in a loop. This also happens if I increase or decrease brightness by holding down my Fn + Brightness key. If I tap the Fn + Brightness instead of holding it down it will adjust without looping.

[luke.varnadore (luke-varnadore)]

I now have some truth. Blacklisting the uvcvideo kernel module fixes it. I believe this is related strongly to bug #435352.

[luke.varnadore (luke-varnadore)]

I was lying. Don't you get it by now? It fixes the startup issues, but when I change my brightness with my Fn keys the loop starts up again.

[Jorge Juan (jjchico)]

I also face this problem in my MSI Wind U100. This netbook also has bug #435352 but I think the two issues are not related. It happens quite randomly and typically stops when you either switches terminals, login, change brightness, etc. I would say it is just the issue described in

http://blogs.gnome.org/hughsie/2009/08/17/gnome-power-manager-and-blanking-removal-of-bodges/

Since it is quite notorious and is a regression from previous behaviour I would increase the importance of this bug and nominate it for karmic release.

jorge.

[udachee (udachee)]

I have this problem on MSI Wind U100. This bug stays after blacklisting uvcvideo module which solves bug #435352.

[udachee (udachee)]

There are these lines in /var/log/kern.log
Oct 21 11:12:57 u100 kernel: [ 57.646966] integrated sync not supported
Oct 21 11:12:57 u100 kernel: [ 57.798464] integrated sync not supported
Oct 21 11:13:10 u100 kernel: [ 71.445304] integrated sync not supported
Maybe they are related to this problem too.

[Jorge Juan (jjchico)]

Hi!

The only work around I know by now is to switch to a console (Ctrl-Alt-F1), wait for a few seconds and switch back to X (Ctrl-Alt-F7).