[gma900] screen flickers for 2-3 minutes and getting almost black when unpluging laptop

[Christian Göbel]

Binary package hint: xserver-xorg-video-intel

I am testing the development version of Ubuntu 9.04 (jaunty) alpha 6 and latest updates.
This bug has been discovered on a 3 year old Samsung laptop with a 1400x1050 screen resolution and
a Intel-Centrino platform.
Previous versions of Ubuntu (8.04 and 8.10) did not show this behaviour.

Whenever I un-plug the power-plug form the laptop, the screen of the laptop is flickering heavily for 2-3 minutes.
To me it seems that the laptop is constantly trying to set the mod for the screen.
After a while the screen is dimed down to an almost black screen. When trying to get a brighter screen via the function keys I still can't get to a usable brightness (the screen stays very dark).

After 2-3 minutes the screen stops flickering but stays very dark.

The attached log-files are produced by unplugging the power supply and pluging in again (after 5 seconds). Even in this case the screen is flickering for aprox. 30 seconds.

I get similar behaviour when logging into gnome on battery.

[Geir Ove Myhr (gomyhr)]

There is a similar (but maybe not exactly the same) problem at bug 339200.

From you log file it seems that you also have something calling an Xrandr method over and over again (your Xorg.0.log is BIG, with the same lines over and over again in the end -- the lines are added each time Xrandr is called). On many monitors each Xrandr call may cause a blink, and this is perfectly normal. The unnatural thing here (like in bug 339200) is that something is triggering this constantly.

You can keep an eye on the number of lines in Xorg.0.log by running `while true; do wc -l /var/log/Xorg.0.log; done` before you unplug the power (stop it with Ctrl+C). You should see the same number until the Xrandr starts adding lines. On my computer, running xrandr once from the command line adds about 100 lines.

To solve this problem, we have to figure out what program is calling xrandr constantly. Could you try logging in with different window managers (KDE, gnome, xfce, etc.) and see if this changes the behaviour?

[Christian Göbel (christiangoebel)]

I am the original reporter of the bug.
It seems that my problems with respect to flickering have been solved with one of the recent updates.
However when I unplug the power-cable my monitor still goes almost black and I cannot achieve a satisfying bright monitor by using the function keys.
With Ubuntu 8.10: When unplugging the power cable the monitor goes a bit darker - and can be re-adjusted manually.
With Jaunty beta: When unplugging the power cable the monitor goes almost black - and can be adjusted only within darker bounds.

From a users point of view It seems that two mechanisms (to lower the brightness of the screen) are applied at the same time.
Could this problem be related to the intel-drivers?
Should I close this bug - and open a new one with the remaining issue?

[Geir Ove Myhr (gomyhr)]

> Should I close this bug - and open a new one with the remaining issue?

Yes, please :-)