Random change of Screen brightness

[mbp0392]

I have Triple boot of Mac OS X, Win XP and Ubuntu (8.10)
My laptop is Macbook Pro 4,1
I can control brightness in ubuntu and it works well, however I notice at times that the brightness sometimes goes down one level. I know this because frequently I put the lowest possible level of brighness above complete dark screen and my screen goes dark and I have to manually put it above the minimum (2 more). Then at another undetermined time it goes back up again.
In fact just now typing this bug report the brightness went up.

[Bryce Harrington (bryce)]

Hi gusgl2001,

Please attach the output of `lspci -vvnn`, and attach your /var/log/Xorg.0.log file from after reproducing this issue. If you've made any customizations to your /etc/X11/xorg.conf please attach that as well.

Please attach the output of `lspci -vvnn` too.

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[eugeniolevi (euglevi)]

I have more or less the same problem. I have a Pc, not a laptop, with Ubuntu 8.10, Radeon X600. In my computer too, the monitor has a problem in mantaining brightness stability. It randomly changes in the first 10 minutes of activity of the computer, going down. I attach the lspci output and the Xorg.0.log.