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On my laptop, whenever the computer is idle a period of time (10 minutes I think) the monitor shuts off. At this time the cpu usage spikes, I know this because the fan starts going crazy. When I move the mouse, the process immediately dies and cpu usage returns to normal.

I've tried to monitor what is running using htop and it appears to be compiz, but this could be an artifact of waking up and not what is causing the problem.

I'm running Ubuntu 12.04 and have an ATI graphics card (5400 series I believe). I'm fairly certain the drivers are up to date.

My question: How can I find out what is running? or How can I fix this problem?

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There is a bug report on this here: I think I've had the same issue and my solution was to go into the brightness and lock settings and set the monitor to turn off 'never.' I then manually lock and turn off the monitor with either hot-keys or power button. My work around is not really a solution, though. Just a work around that keeps your fan from going nuts. I hadn't seen the bug report until today, so there might be a workaround or patch to be found somewhere in the launchpad bug thread (I'm saving it for when I'm back home). – user70215 Jun 12 '12 at 20:22
Yes, this bug is exactly what I have. My "solution" was identical to yours. Thanks for the link, they have a work around that I will try. – Mitch Phillipson Jun 14 '12 at 1:07
up vote 1 down vote accepted

You can find out what is running by making a cron job, a scheduled command that runs just before the monitor switches off. See man crontab. You can run top -d 20 > screen.log. This will dump the average of 20 seconds to a file called screen.log. Maybe other logs could be useful such as dmesg. You might want to find out about the behaviour of the fans: I presumed they operated according to temperature but your experience would seem to belie this. Still you can still measure the temperature using lmsensors program.

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Thanks for the help. This shows that compiz is responsible for the cpu spike. Also, the fans are temperature based. – Mitch Phillipson May 8 '12 at 21:06

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