I tried the rc.local solution and found it not working for some reason (like other common solutions as described here). So I'm posting an alternative solution using pm-utils. I'm not sure if it is the best way to do it (I'm new to Linux) but it does what is necessary: Set the radeon power_profile to low on boot and retain that setting after suspend-resume.
Step 1: Create hook
gksu gedit /usr/lib/pm-utils/power.d/radeon-power_profile
Step 2: Fill in the desired setting
#!/bin/sh
echo profile > /sys/class/drm/card0/device/power_method
echo low > /sys/class/drm/card0/device/power_profile
exit 0
Step 3: Make it executable
sudo chmod +x /usr/lib/pm-utils/power.d/radeon-power_profile
That's it :)
catcommand to see whether your setting is set. Then put the line in/etc/rc.localbefore theexit 0. Here you wantecho "low" > /sys/class/drm/card0/device/power_profileas this script is run by root, so you don't want/needsudo(and anyway this won't work). Then reboot, login and test. – artfulrobot Jun 22 '12 at 10:13ls -l /etc/rc.localare set). Check it is being executed - e.g. put in a line likelogger -t rc.local boo, then reboot, wait 5 mins, login andless /var/log/syslogand search for "rc.local" - the timestamp will show you when it was run. The comments say it runs at end of multiuser boot levels, which means that it should be running by the time you see your login screen. – artfulrobot Jun 22 '12 at 14:41cat /sys/class/drm/card0/device/power_profileit shows high instead of low which for me means that the command is not executed. I did another tutorial link where I made a script that runs on startup but still my power_profile remains in "high" – Tosho Jun 22 '12 at 18:46power_profileis set again tohigh– Tosho Jun 23 '12 at 08:16