I have a Mobility Radeon X1400 (RV500 Family) on my dell inspiron 6400 (or it's called inspiron 1501 or 1505 elsewhere). I use Open-source drivers and they work for me and I have no problem with anything except the powermanagement at kernel level. When I want to activate powersaving feature I use these commands: 1. when I use this command: echo dynpm > /sys/class/drm/card0/device/power_method nothing happens. I mean GPU frequency remain high. I even do not use a GUI. I'm in the shell. 2. when I use these commands echo profile > /sys/class/drm/card0/device/power_method echo low > /sys/class/drm/card0/device/power_profile I receive these error: Message from syslogd@keivan-laptop at Aug 9 16:41:37 ... kernel:[ 192.253008] NMI: PCI system error (SERR) for reason b1 on CPU 0. Message from syslogd@keivan-laptop at Aug 9 16:41:37 ... kernel:[ 192.253016] Dazed and confused, but trying to continue after a few seconds if I continue to work system freezes. I've tested this in different distribution of GNU/Linux with different kernel versions: Including LMDE, Archlinux and Chakra. with these kernel versions: 2.6.38, 2.6.39, 3.0.0 RC5, and lately with 3.0.0-1-amd64 in LMDE. I asked this question in LMDE forums here http://forum.linuxmint.com/viewtopic.php?f=141&t=75962&p=440838
I still have this problem in linux kernel 3.4.55 in ubuntu 12.04.2 - When I activate dynpm kernel craches. - In the profile mode also I get the same error as I did before. I have noticed that the kernel do not changes the GPU and Vram frequencies correctly in the profile mode. This is what I get when I set it to mid: # echo mid > /sys/class/drm/card0/device/power_profile # cat /sys/kernel/debug/dri/0/radeon_pm_info default engine clock: 432000 kHz current engine clock: 209250 kHz default memory clock: 396000 kHz current memory clock: 135000 kHz PCIE lanes: 1 This is what I get when I set it to low: # echo low > /sys/class/drm/card0/device/power_profile # cat /sys/kernel/debug/dri/0/radeon_pm_info default engine clock: 432000 kHz current engine clock: 324000 kHz default memory clock: 396000 kHz current memory clock: 135000 kHz PCIE lanes: 1 This is what I get when I set it to high: # echo high > /sys/class/drm/card0/device/power_profile # cat /sys/kernel/debug/dri/0/radeon_pm_info default engine clock: 432000 kHz current engine clock: 432000 kHz default memory clock: 396000 kHz current memory clock: 396000 kHz PCIE lanes: 0 If you look at the above values, it is obvious that the default clock of mid and low should be replaced with each other.
Editing a bug. I'm very sorry for the noise.