I had the CPU frequency scaling working fine on my AMD Turion-based laptop running SuSE 9.3 and then suddenly it started to freeze every now and again. So I tried to reboot and now powersave still does not work. These are the starup messages after reboot: --<snip>-- Sep 24 20:23:07 fullyautomatix kernel: powernow-k8: Found 1 AMD Athlon 64 / Opteron processors (version 1.00.09e) Sep 24 20:23:07 fullyautomatix kernel: powernow-k8: 0 : fid 0xa (1800 MHz), vid 0x4 (1450 mV) Sep 24 20:23:07 fullyautomatix kernel: powernow-k8: 1 : fid 0x8 (1600 MHz), vid 0x6 (1400 mV) Sep 24 20:23:07 fullyautomatix kernel: powernow-k8: 2 : fid 0x0 (800 MHz), vid 0x16 (1000 mV) Sep 24 20:23:07 fullyautomatix kernel: powernow-k8: failing init, change pending bit set Sep 24 20:23:07 fullyautomatix [powersave][6915]: WARNING in Function getSupportedSleepStates; line 21: Could not open /proc/acpi/sleep file to evaluate supported sleeping states --<snip>--

Any idea what could cause this?

We've started seeing this internally in AMD QA. The bit that the processor uses to indicate that it is in the process of changing frequencies (aka the pending change bit) is not clearing. The powernow-k8 driver cannot change frequencies until the previous change has completed.

Because this is happening on the hardware side, my best guess is that the problem is not software related. We've reported the problem to the AMD hardware debug team and they're investigating. I'll put out a patch when we have a solution.

-Mark Langsdorf AMD, Inc.