Red Hat Bugzilla – Bug 183269
powernow-k8 cpu scaling not working
Last modified: 2015-01-04 17:25:40 EST
Description of problem:
I am using the 32bit version of FC5t3 and CPU scaling doesn't work. This is a
very painful bug.
Version-Release number of selected component (if applicable):
kernel-2.6.15-1.1977_FC5 & kernel-2.6.15-1.1955_FC5
Steps to Reproduce:
1. Boot listed kernel
2. dd if=/dev/urandom of=/dev/null
3. noticed unchanged cpu speed
scaling doesn't happen
cpu scales up to maximum speed
Feb 25 15:06:12 vision kernel: powernow-k8: Found 1 AMD Athlon 64 / Opteron
processors (version 1.60.0)
Feb 25 15:06:12 vision kernel: powernow-k8: 0 : fid 0xe (2200 MHz), vid 0x2
Feb 25 15:06:12 vision kernel: powernow-k8: 1 : fid 0xa (1800 MHz), vid 0xa
Feb 25 15:06:12 vision kernel: powernow-k8: 2 : fid 0x0 (800 MHz), vid 0x12
Feb 25 15:06:12 vision kernel: cpu_init done, current fid 0x0, vid 0x12
Feb 25 15:06:15 vision kernel: powernow-k8: vid trans failed, vid 0x11, curr 0x12
Feb 25 15:06:15 vision kernel: powernow-k8: transition frequency failed
Feb 27 09:33:13 vision kernel: Initializing CPU#0
Feb 27 09:33:13 vision kernel: CPU 0 irqstacks, hard=c03c5000 soft=c03c4000
Feb 27 09:33:13 vision kernel: PID hash table entries: 4096 (order: 12, 65536 bytes)
Feb 27 09:33:13 vision kernel: Detected 798.036 MHz processor.
Feb 27 09:33:13 vision kernel: CPU: AMD Athlon(tm) 64 Processor 3400+ stepping 0a
Looking at /boot/config* for both kernels, I now see that powernow-k8 (and most
other scaling code) is disabled. What the heck?! Please, please, please, please,
please ship a kernel with scaling support. Having a severely crippled cpu is not
Just to be absolutely clear, my processor is stuck at its lowest frequency.
are you running the 586 version of the kernel ?
It's set to =y in the 686, 686-smp & x86-64 kernels.
Sure enough, I had a 586 kernel. I reinstalled to see if it happened again. This
time I have a 686 kernel and cpu scaling is working. One difference is that I
installed rawhide instead of test 3.