Red Hat Bugzilla – Bug 169290
cpufreq driver not working with em64t processors
Last modified: 2015-01-04 17:22:11 EST
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Description of problem:
Running on an ibm 8843 blade in their bladecenter chassis which has 2 Intel em64t Xeon 3.6ghz processors. I am trying to use cpufreq on_demand govenor. It appears that the kernel does not recognize that the cpu has enhanced speedstep technology and I cannot use cpufreq. There are no entries for cpufreq in /sys/devices/system/cpu subtree for cpufreq. If I look in /proc/cpuinfo I do see the the speedstep flag (est) listed in the flags field so it appears the kernel does know the processor is capable of speedstep. I have also tried vanilla kernels compiled according to intel instructions for enabling speedstep with no luck. Are the em64t processors not supported yet by the kernel or is it some BIOS issue? According to Intel, it should work with kernel version 2.6.9+
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. look in /sys/devices/system/cpu/cpu0 and there is no entry for cpufreq
even the upstream driver still doesn't support speedstep in Xeons.
The best bet right now for these systems is using cpufreq-acpi
Until someone finds out where Intel has hidden the documents detailing the
tables of frequencies these CPUs support, there's not a lot we can do.