[Bug 77201] CPU online hangs, works when powernow-k8 is UN-loaded

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https://bugzilla.kernel.org/show_bug.cgi?id=77201

--- Comment #12 from Srivatsa S. Bhat <srivatsa@mit.edu> ---

Hi,

I took a quick look at the CPU hotplug path in both cpufreq.c and
powernow-k8.c, but nothing really appeared to stand out.

Does reverting commit c3274763bfc (cpufreq: powernow-k8: Initialize per-cpu
data-structures properly) help? I just want to know if that is a suspect or
not, since that commit went in around 3.14 and is the only relevant commit in
powernow-k8 driver during that time. I'll attach the reverted patch with this
bugzilla for your reference.

Also, please give the output of:
cat /sys/devices/system/cpu/cpuNum/cpufreq/related_cpus
cat /sys/devices/system/cpu/cpuNum/cpufreq/affected_cpus

for both CPUs 0 and 1 (just replace cpuNum with 0 and 1).

One other thing: what is the exact version of the earliest failing kernel? Is
it vanilla 3.14 or a stable version of 3.14 (eg: 3.14.x)? (For pass/fail
testing, please use the sysfs method with powernow-k8 loaded, like you did in
comment 7. Once we get this fixed, you can try the full suspend/resume tests).

Thank you!

Regards,
Srivatsa S. Bhat

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