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get second cpu core enabled after s2ram suspend

September 1st, 2009 Comments off

Time of holidays is out, time to get back to work. So I have started back work, but one thing made me curious – second core of my CPU was shown as off after resuming from suspend.

Checking CPU state through /sys/devices/system/cpu/cpu1/online shows 1 so the cpu is up, but it has no frequency – this is quite weird.
After some searching I have found that this is probably bug in kernel, another day I have found out that reloading module acpi_cpufreq should resolve this issue and it really did.

Knowing what is the reason I have started thinking how to make the process more automatic, so it is quite easy, just modify /usr/lib/pm-utils/defaults – in variable SUSPEND_MODULES add acpi_cpufreq like this:

SUSPEND_MODULES=”acpi_cpufreq”

Now after resume I can see back my cpu frequency, hope you can too.

By the way I see that /usr/lib/pm-utils/defaults is very important, I have to find a way to make editing it more convenient.

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