Second CPU core loses frequency scaling on resume

[none]

Binary package hint: linux-source-2.6.24

I recently installed Hardy Alpha 4 on my Inspiron 1420 Intel Dual Core machine.

Resume from suspend-to-ram, works fine for the most part except that the second CPU core loses frequency scaling (and goes to maximum frequency):

# find /sys/ -iname \*cpufreq\*
/sys/devices/system/cpu/cpu0/cpufreq
/sys/module/cpufreq_ondemand
/sys/module/cpufreq_powersave
/sys/module/cpufreq_userspace
/sys/module/cpufreq_stats
/sys/module/cpufreq_conservative
/sys/module/acpi_cpufreq

Note the absence of /sys/devices/system/cpu/cpu1/cpufreq . I have not found any way to recover from this, other than a reboot.

[none (ubuntu-bugs-nullinfinity-deactivatedaccount)]

I see now that the absence of /sys/devices/system/cpu/cpu1/cpufreq is a red herring - that's not there on the first boot either, when the frequency on the second core does scale correctly. I'll look into this some more...

[none (ubuntu-bugs-nullinfinity-deactivatedaccount)]

The second core does go to 100% CPU frequency on resume. Top reports no load on the system and /proc/interrupts looks fairly evenly balanced between the cores. It seems that /sys/devices/system/cpu/cpu1/cpufreq not being there makes powernowd unhappy though:

# /etc/init.d/powernowd restart
 * Stopping powernowd: [ OK ]
 * Starting powernowd... /etc/init.d/powernowd: 175: cannot create /sys/devices/system/cpu/cpu1/cpufreq/scaling_governor: Directory nonexistent
                                                                         [fail]

[none (ubuntu-bugs-nullinfinity-deactivatedaccount)]

... and also, please ignore comment number five about /sys/devices/system/cpu/cpu1/cpufreq not existing on cold boot - it *does* exist.

So the root cause of the problem does seem to be that cpufreq no longer wants to talk to the second core on resume.