Messages in this thread | | | Subject | cpufreq regression, unable to set lower frequency | From | Martin Filip <> | Date | Thu, 21 Aug 2008 19:51:41 +0200 |
| |
Hi LKML,
I've upgraded my kernel few days earlier and suddenly my cpufreqd stopperd working. My configuration is this: AC adapter connected: set scaling_max_freq and scaling_min_freq to maximal available frequency AC adapter disconnected: set scaling_max_freq to maximal available, scaling_min_freq to minimal available.
When I connect AC adapter, everything works fine but when I disconnect my adapter, everything remains on maximal frequency and in logs I can see:
cpufreqd: cpufreqd_set_profile: Couldn't set profile "Powersave Low" set for cpu0
After some tests I've traced problem to
http://git.kernel.org/?p=linux/kernel/git/stable/linux-2.6.25.y.git;a=commitdiff;h=53391fa20cab6df6b476a5a0ad6be653c9de0c46
What do you think? Is this condition correct?
# cd /sys/devices/system/cpu/cpu0/cpufreq/
when AC adapter is connected, something like this should happen: # cat scaling_available_frequencies 2167000 2000000 1833000 1667000 1500000 1333000 1000000 # echo 2167000 > scaling_max_freq # echo 2167000 > scaling_min_freq
when disconnected, something like this should: # echo 1000000 > scaling_max_freq -su: echo: write error: Invalid argument # echo 1000000 > scaling_min_freq
after min is set, max can be lowered to. Before this patch, lowering max below min lead to lowering of min to the same value.
I think that this whole condition must not be here at all. After removing this condition the kernel behaves like this:
# cat scaling_min_freq scaling_max_freq 2167000 2167000 # echo 1000000 > scaling_max_freq # cat scaling_min_freq scaling_max_freq 1000000 1000000 # echo 2167000 > scaling_min_freq # cat scaling_min_freq scaling_max_freq 1000000 1000000 # echo 2167000 > scaling_max_freq # echo 2167000 > scaling_min_freq # cat scaling_min_freq scaling_max_freq 2167000 2167000
Which I think is not perfect but is better then current behavior. What do you think?
-- Martin Filip <bugtraq@smoula.net> jabber: nexus@smoula.net [unhandled content-type:application/pgp-signature] | |