On Fri, 2009-03-06 at 15:30 -0800, Andrew Morton wrote: > (switched to email. Please respond via emailed reply-to-all, not via the > bugzilla web interface). > > On Fri, 6 Mar 2009 05:21:50 -0800 (PST) > bugme-daemon@xxxxxxxxxxxxxxxxxxx wrote: > > > http://bugzilla.kernel.org/show_bug.cgi?id=12826 > > > > Summary: cpufreq driver do not expose all data and configuration > > to /sys > > Product: Power Management > > Version: 2.5 > > KernelVersion: 2.6.29-rc7 > > Platform: All > > OS/Version: Linux > > Tree: Mainline > > Status: NEW > > Severity: normal > > Priority: P1 > > Component: cpufreq > > AssignedTo: cpufreq@xxxxxxxxxxxxxxx > > ReportedBy: uzytkownik2@xxxxxxxxx > > > > > > Latest working kernel version: 2.6.28 > > Earliest failing kernel version: 2.6.29-rc7 (also -rc5 and -rc6 but tested only > > with patchset) > > Distribution: Gentoo > > Hardware Environment: Thinkpad R51e > > Software Environment: Standard stack (although reproduced with only /bin/sh as > > init) > > Problem Description: > > Contrary to documentation there are little files controlling the cpufreq > > > > # ls /sys/devices/system/cpu/cpu0/cpufreq/ > > conservative stats > > # ls /sys/devices/system/cpu/cpu0/cpufreq/conservative > > down_threshold ignore_nice_load sampling_rate sampling_rate_min > > freq_step sampling_down_factor sampling_rate_max up_threshold > > > > Steps to reproduce: > > Boot > > I'd say that > > commit 8529154ec3f3ac20344c65b7a040c604c7af7651 > Author: Herton Ronaldo Krzesinski <herton@xxxxxxxxxxxxxxx> > Date: Sat Nov 15 17:02:46 2008 -0200 > > [CPUFREQ] Add Celeron Core support to p4-clockmod. > > has a good chance of being the cause of this regression? Unfortunately I reverted this commit and it had no effect. However I found however commit: commit e088e4c9cdb618675874becb91b2fd581ee707e6 Author: Matthew Garrett <mjg@xxxxxxxxxx> Date: Tue Nov 25 13:29:47 2008 -0500 [CPUFREQ] Disable sysfs ui for p4-clockmod. p4-clockmod has a long history of abuse. It pretends to be a CPU frequency scaling driver, even though it doesn't actually change the CPU frequency, but instead just modulates the frequency with wait-states. The biggest misconception is that when running at the lower 'frequency' p4-clockmod is saving power. This isn't the case, as workloads running slower take longer to complete, preventing the CPU from entering deep C stat es. However p4-clockmod does have a purpose. It can prevent overheating. Having it hooked up to the cpufreq interfaces is the wrong way to achieve cooling however. It should instead be hooked up to ACPI. This diff introduces a means for a cpufreq driver to register with the cpufreq core, but not present a sysfs interface. I guess lack of sysfs ui is the problem (at lest AFAIU 'sysfs ui'). However lack of sysfs ui prevents the cpufreq from lowering frequency on overheat[1]. I'll try tomorrow (well. today morning) if this commit causes it. While I understend that the p4-clockmod shouldn't be used no other driver is working. p4-clockmod is recommend on thinkwiki[2]. All I found is a post from 2006 mentioning there is a patch for speedstep driver which the author is going to try in a spare time - but p4-clockmod is working. So there are no known replacements for them. Regards PS, Even if the commit will not be reverted documentation should be updated. For example in help of p4-clockmod the change should be mentioned. [1] I'd find out the problem if the system didn't started to overheat. Something is wrong but lowering the 'frequency' drop the temperature only by 20 degrees (from 9x to 7x). [2] http://www.thinkwiki.org/wiki/Intel_Celeron_M#Speed_Step
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