http://bugzilla.kernel.org/show_bug.cgi?id=12826 ------- Comment #7 from anonymous@xxxxxxxxxxxxxxxxxxxx 2009-03-06 18:50 ------- Reply-To: akpm@xxxxxxxxxxxxxxxxxxxx On Sat, 07 Mar 2009 03:39:31 +0100 Maciej Piechotka <uzytkownik2@xxxxxxxxx> wrote: > 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. eh? So we deliberately added a regression? > > 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. Thanks. > 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 > -- Configure bugmail: http://bugzilla.kernel.org/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are the assignee for the bug, or are watching the assignee. -- To unsubscribe from this list: send the line "unsubscribe cpufreq" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
