https://bugzilla.kernel.org/show_bug.cgi?id=16362 --- Comment #3 from timshel@xxxxxxxxxxxxxx 2010-07-11 07:28:45 --- I think I have found the patch causing my issues, at least from the description. I haven't removed and tested it then but it seems obvious: commit e2f74f355e9e2914483db10c05d70e69e0b7ae04 Author: Thomas Renninger <trenn@xxxxxxx> Date: Thu Nov 19 12:31:01 2009 +0100 [ACPI/CPUFREQ] Introduce bios_limit per cpu cpufreq sysfs interface This interface is mainly intended (and implemented) for ACPI _PPC BIOS frequency limitations, but other cpufreq drivers can also use it for similar use-cases. Why is this needed: Currently it's not obvious why cpufreq got limited. People see cpufreq/scaling_max_freq reduced, but this could have happened by: - any userspace prog writing to scaling_max_freq - thermal limitations - hardware (_PPC in ACPI case) limitiations Therefore export bios_limit (in kHz) to: - Point the user that it's the BIOS (broken or intended) which limits frequency - Export it as a sysfs interface for userspace progs. While this was a rarely used feature on laptops, there will appear more and more server implemenations providing "Green IT" features like allowing the service processor to limit the frequency. People want to know about HW/BIOS frequency limitations. All ACPI P-state driven cpufreq drivers are covered with this patch: - powernow-k8 - powernow-k7 - acpi-cpufreq Tested with a patched DSDT which limits the first two cores (_PPC returns 1) via _PPC, exposed by bios_limit: # echo 2200000 >cpu2/cpufreq/scaling_max_freq # cat cpu*/cpufreq/scaling_max_freq 2600000 2600000 2200000 2200000 # #scaling_max_freq shows general user/thermal/BIOS limitations # cat cpu*/cpufreq/bios_limit 2600000 2600000 2800000 2800000 # #bios_limit only shows the HW/BIOS limitation CC: Pallipadi Venkatesh <venkatesh.pallipadi@xxxxxxxxx> CC: Len Brown <lenb@xxxxxxxxxx> CC: davej@xxxxxxxxxxxxxxxxx CC: linux@xxxxxxxxxxxxxxxxxxxx Signed-off-by: Thomas Renninger <trenn@xxxxxxx> Signed-off-by: Dave Jones <davej@xxxxxxxxxx> I am using a Thinkpad so I don't think that the bios is broken and the power management options are default but I am going to adjust them. Atm I have disabled Speedstep in the bios to get the highest frequency with 2.6.34. -- Configure bugmail: https://bugzilla.kernel.org/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are the assignee for the bug. -- 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
