https://bugzilla.kernel.org/show_bug.cgi?id=48721 Summary: acpi_cpufreq can't change CPU clock anymore Product: Power Management Version: 2.5 Kernel Version: 3.6.1 Platform: All OS/Version: Linux Tree: Mainline Status: NEW Severity: normal Priority: P1 Component: cpufreq AssignedTo: cpufreq@xxxxxxxxxxxxxxx ReportedBy: mavoga@xxxxxxxxx Regression: Yes Created an attachment (id=83121) --> (https://bugzilla.kernel.org/attachment.cgi?id=83121) 3.5.5 kernel: output of 'grep -r . /sys/devices/system/cpu/ 2>/dev/null' On my laptop (a Clevo W150HRM with an i7 2720QM CPU) I'm currently running Debian wheezy/sid with latest aptosid (3.6-1.slh.3) amd64 kernel: after switching from 3.5.5 to 3.6 kernel I noticed the idle temperatures suddenly increased by ~10°C with no apparent activity on the system. The temperature increase, together with sysfs scaling_cur_freq and cpuinfo_cur_freq values seem to support my suspect of a cpufreq bug: the ondemand governor doesn't seem able to modulate the CPU clock anymore. While the scaling_cur_freq value varies depending on system load just as expected, the cpuinfo_cur_freq value remains stuck at (or over because of turbo boost) the maximum CPU frequency, just like the performance governor was set. I could get the same frequency readings with cpufreq-info, turbostat and i7z: the CPU frequency never decreases under 2.2GHz. Furthermore, no cpufreq-set setting seems able to lower the idle frequency in any way, even by changing governor, and a test 3.6.1 vanilla kernel I compiled for testing purposes showed the same behavior. As soon as I reboot to a 3.5.5 kernel cpuinfo_cur_freq begin to follow scaling_cur_freq just as expected, and the idle temps decrease back by over 10°C. -- 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
