Bug 758755

Summary: CPU always on lowest frequency when on battery
Product: [Fedora] Fedora Reporter: Rui Matos <tiagomatos>
Component: kernelAssignee: Kernel Maintainer List <kernel-maint>
Status: CLOSED INSUFFICIENT_DATA QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: 15CC: gansalmon, itamar, jonathan, kernel-maint, madhu.chinakonda
Target Milestone: ---   
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2012-06-07 15:12:48 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:

Description Rui Matos 2011-11-30 16:33:39 UTC
Using the kernel 2.6.41.4-1.fc15.x86_64 it seems that whenever I boot my laptop on battery power the CPU never gets out of the lowest frequency.

$ sudo grep "" /sys/devices/system/cpu/cpu0/cpufreq/*
[sudo] password for rui: 
/sys/devices/system/cpu/cpu0/cpufreq/affected_cpus:0
/sys/devices/system/cpu/cpu0/cpufreq/bios_limit:2001000
/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq:800000
/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq:2001000
/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_min_freq:800000
/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_transition_latency:10000
/sys/devices/system/cpu/cpu0/cpufreq/related_cpus:0 1
/sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies:2001000 2000000 1600000 1200000 800000 
/sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors:ondemand userspace performance 
/sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq:800000
/sys/devices/system/cpu/cpu0/cpufreq/scaling_driver:acpi-cpufreq
/sys/devices/system/cpu/cpu0/cpufreq/scaling_governor:ondemand
/sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq:800000
/sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq:800000
/sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed:<unsupported>



Here's how powertop's frequency stats looks:

            Package |            CPU 0
Turbo Mode   0,0%   | Turbo Mode   0,0%
2,00 Ghz     0,0%   | 2,00 Ghz     0,0%
1,60 Ghz     0,0%   | 1,60 Ghz     0,0%
1200 Mhz     0,0%   | 1200 Mhz     0,0%
 800 Mhz     0,0%   |  800 Mhz     0,0%
Idle	   100,0%   | Idle	 100,0%

                    |            CPU 1
                    | Turbo Mode   0,0%
                    | 2,00 Ghz     0,0%
                    | 1,60 Ghz     0,0%
                    | 1200 Mhz     0,0%
                    |  800 Mhz     0,0%
                    | Idle	 100,0%



$ cat /proc/cpuinfo 
processor	: 0
vendor_id	: GenuineIntel
cpu family	: 6
model		: 15
model name	: Intel(R) Core(TM)2 Duo CPU     T7300  @ 2.00GHz
stepping	: 10
cpu MHz		: 800.000
cache size	: 4096 KB
physical id	: 0
siblings	: 2
core id		: 0
cpu cores	: 2
apicid		: 0
initial apicid	: 0
fpu		: yes
fpu_exception	: yes
cpuid level	: 10
wp		: yes
flags		: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm constant_tsc arch_perfmon pebs bts rep_good nopl aperfmperf pni dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm lahf_lm ida dts tpr_shadow vnmi flexpriority
bogomips	: 3988.73
clflush size	: 64
cache_alignment	: 64
address sizes	: 36 bits physical, 48 bits virtual
power management:

processor	: 1
vendor_id	: GenuineIntel
cpu family	: 6
model		: 15
model name	: Intel(R) Core(TM)2 Duo CPU     T7300  @ 2.00GHz
stepping	: 10
cpu MHz		: 800.000
cache size	: 4096 KB
physical id	: 0
siblings	: 2
core id		: 1
cpu cores	: 2
apicid		: 1
initial apicid	: 1
fpu		: yes
fpu_exception	: yes
cpuid level	: 10
wp		: yes
flags		: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm constant_tsc arch_perfmon pebs bts rep_good nopl aperfmperf pni dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm lahf_lm ida dts tpr_shadow vnmi flexpriority
bogomips	: 3988.87
clflush size	: 64
cache_alignment	: 64
address sizes	: 36 bits physical, 48 bits virtual
power management:

Comment 1 Dave Jones 2011-11-30 17:09:49 UTC
Limiting like this usually happens because the BIOS refuses to go higher.
Do the higher frequencies come back again when you plug back in ?