Bug 917854

Summary: kernel 3.8 has 50% increase in power consumption
Product: [Fedora] Fedora Reporter: Alessandro Guido <ag>
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: 18CC: gansalmon, itamar, jonathan, kernel-maint, madhu.chinakonda
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Hardware: x86_64   
OS: Unspecified   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
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Clone Of: Environment:
Last Closed: 2013-07-01 13:14:11 UTC Type: Bug
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description Flags
Dmesg 3.7
none
Dmesg 3.8 none

Description Alessandro Guido 2013-03-04 22:48:54 UTC 
With the upgrade to the 3.8 kernel, power consumption on a Dell XPS 14 resulted in an increase of a 50% (and more) when running on battery.

With 3.7, I observed (powertop, all tunings set to "Good") a power usage as low as 8W. With kernel 3.8 I'm not able to get any lower than 14W (and I can hear the fan is always running, while with 3.7 it didn't happen).

Booting with 3.7 restores the good behaviour.

Powertop output looks the same, so I haven't been able to pinpoint the problem more exactly.
Comment 1 Alessandro Guido 2013-03-05 00:05:59 UTC 
Created attachment 705231 [details]
Dmesg 3.7
Comment 2 Alessandro Guido 2013-03-05 00:06:35 UTC 
Created attachment 705232 [details]
Dmesg 3.8
Comment 3 Josh Boyer 2013-04-16 19:43:05 UTC 
If you're still seeing this with 3.8.7, can you please use powertop on both the 3.7 and 3.8 kernels to see if there is a particular device that is causing significantly more wakeups, etc?  There is a known i915 issue with resets in bug 866212 but it's hard to tell if you are seeing that or something else.
Comment 4 Josh Boyer 2013-07-01 13:14:11 UTC 
This bug is being closed with INSUFFICIENT_DATA as there has not been a response in 2 weeks. If you are still experiencing this issue, please reopen and attach the relevant data from the latest kernel you are running and any data that might have been requested previously.