[Dell Latitude E6540] CPU stuck on minimum frequency after resume from suspend and unplugged

[Gonçalo Marrafa]

This happens on a Dell Latitude E6540 (4th gen core i7 CPU).

Steps to reproduce:

1) normally boot the computer and make sure everything works as expected (i use the ondemand governor)
2) suspend
3) make the computer is unplugged and resume

Expected behavior: cpu should work normally
Actual behavior: cpu always stays at minimum frequency (in my case 800 MHz)

If i resume from suspend while plugged to the AC charger, everything works as expected.
---
ApportVersion: 2.12.5-0ubuntu2.2
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC1: gjm 2337 F.... pulseaudio
 /dev/snd/controlC0: gjm 2337 F.... pulseaudio
DistroRelease: Ubuntu 13.10
HibernationDevice: RESUME=UUID=98df70b7-f534-4ef6-8647-8e98200ccd64
InstallationDate: Installed on 2013-12-06 (4 days ago)
InstallationMedia: Ubuntu 13.10 "Saucy Salamander" - Release amd64 (20131016.1)
MachineType: Dell Inc. Latitude E6540
MarkForUpload: True
Package: linux (not installed)
ProcFB:
 0 inteldrmfb
 1 radeondrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.11.0-15-generic.efi.signed root=UUID=22510d0e-a296-4b0f-a97a-27cb89a65419 ro quiet splash vt.handoff=7
ProcVersionSignature: Ubuntu 3.11.0-15.23-generic 3.11.10
RelatedPackageVersions:
 linux-restricted-modules-3.11.0-15-generic N/A
 linux-backports-modules-3.11.0-15-generic N/A
 linux-firmware 1.116
RfKill:
 0: phy0: Wireless LAN
  Soft blocked: no
  Hard blocked: no
Tags: saucy
Uname: Linux 3.11.0-15-generic x86_64
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo
dmi.bios.date: 09/03/2013
dmi.bios.vendor: Dell Inc.
dmi.bios.version: A05
dmi.board.name: 0725FP
dmi.board.vendor: Dell Inc.
dmi.board.version: A00
dmi.chassis.type: 9
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.:bvrA05:bd09/03/2013:svnDellInc.:pnLatitudeE6540:pvr01:rvnDellInc.:rn0725FP:rvrA00:cvnDellInc.:ct9:cvr:
dmi.product.name: Latitude E6540
dmi.product.version: 01
dmi.sys.vendor: Dell Inc.

[Brad Figg (brad-figg)]

This bug is missing log files that will aid in diagnosing the problem. From a terminal window please run:

apport-collect 1260112

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

[Gonçalo Marrafa (goncalo-marrafa)]

apport information

[Gonçalo Marrafa (goncalo-marrafa)]

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[Gonçalo Marrafa (goncalo-marrafa)]

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[Gonçalo Marrafa (goncalo-marrafa)]

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[Gonçalo Marrafa (goncalo-marrafa)]

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[Gonçalo Marrafa (goncalo-marrafa)]

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[Gonçalo Marrafa (goncalo-marrafa)]

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[Gonçalo Marrafa (goncalo-marrafa)]

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[Gonçalo Marrafa (goncalo-marrafa)]

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[Gonçalo Marrafa (goncalo-marrafa)]

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[Gonçalo Marrafa (goncalo-marrafa)]

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[Gonçalo Marrafa (goncalo-marrafa)]

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[Gonçalo Marrafa (goncalo-marrafa)]

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[Gonçalo Marrafa (goncalo-marrafa)]

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[Gonçalo Marrafa (goncalo-marrafa)]

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[Joseph Salisbury (jsalisbury)]

Did this issue occur in a previous version of Ubuntu, or is this a new issue?

Would it be possible for you to test the latest upstream kernel? Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v3.12 kernel[0].

If this bug is fixed in the mainline kernel, please add the following tag 'kernel-fixed-upstream'.

If the mainline kernel does not fix this bug, please add the tag: 'kernel-bug-exists-upstream'.

If you are unable to test the mainline kernel, for example it will not boot, please add the tag: 'kernel-unable-to-test-upstream'.
Once testing of the upstream kernel is complete, please mark this bug as "Confirmed".

Thanks in advance.

[0] http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.13-rc3-trusty/

[Gonçalo Marrafa (goncalo-marrafa)]

I can't say if the issue occurs in other versions since the laptop is new and i just installed 13.10 on it. Will test the kernel and update with the results.

[Gonçalo Marrafa (goncalo-marrafa)]

OK, so i tested the 3.13 kernel (3.13.0-031300rc3-generic) and it does _seem_ to make a difference. The problem is that the ondemand cpu governor is not available, only powersave and performance so i have no real way, other than what the system feels to me, to test this issue.

[Gonçalo Marrafa (goncalo-marrafa)]

OK, so for a more scientific test. I used sysbench to test CPU performance. I tested with the stock 3.11.0-15-generic kernel and the test 3.13.0-031300rc3-generic kernel, both before and resume a suspend/resume cycle.

The command i used to perform the tests:
sysbench --num-threads=8 --test=cpu --cpu-max-prime=50000 run

The results:

3.11.0-15-generic: 12.4127s
3.11.0-15-generic (after suspend): 78.8023s

3.13.0-031300rc3-generic: 12.2202s
3.13.0-031300rc3-generic (after suspend): 35.0208s

We can very similar performance before suspend and degradation after resume. A huge degradation with 3.11 (about 6.5x slower) and a smaller one (about 3x slower) with 3.13.

Hope these help.

[Gonçalo Marrafa (goncalo-marrafa)]

I can't tell. The computer is new and the only distro i've installed on it is Saucy.

[penalvch (penalvch)]

Gonçalo Marrafa, for regression testing purposes could you please test for this in Precise via http://releases.ubuntu.com/precise/ and advise to the results?

[Gonçalo Marrafa (goncalo-marrafa)]

I'm sorry, i can't. This is my work machine and i can't afford constantly changing OS. I can't help with that. Hope someone else who has the same issue can do it.

[BarthV (barthv)]

@penalvch :

I got the same profesionnal DELL laptop and the same issue with Precise.
On AC or battery, cur_freq is sticked to 800000. I tried to remove cpufreq tools, but nothing changed.

The strange part is when I plug my laptop on my Dell dock at the office, power strategies are working absolutely well ... As soon as it runs undocked, cpu is working at its lowest speed step even when i've not suspended the system once.

[penalvch (penalvch)]

FRnunurs, thank you for your comment. So your hardware and problem may be tracked, could you please file a new report with Ubuntu by executing the following in a terminal while booted into a Ubuntu repository kernel (not a mainline one) via:
ubuntu-bug linux

For more on this, please read the official Ubuntu documentation:
Ubuntu Bug Control and Ubuntu Bug Squad: https://wiki.ubuntu.com/Bugs/BestPractices#X.2BAC8-Reporting.Focus_on_One_Issue
Ubuntu Kernel Team: https://wiki.ubuntu.com/KernelTeam/KernelTeamBugPolicies#Filing_Kernel_Bug_reports
Ubuntu Community: https://help.ubuntu.com/community/ReportingBugs#Bug_reporting_etiquette

When opening up the new report, please feel free to subscribe me to it.

Thank you for your understanding.

Helpful bug reporting tips:
https://wiki.ubuntu.com/ReportingBugs

[Gonçalo Marrafa (goncalo-marrafa)]

Guys, any news regarding this matter? Are there any developments regarding this issue? Is there something else we can do to help identify the problem?

[penalvch (penalvch)]

Gonçalo Marrafa, this would be pending the results of https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1260112/comments/23 (live environment would be fine).

[Launchpad Janitor (janitor)]

[Expired for linux (Ubuntu) because there has been no activity for 60 days.]

[domink (domingo-berron)]

The same issue occurs when the laptop is installed with Windows 7.

I think that it is not related with SO but with some BIOS "feature".

This laptop requires its own AC unit with 130W. If you use a lower power supply (but DELL also), the CPU performanc goes bellow 800Mgh.

But... I suspect a bug on this routine becasue time to time, after resuming the laptop... I have found that the CPU speed is not recovered.

To solve it, I unplug the power supply and plug again.

[penalvch (penalvch)]

domink, thank you for your comment. So your hardware and problem may be tracked, could you please file a new report with Ubuntu by executing the following in a terminal while booted into a Ubuntu repository kernel (not a mainline one) via:
ubuntu-bug linux

For more on this, please read the official Ubuntu documentation:
Ubuntu Bug Control and Ubuntu Bug Squad: https://wiki.ubuntu.com/Bugs/BestPractices#X.2BAC8-Reporting.Focus_on_One_Issue
Ubuntu Kernel Team: https://wiki.ubuntu.com/KernelTeam/KernelTeamBugPolicies#Filing_Kernel_Bug_reports
Ubuntu Community: https://help.ubuntu.com/community/ReportingBugs#Bug_reporting_etiquette

When opening up the new report, please feel free to subscribe me to it.

Thank you for your understanding.

Helpful bug reporting tips:
https://wiki.ubuntu.com/ReportingBugs

[Olivier Berger (oberger)]

http://www.williambharding.com/blog/technology/fixed-my-i7-intel-dell-laptop-is-ridiculously-slow/ seems to suggest a workaround : unsetting the speedstep option in the BIOS.

It seems to be working on mine with a Debian wheezy install.

[Olivier Berger (oberger)]

Attention regarding previosu comment #32 : I've experienced a strange and dangerous looking power down when using a 65W adapter after I disabled the speedstep BIOS option, while the machine was on heavy duty (ripping video)... so change the BIOS setting at your own risk !

[Philippe Ombredanne (pombredanne)]

See http://www.dell.com/support/home/us/en/04/Drivers/DriversDetails?driverId=K04R3&fileId=3450461628&osCode=W764&productCode=latitude-e6540-laptop&languageCode=EN&categoryId=BI
The latest BIOS A14 from April 2015 has this single note:
"- Fixed CPU may be limited at low speed after resume from standby"

[penalvch (penalvch)]

Philippe Ombredanne, please see https://help.ubuntu.com/community/BIOSUpdate#FAQ .