System doesn't enter low power states on Skylake processors (Lenovo Thinkpad X260)

[Konstantin]

Powertop shows, that the system does not enter the low power idle states of the CPU (beyond PC2) despite the individual cores all reaching their lowest power idle states (C10). See attached screen shot for a typical example of powertop's output.

A result of this is a vastly reduced battery live.

Furthermore, Intel suggests that not enabling low power idle states may have a negative impact on the life time of the CPU. See
https://mjg59.dreamwidth.org/41713.html

The laptop is a Lenovo ThinkPad x260 which is is a Ubuntu certified system (http://www.ubuntu.com/certification/hardware/201511-20298/).

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: linux-image-4.4.0-21-generic 4.4.0-21.37 [modified: boot/vmlinuz-4.4.0-21-generic]
ProcVersionSignature: Ubuntu 4.4.0-21.37-generic 4.4.6
Uname: Linux 4.4.0-21-generic x86_64
ApportVersion: 2.20.1-0ubuntu2
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: kaymes 1572 F.... pulseaudio
CurrentDesktop: Unity
Date: Fri May 6 07:53:35 2016
HibernationDevice: RESUME=UUID=7b2bf86b-4ad7-48d5-ba12-ed741ffcefea
InstallationDate: Installed on 2016-05-04 (1 days ago)
InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1)
Lsusb:
 Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
 Bus 001 Device 003: ID 5986:0706 Acer, Inc
 Bus 001 Device 002: ID 8087:0a2b Intel Corp.
 Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
MachineType: LENOVO 20F6CTO1WW
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-4.4.0-21-generic.efi.signed root=/dev/mapper/ubuntu--vg-root ro quiet splash vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-4.4.0-21-generic N/A
 linux-backports-modules-4.4.0-21-generic N/A
 linux-firmware 1.157
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 01/25/2016
dmi.bios.vendor: LENOVO
dmi.bios.version: R02ET44W (1.17 )
dmi.board.asset.tag: Not Available
dmi.board.name: 20F6CTO1WW
dmi.board.vendor: LENOVO
dmi.board.version: SDK0J40709 WIN
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: None
dmi.modalias: dmi:bvnLENOVO:bvrR02ET44W(1.17):bd01/25/2016:svnLENOVO:pn20F6CTO1WW:pvrThinkPadX260:rvnLENOVO:rn20F6CTO1WW:rvrSDK0J40709WIN:cvnLENOVO:ct10:cvrNone:
dmi.product.name: 20F6CTO1WW
dmi.product.version: ThinkPad X260
dmi.sys.vendor: LENOVO

[Brad Figg (brad-figg)]

This change was made by a bot.

[Joseph Salisbury (jsalisbury)]

Would it be possible for you to test the latest upstream kernel? Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v4.6 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'.

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/v4.6-rc6-wily/

[Konstantin (list-kseiler)]

I tried the upstream kernel you linked to, but the problem is still the same.

http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.6-rc6-wily/

$ uname -a
Linux kaymes 4.6.0-040600rc6-generic #201605012031 SMP Mon May 2 00:33:26 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux

Btw, the kernel you linked to was for wily whereas this system is already xenial.

[penalvch (penalvch)]

Konstantin, to see if this is resolved, could you please test the latest Intel upstream via http://kernel.ubuntu.com/~kernel-ppa/mainline/drm-intel-nightly/ and advise to the results?

[Konstantin (list-kseiler)]

I just tried the latest of the intel drm kernels. Still the same: the cores all reach C10 whereas the package only reaches C2 (pc2).

$ uname -a
Linux kaymes 4.7.0-994-generic #201606052244 SMP Mon Jun 6 02:46:22 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux

[Konstantin (list-kseiler)]

I also performed a BIOS update. Still the same: the cores all reach C10 whereas the package only reaches C2 (pc2).

$ uname -a
Linux kaymes 4.7.0-994-generic #201606052244 SMP Mon Jun 6 02:46:22 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux

$ sudo dmidecode -s bios-version
R02ET46W (1.19 )

[penalvch (penalvch)]

Konstantin, the issue you are reporting is an upstream one. Could you please report this problem following the instructions verbatim at https://wiki.ubuntu.com/Bugs/Upstream/kernel to the appropriate mailing list (TO Daniel Vetter and Jani Nikula CC intel-gfx)?

Please provide a direct URL to your post to the mailing list when it becomes available so that it may be tracked.

Thank you for your understanding.