Extreme regression in battery autonomy with kernel 4.15

[Jacob Zimmermann]

Since upgrading to kernel 4.15, my laptop (HP Elitebook 850 G3) lasts less than one hour on a fully charged battery. On Ubuntu 17.10 with kernel 4.13, the autonomy was typically in excess of 5 hours.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: linux-image-lowlatency 4.15.0.20.23
ProcVersionSignature: Ubuntu 4.15.0-20.21-lowlatency 4.15.17
Uname: Linux 4.15.0-20-lowlatency x86_64
ApportVersion: 2.20.9-0ubuntu7
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: jzimm 3538 F.... pulseaudio
CurrentDesktop: ubuntu:GNOME
Date: Fri Apr 27 20:10:02 2018
InstallationDate: Installed on 2018-04-03 (24 days ago)
InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Alpha amd64 (20180402)
MachineType: HP HP EliteBook 850 G3
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/bionic/vmlinuz-4.15.0-20-lowlatency root=UUID=b6480aee-7c63-4ce4-9e8d-cdbef768b982 ro rootflags=subvol=@,relatime,autodefrag,space_cache quiet splash module.sig_enforce=1 intel_pstate=skylake_hwp radeon.si_support=0 radeon.cik_support=0 amdgpu.si_support=1 amdgpu.cik_support=1 vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-4.15.0-20-lowlatency N/A
 linux-backports-modules-4.15.0-20-lowlatency N/A
 linux-firmware 1.173
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 07/31/2016
dmi.bios.vendor: HP
dmi.bios.version: N75 Ver. 01.10
dmi.board.name: 8079
dmi.board.vendor: HP
dmi.board.version: KBC Version 85.6F
dmi.chassis.asset.tag: 5CG6351LQL
dmi.chassis.type: 10
dmi.chassis.vendor: HP
dmi.modalias: dmi:bvnHP:bvrN75Ver.01.10:bd07/31/2016:svnHP:pnHPEliteBook850G3:pvr:rvnHP:rn8079:rvrKBCVersion85.6F:cvnHP:ct10:cvr:
dmi.product.family: 103C_5336AN G=N L=BUS B=HP S=ELI
dmi.product.name: HP EliteBook 850 G3
dmi.sys.vendor: HP

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This change was made by a bot.

[Joseph Salisbury (jsalisbury)]

Does this bug go away if you boot back into the prior kernel version?

Would it be possible for you to test the latest upstream kernel? Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v4.16 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/v4.17-rc3

[Jacob Zimmermann (jacob)]

I have been trying various kernels to see if it would help. The battery consumption got (almost) back to normal under 4.17.0~rc3 but now with rc6 is down to 1:30h again.

[Ads20000 (ads20000)]

As per jacob's comment have added the tag and changed to Confirmed, Joseph do you know how this bug should be progressed? Where it should be forwarded upstream or what further debug work could be done? A test against a yet newer kernel probably wouldn't go amiss but not sure not doing that should put the bug back to Incomplete since then we may always be behind.

[Kai-Heng Feng (kaihengfeng)]

Please find the first -rc kernel in [1] that introduces the issue:

[1] http://kernel.ubuntu.com/~kernel-ppa/mainline