CPU0 (and sometimes other cores too) is not entering C10 half of the time when system is idle. "top" shows a touchpad driver takes 5%~6% of CPU usage, and "/proc/interrupts" reveals considerable interrupts from the touchpad device. This results in additional 4~5 watt power consumption.
This anomaly can be workarounded by simply touching the touchpad - in other words, it is more visible when using a USB mouse.
This can be fixed by a kernel 5.5 commit 52cf93e63ee6 which is included in bionic (4.15) and focal kernel (5.4) but not in eoan (5.3).
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ProblemType: Bug
ApportVersion: 2.20.9-0ubuntu7.11
Architecture: amd64
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/controlC0: alexhung 3397 F.... pulseaudio
/dev/snd/pcmC0D0p: alexhung 3397 F...m pulseaudio
CurrentDesktop: ubuntu:GNOME
DistroRelease: Ubuntu 18.04
InstallationDate: Installed on 2019-10-29 (118 days ago)
InstallationMedia: Ubuntu 18.04.3 LTS "Bionic Beaver" - Release amd64 (20190805)
MachineType: Dell Inc. Precision 3530
Package: linux (not installed)
ProcFB: 0 i915drmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.3.0-40-generic root=UUID=b0c947ea-9aa0-4ca2-a634-7b925900c129 ro quiet splash vt.handoff=1
ProcVersionSignature: Ubuntu 5.3.0-40.32~18.04.1-generic 5.3.18
RelatedPackageVersions:
linux-restricted-modules-5.3.0-40-generic N/A
linux-backports-modules-5.3.0-40-generic N/A
linux-firmware 1.173.14
Tags: bionic
Uname: Linux 5.3.0-40-generic x86_64
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip docker lpadmin plugdev sambashare sudo
_MarkForUpload: True
dmi.bios.date: 01/30/2018
dmi.bios.vendor: Dell Inc.
dmi.bios.version: 99.6.4
dmi.board.vendor: Dell Inc.
dmi.chassis.type: 10
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.:bvr99.6.4:bd01/30/2018:svnDellInc.:pnPrecision3530:pvr:rvnDellInc.:rn:rvr:cvnDellInc.:ct10:cvr:
dmi.product.family: Precision
dmi.product.name: Precision 3530
dmi.product.sku: 0820
dmi.sys.vendor: Dell Inc.
This bug is missing log files that will aid in diagnosing the problem. While running an Ubuntu kernel (not a mainline or third-party kernel) please enter the following command in a terminal window:
apport-collect 1864527
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.