Hi, I updated this bug a couple of months ago to see if recent backport
fixes addressed the issue. If this has helped, please add your notes to
the bug report so we can close the issue.
** Changed in: thermald (Ubuntu)
Assignee: Colin Ian King (colin-king) => Ubuntu Kernel Team
(ubuntu-kernel-team)
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https://bugs.launchpad.net/bugs/1763144
Title:
Significantly lower power and thermal limits on ThinkPad T480s (and
probably others) than on Windows
Status in linux package in Ubuntu:
Invalid
Status in thermald package in Ubuntu:
Incomplete
Bug description:
A ThinkPad T480s under windows has a power limit of 44W, both short
and long term, with a thermal maximum of about 93C or so. Under Linux,
the power limits are 44W and 15W (short) or so, and the thermal limit
is 80C, causing a significant performance loss.
Looking at MSR and MCHBAR values, we can see that the values are
correctly at 44W in the MSR, but the MCHBAR is set to a lower value:
$ sudo rdmsr -a 0x610
42816000dd8160
42816000dd8160
42816000dd8160
42816000dd8160
42816000dd8160
42816000dd8160
42816000dd8160
42816000dd8160
$ sudo /home/jak/Downloads/iotools-1.5/iotools mmio_read64 0xfed159a0
0x0042816000dd8078
Setting the MCHBAR to the same value as the MSR register solves the problem.
At some point intel-rapl seems to reduce overall frequency to 600 MHz, though.
The thermal limit is configured in MSR register 0x1a2; rdmsr -f 29:24
-d 0x1a2 returns 20. Setting those bits to 7 increases it, resulting
in performance comparative to Windows.
Most of the analysis is based on the analysis in
https://www.reddit.com/r/thinkpad/comments/870u0a/t480s_linux_throttling_bug/
This applies to all bionic kernels I have tested so far, including
Ubuntu 4.15.0-13.14-generic 4.15.10
---
ApportVersion: 2.20.9-0ubuntu4
Architecture: amd64
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/pcmC2D0p: jak 5881 F...m pulseaudio
/dev/snd/controlC2: jak 5881 F.... pulseaudio
/dev/snd/controlC1: jak 5881 F.... pulseaudio
/dev/snd/controlC0: jak 5881 F.... pulseaudio
CurrentDesktop: GNOME
DistroRelease: Ubuntu 18.04
InstallationDate: Installed on 2018-03-14 (28 days ago)
InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Alpha amd64 (20180313)
MachineType: LENOVO 20L8S02D00
Package: linux (not installed)
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: root=/dev/mapper/ubuntu--vg-root ro rootflags=subvol=@
quiet splash vt.handoff=1
ProcVersionSignature: Ubuntu 4.15.0-13.14-generic 4.15.10
RelatedPackageVersions:
linux-restricted-modules-4.15.0-13-generic N/A
linux-backports-modules-4.15.0-13-generic N/A
linux-firmware 1.173
Tags: bionic
Uname: Linux 4.15.0-13-generic x86_64
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip kvm lpadmin lxd plugdev sambashare sudo
_MarkForUpload: True
dmi.bios.date: 01/22/2018
dmi.bios.vendor: LENOVO
dmi.bios.version: N22ET31W (1.08 )
dmi.board.asset.tag: Not Available
dmi.board.name: 20L8S02D00
dmi.board.vendor: LENOVO
dmi.board.version: Not Defined
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: None
dmi.modalias:
dmi:bvnLENOVO:bvrN22ET31W(1.08):bd01/22/2018:svnLENOVO:pn20L8S02D00:pvrThinkPadT480s:rvnLENOVO:rn20L8S02D00:rvrNotDefined:cvnLENOVO:ct10:cvrNone:
dmi.product.family: ThinkPad T480s
dmi.product.name: 20L8S02D00
dmi.product.version: ThinkPad T480s
dmi.sys.vendor: LENOVO
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