The described behavior with CPU thermal throtteling was confirmed by Lenovo. The limits are higher as in Windows "DPTF" works by driver support and enables the "desk mode". In Linux the "desk mode" is never reached due to the lack of sensor information and the system operates in the "lap mode" which has much lower trip temp.
See forum threat there: https://forums.lenovo.com/t5/Other-Linux-Discussions/X1C6-T480s-low- cTDP-and-trip-temperature-in-Linux/td-p/4028489 The patches are not published yet for all platforms. But as T480s, many other models e.g. X1C6 are affected too. Background info by Lenovo: https://forums.lenovo.com/lnv/attachments/lnv/Special_Interest_Linux/13642/1/Linux%20Thermal%20throttling.pdf Technical description by German magazine in German language only: https://www.notebookcheck.com/Lenovo-ThinkPads-haben-mit-CPU-Throttling- unter-Linux-zu-kaempfen-Loesung-in- Arbeit.435573.0.html?fbclid=IwAR0koYya67WfT8SlZmDuNx6F51niWYHzvd4C1MMzZdiyCJLutmC_4p3BJVs -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. 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 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 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1763144/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
