To check the theory about the Ubuntu-specific patches, I tried to boot another Linux distro (Fedora Live 35) in order to see if the problem would exist: it did not.
The kernel used was: 5.14.10-300.fc35.x86_64. Which is more recent that the kernel 5.13.0-20, currently used by Ubuntu 21.10. Therefore, it looks that both the older Ubuntu-specific kernel and the newest Fedora kernel do _not_ have the problem, thanks to some custom patches that (apparently) do _not_ exist in 5.13.0-19 nor in the mainstream Linux kernel. It's getting even more tricky. An alternative long-shot theory is that thermal management policies changed in the newest Ubuntu, but does not activate with kernel 5.11 because of the lack of some kernel feature. That would explain why the problem exists with the mainstream kernel as well, but not on another distro. -- 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/1947614 Title: Laptop fans spin at ~50% w/o CPU load with kernel 5.13 Status in linux package in Ubuntu: Confirmed Bug description: After upgrading from Ubuntu 21.04 to Ubuntu 21.10 a few days ago, I noticed that the fans of my laptop (Lenovo ideapad 700-15ISK) were spinning all the time at about ~50%, no matter the CPU load. I forced all my cores to run at 100% with a simple while(1) loop to see if the fan speed would increase but nothing. Apparently, no matter the CPU load and temperature, with kernel 5.13.0-19 the fans of my laptop spin at the same RPM. From their noise, I believe that's about 50%. Therefore, I decided to boot the same Ubuntu 21.10 with the older kernel 5.11.0-37 and the problem disappeared. Looks like in the newer kernel there is a problem with the control of fans for my HW. To complete the picture, I built and booted kernel v5.15-rc5 to see if with a bleeding edge kernel the problem would disappear: it didn't. Therefore, the problem appears to be introduced somewhere between kernel 5.11 and kernel 5.13. The output of `sensors`, unfortunately doesn't show any fans and that's the same no matter the kernel version: pch_skylake-virtual-0 Adapter: Virtual device temp1: +54.5°C BAT0-acpi-0 Adapter: ACPI interface in0: 12.25 V coretemp-isa-0000 Adapter: ISA adapter Package id 0: +39.0°C (high = +100.0°C, crit = +100.0°C) Core 0: +37.0°C (high = +100.0°C, crit = +100.0°C) Core 1: +38.0°C (high = +100.0°C, crit = +100.0°C) Core 2: +39.0°C (high = +100.0°C, crit = +100.0°C) Core 3: +38.0°C (high = +100.0°C, crit = +100.0°C) acpitz-acpi-0 Adapter: ACPI interface temp1: +39.0°C (crit = +99.0°C) temp2: +42.0°C (crit = +85.0°C) ProblemType: Bug DistroRelease: Ubuntu 21.10 Package: linux-image-5.13.0-19-generic 5.13.0-19.19 ProcVersionSignature: Ubuntu 5.13.0-19.19-generic 5.13.14 Uname: Linux 5.13.0-19-generic x86_64 NonfreeKernelModules: nvidia_modeset nvidia ApportVersion: 2.20.11-0ubuntu70 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC1: vlad 5972 F.... pulseaudio /dev/snd/controlC0: vlad 5972 F.... pulseaudio CasperMD5CheckResult: unknown CurrentDesktop: ubuntu:GNOME Date: Mon Oct 18 19:04:03 2021 InstallationDate: Installed on 2020-03-17 (579 days ago) InstallationMedia: Ubuntu 19.10 "Eoan Ermine" - Release amd64 (20191017) MachineType: LENOVO 80RU ProcFB: 0 i915drmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.13.0-19-generic root=UUID=0e855d19-79da-402d-9586-b7bfe9a9622a ro RelatedPackageVersions: linux-restricted-modules-5.13.0-19-generic N/A linux-backports-modules-5.13.0-19-generic N/A linux-firmware 1.201 SourcePackage: linux UpgradeStatus: Upgraded to impish on 2021-10-16 (1 days ago) dmi.bios.date: 08/09/2017 dmi.bios.release: 1.61 dmi.bios.vendor: LENOVO dmi.bios.version: E5CN61WW dmi.board.asset.tag: No Asset Tag dmi.board.name: Lenovo ideapad 700-15ISK dmi.board.vendor: LENOVO dmi.board.version: NO DPK dmi.chassis.asset.tag: No Asset Tag dmi.chassis.type: 10 dmi.chassis.vendor: LENOVO dmi.chassis.version: Lenovo ideapad 700-15ISK dmi.ec.firmware.release: 1.22 dmi.modalias: dmi:bvnLENOVO:bvrE5CN61WW:bd08/09/2017:br1.61:efr1.22:svnLENOVO:pn80RU:pvrLenovoideapad700-15ISK:skuLENOVO_MT_80RU_BU_idea_FM_Lenovoideapad700-15ISK:rvnLENOVO:rnLenovoideapad700-15ISK:rvrNODPK:cvnLENOVO:ct10:cvrLenovoideapad700-15ISK: dmi.product.family: IDEAPAD dmi.product.name: 80RU dmi.product.sku: LENOVO_MT_80RU_BU_idea_FM_Lenovo ideapad 700-15ISK dmi.product.version: Lenovo ideapad 700-15ISK dmi.sys.vendor: LENOVO To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1947614/+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
