Public bug reported: Previously reported here as a kernel bug ( https://bugs.launchpad.net/ubuntu/+source/linux-signed- hwe-5.8/+bug/1910562 ), now after finding root cause reporting here also.
After updating via apt dist-upgrade from kernel 5.4.0-59 to kernel 5.8.0-34 the fan on my machine started switching on (for an instant) and off every 10 seconds even when idle with CPU at 48/50°C. Switching back to previous kernel solves temporary the problem, i.e. fans are always off with light desktop work. The new behavior is really annoying and I guess not healthy for the fans. I'm on latest Dell bios, with every other package updated. So, after testing several different kernels and live distros to pinpoint this bug, I finally found out the problem: it's an interaction between lm-sensors and amdgpu driver with kernel > 5.4.0. I found out by chance because I noticed the problem happened only after logging in with a graphical session. This is what is happening: - a gnome extension to monitor sensors/temps calls the 'sensors' utility from package lm-sensors every 10 senconds - sensors 'hangs' for a couple of seconds when poking something related to the amdgpu driver - amdgpu driver spits some warning/errors on vt console and dmesg - fans starts spinning for one sec - then sensors continue normally displaying the readouts from other sensor This is the output of 'sensors', taken in a non-graphical console (ctr+alt+F3) with kernel 5.8.0-41: [UNRELATED OUTPUT] amdgpu-pci-0100 Adapter: PCI adapter [ 112.780951] [drm:dce110_edp_wait_for_hpd_ready [amdgpu]] *ERROR* dce110_edp_wait_for_hpd_ready: wait timed out! [ 113.380939] [drm:dce110_edp_wait_for_hpd_ready [amdgpu]] *ERROR* dce110_edp_wait_for_hpd_ready: wait timed out! vddgfx: 1.05 V edge: +44.0°C (crit = +94.0°C, hyst = -273.1°C) power1: 7.12 W (cap = 35.00 W) [UNRELATED OUTPUT] This is the complete kernel log from amgpu when this happens: [ 111.572873] [drm] PCIE GART of 256M enabled (table at 0x000000F400000000). [ 112.780951] [drm:dce110_edp_wait_for_hpd_ready [amdgpu]] *ERROR* dce110_edp_wait_for_hpd_ready: wait timed out! [ 113.380939] [drm:dce110_edp_wait_for_hpd_ready [amdgpu]] *ERROR* dce110_edp_wait_for_hpd_ready: wait timed out! [ 113.411556] [drm] UVD and UVD ENC initialized successfully. [ 113.521534] [drm] VCE initialized successfully. It seems that lm-sensors poking the amdgpu thermal sensor i triggering some sort of reset and/or causing the thermal infrastructure to spin up the fans Note that this is not happening with kernel 5.4, with which sensor reports this: amdgpu-pci-0100 Adapter: PCI adapter vddgfx: N/A edge: N/A (crit = +94.0°C, hyst = -273.1°C) power1: N/A (cap = 35.00 W) [UNRELATED OUTPUT] Note the missing data about amdgpu and no console kernel warning messages. Disabling the gnome sensor check extension solves the problem for now, but there is definitely something going on here. Please feel free to ask me for anything I can do/test to help solve this problem ProblemType: Bug DistroRelease: Ubuntu 20.04 Package: xserver-xorg-video-amdgpu 19.1.0-1 ProcVersionSignature: Ubuntu 5.8.0-41.46~20.04.1-generic 5.8.18 Uname: Linux 5.8.0-41-generic x86_64 ApportVersion: 2.20.11-0ubuntu27.16 Architecture: amd64 BootLog: Error: [Errno 13] Permission denied: '/var/log/boot.log' CasperMD5CheckResult: skip CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins' CompositorRunning: None CurrentDesktop: ubuntu:GNOME Date: Wed Feb 3 14:16:26 2021 DistUpgraded: Fresh install DistroCodename: focal DistroVariant: ubuntu GraphicsCard: Intel Corporation UHD Graphics 630 (Mobile) [8086:3e9b] (prog-if 00 [VGA controller]) Subsystem: Dell UHD Graphics 630 (Mobile) [1028:0926] Advanced Micro Devices, Inc. [AMD/ATI] Lexa XT [Radeon PRO WX 3200] [1002:6981] (prog-if 00 [VGA controller]) Subsystem: Dell Lexa XT [Radeon PRO WX 3200] [1028:0926] InstallationDate: Installed on 2020-05-06 (273 days ago) InstallationMedia: Ubuntu 20.04 LTS "Focal Fossa" - Release amd64 (20200423) MachineType: Dell Inc. Precision 7540 ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.8.0-41-generic root=UUID=c39f518b-f5c9-47c5-8e7f-42d970d2dedb ro quiet splash vt.handoff=7 SourcePackage: xserver-xorg-video-amdgpu UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 01/08/2021 dmi.bios.release: 1.11 dmi.bios.vendor: Dell Inc. dmi.bios.version: 1.11.2 dmi.board.name: 0XMC3F dmi.board.vendor: Dell Inc. dmi.board.version: A00 dmi.chassis.type: 10 dmi.chassis.vendor: Dell Inc. dmi.modalias: dmi:bvnDellInc.:bvr1.11.2:bd01/08/2021:br1.11:svnDellInc.:pnPrecision7540:pvr:rvnDellInc.:rn0XMC3F:rvrA00:cvnDellInc.:ct10:cvr: dmi.product.family: Precision dmi.product.name: Precision 7540 dmi.product.sku: 0926 dmi.sys.vendor: Dell Inc. version.compiz: compiz N/A version.libdrm2: libdrm2 2.4.102-1ubuntu1kisak1~f version.libgl1-mesa-dri: libgl1-mesa-dri 20.3.4~kisak1~f version.libgl1-mesa-glx: libgl1-mesa-glx N/A version.xserver-xorg-core: xserver-xorg-core 2:1.20.9-2ubuntu1.2~20.04.1 version.xserver-xorg-input-evdev: xserver-xorg-input-evdev N/A version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:19.1.0-1 version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20200226-1 version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.16-1 ** Affects: xserver-xorg-video-amdgpu (Ubuntu) Importance: Undecided Status: New ** Tags: amd64 apport-bug focal lm-sensors thermal third-party-packages ubuntu -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1914413 Title: amdgpu driver interaciton with lm-sensor causes fans to spin up in kernel 5.8 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-amdgpu/+bug/1914413/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs