Public bug reported:
This system is a Dell Precision Tower 3420 with the latest BIOS 2.13.1,
kernel version is 5.3.0-26-generic (HWE, bionic)
Freshly booting the system and doing something CPU intensive, like
compiling a kernel, cause the CPU fan to ramp up as expected and the CPU
temperatures remain acceptable.
After suspending (ie Alt-clicking the power button in Unity) and then
resuming, the CPU fan runs at a permanent low frequency and does not
ramp up. Doing something like a kernel build causes the CPU to overheat
and logs messages to dmesg.
Investigating I see that the dell_smm_hwmon driver has a 'temp2' input
that reflects the CPU temperature. Upon power up the value works
properly, after resume it returns -ENODATA. The other sensor for CPU
temperature (thermal_zone3/temp, x86_pkg_temp) still works correctly.
Blacklisting the dell_smm_hwmon driver has no impact
Dell Precisions are listed as compatible with Ubuntu, and this system
was purchased with Ubuntu pre-installed from Dell, so it is surpsing
something so basic isn't working?
ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: linux-image-5.3.0-26-generic 5.3.0-26.28~18.04.1
ProcVersionSignature: Ubuntu 5.3.0-26.28~18.04.1-generic 5.3.13
Uname: Linux 5.3.0-26-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.9
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Mon Jan 27 15:48:39 2020
InstallationDate: Installed on 2018-08-04 (540 days ago)
InstallationMedia: Ubuntu 18.04.1 LTS "Bionic Beaver" - Release amd64 (20180725)
SourcePackage: linux-signed-hwe
UpgradeStatus: No upgrade log present (probably fresh install)
** Affects: linux-signed-hwe (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug bionic
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https://bugs.launchpad.net/bugs/1861028
Title:
Fan control stops working on resume for Dell Precision
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