Fan control stops working on resume for Dell Precision
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
linux-signed (Ubuntu) |
New
|
Undecided
|
Unassigned | ||
linux-signed-hwe (Ubuntu) |
New
|
Undecided
|
Unassigned |
Bug Description
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_
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-
ProcVersionSign
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)
This still happens on a fresh Focal install using linux-image- 5.4.0-26- generic version 5.4.0-26.30