Public bug reported:
First off: I'm running Ubuntu 14.04.2 LTS "Trusty Tahr", yet ubuntu-bug
linux started the bug report against linux-lts-utopic. I hope it knows
what it's doing : )
uname -a says "Linux aspire5315 3.16.0-41-generic #57~14.04.1-Ubuntu SMP
Thu Jun 18 18:01:13 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux".
Now to the problem.
The fan on this particular Laptop seems to be either controlled by BIOS or -
after the operating system signals somehow(tm) that it's capable of doing so -
completely by software. There is (I assume it's implemented in the mainboard
firmware) an emergency-power-off once the temperature exceeds a certain
threshold, that's what causing the sudden poweroff after a while.
Without any modifications, if you power it up (assuming its already warm
from a previous session), the fan works correctly. If you load BIOS or
GRUB, no problems. I could confirm temperature-dependent control works
by loading a memtest86 and letting it run for a few hours; Fan speed
kept going up and down, machine did not crash.
Once you load a linux kernel (LiveCD exhibits the same behaviour), the
fan stops completely and the system starts heating up. I was able to get
through a complete ubuntu installation before poweroff by not using an
internet connection and clicking defaults as fast as possible, starting
with the machine cold.
After I had ubuntu installed, thanks to much help at bug report #728733
I have made the following discoveries.
(1) Booting linux with "acpi=off" results in a kernel panic (I had to replace
"quiet splash" with "verbose" to see that), but the fan stays on.
(2) Booting linux with "acpi=off noapic" or "acpi=off nolapic" results in the
fan working correctly, but the wifi card doen't work.
(3) Booting linux normally, if you monitor
/sys/class/thermal/thermal_zone0/temp it stays at 40000 (40°C) even if
lm-sensors' coretemp tells me that the processor is quite beyond that. [note:
It is possible that the fan is just so quiet at the 40°C setting that I'm
thinking its off]. Thermald also seems to depend on this temperature reading
and therefore does not throttle the CPU.
(4) Sending the machine to standby and waking it up again results in the
thermal_zone0/temp getting updated regularly (it seems to follow coretemp with
a few seconds lag) and the fan turning faster and slower. In this state, the
system is perfectly usable.
What I would like is to have the system in state 4 (fan turning and
adjusting to temperature) without requiring human intervention, either
by avoiding the fan stopping in the first place (preferred) or by re-
starting it automated sometime in the boot process.
> We also need:
1) The release of Ubuntu you are using
'lsb_release -rd' gives
Description: Ubuntu 14.04.2 LTS
Release: 14.04
2) The version of the package you are using
'apt-cache policy linux-image-$(uname -r)' says I'm running
3.16.0-41.57~14.04.1
3) What you expected to happen
System fan stays on after grub->linux handoff (or only stays off for a brief
time period and comes back up automatically)
4) What happened instead
System fan stays off until I suspend and wakeup the machine, possibly resulting
in heat emergency poweroff if I am too slow or forget to do it
ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: linux-image-3.16.0-41-generic 3.16.0-41.57~14.04.1
ProcVersionSignature: Ubuntu 3.16.0-41.57~14.04.1-generic 3.16.7-ckt11
Uname: Linux 3.16.0-41-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.11
Architecture: amd64
CurrentDesktop: Unity
Date: Sun Jul 5 12:16:55 2015
InstallationDate: Installed on 2001-01-02 (5296 days ago)
InstallationMedia: Ubuntu 14.04.2 LTS "Trusty Tahr" - Release amd64+mac
(20150218.1)
SourcePackage: linux-lts-utopic
UpgradeStatus: No upgrade log present (probably fresh install)
** Affects: linux-lts-utopic (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug trusty
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https://bugs.launchpad.net/bugs/1471530
Title:
Acer Aspire 5315: Fan turns off when loading linux, resulting in
system overheat and emergency shutdown
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