Acer 5920, Mint 12, CPU fan nearly full crank

[Telkwa]

Good day!
Running an Acer 5920 laptop. Fan is howling. It's been running Ubuntu 10.04 for the last year or two. With 10.04 the fan was almost inaudible most of the time. In the last week I've tried Ubuntu 11.10, Xubuntu 11.10, Mint 11, and now Mint 12 w/ Cinnamon. Fan ramped up under all of these OS'es, but after installing Cinnamon it appears to have ramped up a little more. Doesn't make any sense that Cinnamon would change fan speed, does it?

I tried setting up pwmconfig, but there are no pwm-capable devices.
lm-sensors picks up just one module, "coretemp".
I installed xsensors, which says CPU temp is 40.0 deg. C
gkrellm sez CPU usage is low. Barely bounces off 0% at an idle.
I disassembled the lappy last week to replace the CMOS battery, which is cleverly situated in the deepest depths. Cleaned out the CPU fan/heat tube/exhaust grill (not much dust) and applied a dab of Arctic Silver thermal paste in place of the original heat pad.

Does anyone have any ideas? I've got the laptop setting here next to me idling. Fan speed hasn't changed one bit in an hour.

EDIT: I pulled the HDD running Mint 12, replacing it with the OEM HDD. The OEM HDD still has Ubuntu 8.04 on it. The fan fell to "almost inaudible" as soon as 8.04 booted up. So to this amateur it sure looks like something in the newer kernels that's not controlling the laptop fan as well as older kernels did.

[xenopeek]

When you say you used lm-sensors, have you run sensors-detect as well? As in, from terminal run;

Code: Select all

sudo sensors-detect
# follow instructions at the end
# after reboot run sensors to get temperature

It is a known problem that the Linux kernel from 2.6.38 release on up has a problem with power management (not being conservative). Meaning, the CPU isn't actually going into idle if you have it just sitting there. As such, the fans have to remain running. Will be fixed in kernel 3.3 (http://www.phoronix.com/scan.php?page=news_item&px=MTAyMjk).

[Telkwa]

Thanks for replying!
Yes, I'm sorry, I didn't explain very thoroughly. I went thru the sensors-detect routine. lm-sensors only found the one module, called coretemp.

Funny you mention the Phoronix discovery - I stumbled onto that a few days ago and wondered if there was a connection. But gkrellm shows the CPU cores bumping along at almost 0% when I'm not doing anything so I didn't think that was related.

You're going to think this is weird (it sounds weird to me even saying it) but after I swapped the OEM HDD out and plugged in the HDD with Mint 12 installed, the CPU fan didn't seem to be cranking as hard as it was. It still seems a bit louder than with the OEM HDD but not 'driving-me-crazy' loud.

Forgot to mention there are no BIOS settings at all for fans.

Kernel 3.3? That sounds like a long ways off. I'll just have to hope that the problem magically goes away after some future kernel update!

[eneville]

Thanks for replying!
Kernel 3.3? That sounds like a long ways off. I'll just have to hope that the problem magically goes away after some future kernel update!

Hi Telkwa,

With Ubuntu 11.10 I notice the fan goes to full crank almost 3/4 the time, the rest of the time the laptop appears to act normally. Has this problem magically gone away for you? I noticed from dmesg:

Code: Select all

[    0.000000] ACPI: BIOS bug: multiple APIC/MADT found, using 2
[    0.000000] ACPI: If "acpi_apic_instance=0" works better, notify linux-acpi@vger.kernel.org
[...]
[    0.167727] [Firmware Bug]: ACPI: BIOS _OSI(Linux) query honored via cmdline


To begin with I didn't have acpi_apic_instance specified in the kernel parameters, the last attempt I gave this as acpi_osi=Linux acpi_apic_instance=2 (tried 0 too as the message suggests) but to noavail.

[eneville]

FWIW, I just compiled the latest kernel from kernel.org and the problem has gone. So, gone from Ubuntu's 3.0.0-12-generic (buildd@vernadsky) to a make-kpkg kernel of 3.3.4. I've booted the system several times tonight, not once has it come up with an over excited, noisy fan.