Running Slackware 12 on a desktop and a laptop.

Is it normal practice or advisable to configure the system to load the sensors and use them to control fan speed? Am I best off with it or without it? Is it genuinely useful for making the system quieter?

Most laptops usually handle their own cooling settings. Not all work though. You can look under /proc/acpi and the items under to see what there is. Example on mine.
cat /proc/acpi/fan/FAN0/state
Many many files under there but all systems very. Have seen some not show much at all and that is because of using non standard acpi controls.

Brian

And desktops?

alan@Lavankossot:~$ cat /proc/acpi/fan/FAN0/state
cat: /proc/acpi/fan/FAN0/state: No such file or directory

Well the question is. Is there a /proc/acpi/fan/FAN0 directory? Like I said it varies from machine to machine as to what is under /proc/acpi. Desktop do the same as well.

Brian

Not desktop fans are controlled by ACPI. I think, that those who are powered directly from the power supply unit can't be controlled.

It depends on the board but some like tyan server boards can see rpm of the fan. But have not seen any that can actually control the on and off of a fan on Desktop machine.

Brian

most modern fans can be controlled ... run sensors-detect and load the correct modules and then run fancontrol. IT will work fine.

its not done usually cos most modern mobos do this automatically and you don't have to care about it.

This is really confusing. I have a fairly modern setup
ASUS A8N-VM - Nforce 410 PCI-Express Mainboard - Micro ATX
I hear the fan going, I do not know if anything is controlling it. I do not know if there is any point in taking this any further.

I have tried running sensors-detect and then making the changes to my system. I then ran pwmconfig which found two fans which can be controlled. But I do not know which of about five temperature readings each fan control should be looking at or what the temperature readings should be to trigger the fans.

If you don't know, then just let the BIOS handle it. If you don't specifically want to control the fans, it is done automatically by the BIOS.

it is pretty obvious. If the fan speed increases when you heat up the room or reduces when it is really cold outside (additionally when you don't use too much of cpu the fan speed should decrease) then you can know someone is controlling fan speed. If the fan speed remains constant regardless of whether you are compiling the kernel or just reading a txt file then I guess no one is controlling.


your mobo should I think support fan speed control. Open the BIOS Settings (DEL key at startup etc.) and tinker around there somewhere (additionally read the mobo manual).

I have has a look in the Bios. There is something called Athlon Cool N'Quiet which is enabled in the Bios. I believe that there are linux kernel modules that are supposed to deal with us but I have no idea if they are loaded or what to do to get this working.

In the Hardware monitor section there is

CPU Q-Fan control which is disabled. Enabling it gives a range of CPU Fan Ratios including auto and values between 90 and 60%

I have had a look in the Bios. There is something called Athlon Cool N'Quiet which is enabled in the Bios. I believe that there are linux kernel modules that are supposed to deal with us but I have no idea if they are loaded or what to do to get this working.

In the Hardware monitor section there is

CPU Q-Fan control which is disabled. Enabling it gives a range of CPU Fan Ratios including auto and values between 90 and 60%

yeah enabling that should do it imho

Well I believe that I have cool'n'quiet working. Had to uncomment a couple of lines in rc.modules and add a few lines to rc.local. The system monitor shows that cpu frequency drops 50% when idling and temperatures fall as well.

However I cannot hear any change in the fan speed so I suspect that this isn't being handled in the BIOS. I could probably get thos to work with pwmconfig but I am worried about the risk of toasting my processor and I am not sure that it is worthwhile.

the quiet part is what I was talking about. I never thought you also wanted to reduce frequency. Infact, I think there is a KDE widget kcpufrequency or something . Read up on scaling governors and cpu scaling in the kernel documentation. You can change the scaling governor on the fly btw.

changing frequency will get you cool, to get quiet you need to reduce fan speed. run sensors-detect and then fancontrol. To understand which temp sensor is for the cpu, the heuristic I use is that the CPU is generally the hottest temp you will see, the mobo is usually little cooler .

but as I said, play around with your mobo bios, this should all happen automagically by the firmware.