Comment 52 for bug 1290110

(In reply to Zhang Rui from comment #21)
> (In reply to Pohjoistuuli from comment #19)

Sorry for answering quite late. I am usually busy during the week and testing this is surprisingly time-consuming (waiting for the system to have the right start temperature and then then waiting for it to raise etc). I use now tmon, which makes testing the thermal behaviour of laptops much easier. It is also a quite handy tool to regulate the fan speed. I raise the CPU-temperature usually with 'openssl speed'. Finding this 'technique' improved testing speed quite much.

> Anyway, please attach the acpidump of your machine, so that I can check if
> they are the same AML problem.

The acpidump is now on my harddrive, but I did not find a function to attach a file to this message. I run also a check with fwts on my machine (on Ubuntu 14.04). fwts reported problems in the DSDT. I can provide also this log if needed (and when I know how ;-).

> BTW, it would be nice if you can try 3.12 kernel to verify if this is a
> regression or not.

I have checked out ArchLinux kernels 3.12.9-2 and 3.13.1-1. 3.12.9-2 runs fine and 3.13.1-1 does not regulate the fan speed when passing an active trip point temperature. Other ArchLinux kernels that I have tested so far are 3.10.37-1 (lts), which works fine, and 3.14.1-1 (today's kernel), which does not regulate the fan speed.

Some other remarks:
- I can confirm Manuel's observations regarding cdev*_trip_point. I can see also all three numbering versions on my laptop (version 3 on Ubuntu 14.04, which has the the acpi routines compiled in the kernel). tmon does not have any problems with this and shows under kernels 3.10, 3.12., 3.13 and 3.14 the same setup and works without any differences. Additionally checking dmesg did not reveal relevant differences between 3.12 and 3.13 to me.
- My machine has a thermal zone GFXZ (acpitz0), which isthat not connected to any hardware because my computer has only chipset graphics. The 'temperature' is constant at 16'C. Is this perhaps a problem in this context? Is the acpi system looking only at the wrong thermal zone?
- The behaviour of my machine is different when on battery and when on AC. The reason for this is a BIOS setting, which affects the lowest fan speed level. On battery, it is always 0% rpm (= completely off). When on AC, it is possible to choose in the BIOS between 0% rpm (like when on battery) or 20% rpm as minimum value (my setup). This difference between AC and battery made remarking this error in the beginning quite difficult.
- For cooling my machine at normal CPU load, 20-30% rpm are often sufficient. Under full load, the CPU temperature rarely exceeds 60'C when the fans are running with 45% of max. rpm. Therefore, problems with overheating and fan regulation were first quite confusing.
- tmon is really nice - including the user interface!!!

Thanks for looking into this, Thomas