Thermal trip points set too low, CPU throttling

jkastelic · 2011-03-27 06:47:06

I have a problem with ACPI on HP Compaq 6715s, because at 15.9°C the passive cooling mode is activated and according to /proc/acpi/processor/CPU0/throttling I only have 12% of the 2200 MHz available and that (like having a 264 MHz processor) is exactly how the computer is behaving. The kernel flag acpi=off "solves" the problem and restores the performance; but with acpi disabled fan control is also disabled, meaning I must watch the temperatures manually to prevent overheating.

The problem started on some update, the details of which I don't remember. On Debian 6.0.1 the trip points are normal, that is the same as before the offending update on Arch. I first thought that by installing 64-bit Arch I would solve the problem and updating did bring a small performance increase. I have the old kernel saved in pacman cache (which I have a backup of) but I cannot install since it is 32 bit. If those trip points can't be changed, I will install a 32-bit Arch again and try the old kernels (currently I have 2.6.37 64-bit kernel, in the old cache I have 2.6.35.8 and newer 32-bit kernels).

The question is now how to change ACPI thermal trip points from 15.9°C back to some normal value; I think the passive mode should start at 90°C or at even higher temperature. Cooling the computer is out of the question since the room where the computer is has a temperature of 21°C.

shulamy · 2011-03-27 20:33:01

what about the bios?

ezik

itman · 2011-03-28 09:00:56

What other boot parameters are in use?

acpi_osi=Linux

Just an idea.

Korrode · 2011-03-28 09:53:43

Ahhh good old HP and their incorrect ACPI temperature/voltage limits tables.

I once worked on a HP Pavillion that had some entries in the table where the minimum acceptable temperatures/voltages was set HIGHER than the maximums... literally like they'd let a monkey bash the numpad for the table entries.

As shulamy mentioned, the BIOS is where those tables are stored and your only possibility for fixing it (other than BIOS hacking) is with updating the BIOS.

(Sidenote: that system I worked on had no updated BIOS with fixed tables available, and the only way I could solve the problem of the CPU fan spinning too slowly when temp-based fan speed throttling was on, but whining at an unnecessary 6000rpm when it was switched off, was to replace the 6000rpm max fan with a 4500rpm fan and leave temp-based throttling turned off.

Moral of the story: HP are imbeciles, don't buy their products.)

vacant · 2011-03-28 10:29:06

jkastelic wrote:

with acpi disabled fan control is also disabled, meaning I must watch the temperatures manually to prevent overheating.

Is this true? Anyone? I thought the BIOS would switch the fan on full regardless when the passive trip point is passed. So your temp may go up to (e.g.) 80C with no fan, then it kicks in at full speed.

Also, "thermal" module has a parameter "act" (integer) to disable or modify the lowest active trip point - try

options thermal act=45

in /etc/modprobe.d/modprobe.conf and reboot.

jkastelic · 2011-03-28 16:11:54

shulamy and Korrode: I wouldn't update BIOS since the trip points are normal in Debian and also were in Arch before the update (I will try downgrading the kernel if all else fails, but then I won't have the newest kernel ).

itman: How do I check other boot parameters? In /boot/grub/menu.lst on the "kernel" line the only other parameter is "ro".

vacant: Fortunately you are right (I heated the system with 20 dd processes copying /dev/urandom to /dev/null and the fan did kick in at full speed at 84°C). So I won't harm my computer by not running acpi ... however, I don't know how to check battery status without acpi. Does anyone know that?

Adding the "options thermal act=45" line to modprobe.conf didn't change anything, even when I added the "thermal" module to rc.conf or tried modprobing it manually.

itman · 2011-03-28 16:49:04

the just add on that kernel line after "ro"

acpi_osi=Linux

reboot and the new kernel-parameters are in effect.

happy rebooting

jkastelic · 2011-03-28 17:12:23

New kernel parameters are in effect but the trip points are unchanged. Still 15.9°C is the trip point for all modes except critical, which is 105°C.

vacant · 2011-03-28 19:01:35

jkastelic wrote:

I don't know how to check battery status without acpi. Does anyone know that?

Blacklisting? Try !thermal in rc.conf. Maybe try !fan as well/instead.

jkastelic · 2011-03-28 22:30:58

Blacklisting thermal did the trick and now the system is "fully" functional. Thank you all for the ideas. As for me, the case is closed.

Arch Linux

#1 2011-03-27 06:47:06

Thermal trip points set too low, CPU throttling

#2 2011-03-27 20:33:01

Re: Thermal trip points set too low, CPU throttling

#3 2011-03-28 09:00:56

Re: Thermal trip points set too low, CPU throttling

#4 2011-03-28 09:53:43

Re: Thermal trip points set too low, CPU throttling

#5 2011-03-28 10:29:06

Re: Thermal trip points set too low, CPU throttling

#6 2011-03-28 16:11:54

Re: Thermal trip points set too low, CPU throttling

#7 2011-03-28 16:49:04

Re: Thermal trip points set too low, CPU throttling

#8 2011-03-28 17:12:23

Re: Thermal trip points set too low, CPU throttling

#9 2011-03-28 19:01:35

Re: Thermal trip points set too low, CPU throttling

#10 2011-03-28 22:30:58

Re: Thermal trip points set too low, CPU throttling

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