Kernel 2.4.23 passive cooling
Hi!
Passive cooling still seems a little strange, at least to me on my Asus L3800C notebook.
What happens:
- active cooling is perfectly fine and I succesfully use
speedstepdaemon to automatically set my CPU to lower performance in idle mode.
- passive cooling works until it reaches the first hot state. After
that the fan(s) power up for a very short time and the CPU performance is set to maximum (!) again. The performance setting can afterwards not be reset to low performance anymore; it will be reset to high automatically!
- Changing back to active cooling restores the machine into a normal
"cool" state but still leaves the performance unchangeable. Only fix is to reboot (I have ACPI fix in kernel).
So basically for me passive cooling is not usable. I think this is a bug in the hysteresis handling in the thermal zone management.
Is there any chance that this will be fixed?
Or is this a BIOS bug?
CU
nils faerber
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Thus wrote Nils Faerber:
Quoted 3 lines
Hi!
Passive cooling still seems a little strange, at least to me on my Asus L3800C notebook.
[...]
Quoted 5 lines
- passive cooling works until it reaches the first hot state. After
that the fan(s) power up for a very short time and the CPU performance is set to maximum (!) again. The performance setting can afterwards not be reset to low performance anymore; it will be reset to high automatically!
Use the limit interface instead of directly manipulating the CPU0/performance -- this *may* help.
Quoted 2 lines
Is there any chance that this will be fixed?
Or is this a BIOS bug?
I'm not sure, but I haven't really had enough time to trace the appropriate AML codepath -- I can obviously also experience the problem. Oddly enough, the first time I booted ACPI 20031002 (just in order to see if improved index field access will fix the passive cooling problem), the processor went up to about 83 C without the fan kicking in (I can't remember if throttling was on at that time, but I guess it should have been). I then switched to active (the fans started spinning like mad), and back to passive, which apparently didn't stop the fans.
What I suspect is that there are some semi-obscure things going on in the AML and it would take me at least two or three cups of coffee to trace it. I'll see what I can do.
Note: most of the thermal management is done by the AML and not by the OS, as th OS doesn't know about most tresholds.
Best regards,
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Karol 'sziwan' Kozimor sziwan-DETuoxkZsSqrDJvtcaxF/[email protected] ------------------------------------------------------- This SF.net email is sponsored by: SF.net Giveback Program. Does SourceForge.net help you be more productive? Does it help you create better code? SHARE THE LOVE, and help us help YOU! Click Here: http://sourceforge.net/donate/
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Thus wrote Karol Kozimor:
Quoted 3 lines
What I suspect is that there are some semi-obscure things going on in the AML and it would take me at least two or three cups of coffee to trace it. I'll see what I can do.
Oh, and it would *very much* help me if I knew how to make _all_ thermal events visible and reported (be it through /proc/acpi/event or at least through a debug switch), and not only the 0x81 ones (hint hint!). Best regards,
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Karol 'sziwan' Kozimor sziwan-DETuoxkZsSqrDJvtcaxF/[email protected] ------------------------------------------------------- This SF.net email is sponsored by: SF.net Giveback Program. Does SourceForge.net help you be more productive? Does it help you create better code? SHARE THE LOVE, and help us help YOU! Click Here: http://sourceforge.net/donate/