Hi,
I would like to adjust the temperature at which the fan starts, because as
it is now it runs continuously, at low speed but this continuous noise
bothers me. I'd rather have it spin faster and intermittently. This is an
HP laptop.
I've read much (mostly Q&A pages and list threads, regular documentation
seems to be scarce), and investigated the behaviour of files in
/sys/devices/virtual/thermal . From what I understand there's no bug, just
the temperature thresholds are not to my taste.
More specifically, there are 7 cooling_device's (4 of type Fan, 2
Processor, 1 LCD) and 5 thermal_zone's (the first 4 really are
temperatures, the last is the fan speed). thermal_zone0 controls the fan.
The lowest trip_point_?_temp (?==4) is 45000, which is very low.
Basically, after a few minutes of idle operation temp reaches 50000 or
55000 (looks like there is 5 °C granularity) and never gets lower: I've
tried and manually set the fan to speed 2 (echo 1 >
cooling_device2/cur_state), even then temp doesn't decrease below 50000.
trip_point_?_temp are not writable. I've set thermal.act=60000 in the
kernel command line, to no avail; is this supposed to be reflected in the
trip_point_?_temp files? (Note: trip_point_[1-4]_type is "active".) This
is kernel 3.2.71 .
What can you advise me to do now?
And by the way, for my education:
- how are the trip_point values determined?
- how is hysteresis implemented? I mean, you don't want your fan speed to
change every other second, so the "speed up" threshold has to be higher
than the "speed down" one. In fact, I've found no explanation of how the
trip_point values are used.
Thanks.
--
Lucas Levrel
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