Fan control for PowerMac7_3 (#3)
H. Peter Anvin
hpa at zytor.com
Sat Oct 16 14:24:05 EST 2004
Benjamin Herrenschmidt wrote:
> Ok, here's a new patch that fixes a few issues, it's been
> tested on a non-liquid cooled system and appear to work ok.
I'm testing it out right now. It is definitely suffering from some
degree of oscillation when idling, and it seems to be one particular
(set of) fan(s) that is having that problem.
Note that one cause of oscillation at low speed is that there is a
minimum speed below which the fans will simply stop. This may be what
is happening here.
Some time later I'll try to figure out which numbers to collect and try
to generate a graph over time.
It's definitely passing the stress test, though; make -j4 on the whole
kernel (with the .config posted earlier) took 4:27.19. The other stress
test -- which used to kill the old thermal driver dead in a matter of
seconds -- is to start a bunch of "cat /dev/zero > /dev/null" is happily
running, and nice and quiet.
The oscillation is obnoxious, though.
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