sungem on imac G5

Benjamin Herrenschmidt benh at
Sat Mar 19 23:08:54 EST 2005

On Fri, 2005-03-18 at 15:24 +0100, Markus Demleitner wrote:

> (a) The patch didn't apply cleanly, I had to fiddle in the second
> hunk manually (that one probably doesn't matter at all, I just wanted
> to mention it in case of a regression in the code I don't have)

Yup, it's against current bk

> (b) MACIO_OUT8 uses macio, which g5_eth_phy_reset doesn't define.  Fixed
> it by adding
> 	struct macio_chip* macio = &macio_chips[0];
> to its local declarations.

Yah, I missed that bit, I didn't have time to test compile :)

> (c) There are two warnings remaining that I didn't care to fix (for
> now):
> arch/ppc64/kernel/pmac_feature.c:227: warning: unused variable `flags'
> arch/ppc64/kernel/pmac_feature.c:250: warning: control reaches end of non-void function
> (the line numbers are of course for my version)

I first added a lock then figured it wasn't necessary, so the flag can
be removed. The function should also take a return 0, though the lack of
it is harmless as sungem isn't testing the return value. I'll fix those.
Thanks for testing !

> PS: While I'm here, current progress report on thermal control: I'm
> prototyping a thermal control driver in userspace python right now,
> basically doing PID (though I'm convinced there just has to be a
> better control algorithm for this particular problem).  

Apple uses PID everywhere. I ported their algorithm in my existing
driver, though I'm really not convinced it's the best way to go (Apple
stuff tends to oscillate etc..). However, I don't have the proper
calibration infos to do somehting else, all they give me in the cpuid
eeprom on G5s is the actual factors for the PID algorithm, so I decided
to just re-implement the same algorightm.

> Trouble is
> that I have one fan that doesn't seem to have an effect on the
> temperatures (harddisk fan?  I don't think I can see the hard disk
> temperature, though I have one sensor I cannot interpret at all, plus
> there is one sensor OF reads directly through i2c, which may well be
> the hard disk one).  I'll rip the machine open soon to see where the
> fans are (have been reluctant so far since it isn't my machine).
> Good news: The machine switches itself off if it overheats :-)

Ok, good luck ! Once I finally have access to one of these, I'll try
tracing the darwin kernel with remote gdb to figure out where the sensor
data actually come from.


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