Xserve G5 keeps shutting down

[Nathan Whitehorn]

On 06/27/11 09:28, Paul Mather wrote:
> On Jun 25, 2011, at 8:52 PM, Nathan Whitehorn wrote:
>
>>> That's extraordinarily odd. And you said there was no fsck or
>>> other problem after the reboot? It looks like it shut down
>>> normally?
>
>
> Sorry, I probably wasn't clear.  The system does an unclean
> power-off.  I have to fsck when I start it up again.

Ah, OK. That makes infinitely more sense!

> What is odd, to me,  is that this power-off occurred even after
> commenting out the shutdown line in the thermal power management
> driver.  So, it must be something else that is forcibly powering off
> the system, maybe something in OpenFirmware, rather like some PC
> BIOSes will initiate a power-off when temperatures exceed critical.
> But, what is definitely odd is that temperatures don't seem to get so
> high as to be critical, so perhaps it is some other hardware state
> that is triggering the power-off?

Yes, something like that seems likely, either some strange firmware 
thing or the PMU microcontroller becoming unhappy. A few more things to try:
1) Does setting machdep.manage_fans=0 from the loader change anything?
2) Change the pause in powermac_thermal.c line 86 from hz to 2*hz or 
even 3*hz, in case the firmware has a bug similar to the one we used to 
have, and BSD is saturating the I2C sensors so that firmware can't read 
the temperature.
3) Add RackMac3,1 to the list of systems on which the firmware is 
quiesced at line 517 of /sys/powerpc/ofw/ofw_machdep.c

>>> I notice with the pwm-controlled fans that there is a minpwm and
>>> maxpwm (40 and 100 respectively on my system).  Is it possible to
>>> lower the minpwm?  I tried to do so via /boot/loader.conf
>>> (lowering it to 30) but that appears to have had no effect.  Here
>>> is my /boot/loader.conf:
>>>
>>> dev.fcu.0.fans.sys_ctrlr_fan.minpwm=30
>>> dev.fcu.0.fans.pci_fan.minpwm=30
>>
>> I've turned the minimum back down. I had turned it up to 40 due to
>> being frightened by a electronics-burning smell, so that should be
>> fixed too.
>
>
> I'll build a new kernel and see if things improve.
>

Thanks so much for your patience!
-Nathan