PowerMac G5 running 11-current kernel fails to read temperature sensors

[Jukka Ukkonen]

Hello all,

Just a quick question... Has anyone else tried to build
a ppc64 (GENERIC64) kernel locally on a PowerMac G5
during the last month or so?

When booting the CD snapshot kernel of Oct 2nd there
are no worries. Then again when I try to use a locally built
kernel using the latest sources from head, the system starts
complaining about I2C read errors and errors when trying to
read max6690 sensors. Those complaints repeat about
5 times after which the system powers down automatically.
There is no genuine risk of overheating, though.
When running the snapshot kernel of Oct 2nd the CPU
sensors show temperatures around 45-50 C. All of the
other sensors including the two max6690 sensors show
values in the range of 25-45 C.

When using the older snapshot kernel all of the temperature
sensors are visible in "sysctl dev" output.
When using the latest and greatest locally built kernel trying
the same sysctl only hangs when it triggers reading of those
sensors while I get to watch the complaints about I2C read
failures.

With the older snapshot kernel the fans keep operating at
relatively slow speeds. With the locally built latest and greatest
kernel the fans keep adding rpms step by step to plain crazy
speeds until the system powers down.

Does this ring any bells? Have there been any changes to
the I2C drivers or temperature sensor drivers during the last
month or so? Is there something I should try to inspect the
issue further?

--jau