It does not exist on 7450 etc.
It exists on 7410 before version 1.3 .
I have no data on 7400.
It does not exist on 750 etc.

[As my only G4 is a 7410 version 1.3, I won't be affected by this.  Hurray.]

I had it happening on 7400.

The problem itself: if two of thermal assist, decrementer, performance
monitor interrupts happen within 1 cycle of each other, evil things
happen with SRR0 and SRR1, so that the return address becomes
unrecoverable.

Suggested solution:

We can forget about thermal assist, as the TAU on all 74xx is broken
and unsupported.  (Says those same errata sheets).
If necessary, it's possible to disable the decrementer interrupt and have
the performance monitor perform its function.

But I won't run into this, so I'm happy for now :)

We can't disable the DEC that easily as it's the primary timer
source of the kernel ;)

Ben.


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