Okay - thats an MFPGT patch from pre-OLPC days. I am the guilty and
dubious party. We changed the API to work better with the timer tick,
and thats the version that ended up in the kernel.
I really wish I could take back this patch, because it keeps coming back
to torment me. We must, as a people, put it behind us and forgot it. :)
It detects 7 timers because of a bug in the code - there really are 8
timers, which the current code correctly identifies.
So the workaround works around the workaround. Fun. I think that Mitch
Bradley verified that if you write the magic MSR when all the clocks are
already clear that bad things happen. The workaround probably adds a
dummy clock in. Notice that the "magic MSR" no longer is in the vanilla
code, and thats the way it should be. If the BIOS doesn't allow use of
the clocks, then we have to live with that.
So, based on everything you are saying, I think its clear that our
problem isn't in the MFGPT, but rather in the timer tick (because, as
you said, the watchdog works). We try to use IRQ 7 for the tick, which
Andres and I totally plucked out of thin air based on what we had to work
with on OLPC. Its totally possible that the TinyBIOS had other ideas.
Please try to boot with nomfgpt, and see which interrupts are free, and
use mfgpt_irq= to change it to something else if 7 is in use. Based on
your findings above, you'll probably need to leave the MFGPT workaround
off from now on.
I'll port the watchdog timer to the new API, and we can use that instead
of the timer tick to just make sure that it isn't the timer that is broken.
Also, hopefully that will cease the stream of angry emails asking me why
the ancient patch doesn't work on a current kernel... :)
Jordan
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