RE: Athlon64 + Nforce4 MCE panic

["Allen Martin" <AMartin@nvidia.com>]

> CPU 0: Machine Check Exception: 0000000000000004
> Bank 4: b200000000070f0f
> Kernel panic - not syncing: CPU context corrupt
> 
> I tried to decode this:
> 
> # ./parsemce -e 0000000000000004 -b 4 -s b200000000070f0f -a 0
> Status: (4) Machine Check in progress.
> Restart IP invalid.
> parsebank(4): b200000000070f0f @ 0
>         External tag parity error
>         CPU state corrupt. Restart not possible
>         Error enabled in control register
>         Error not corrected.
>         Bus and interconnect error
>         Participation: Generic
>         Timeout:
>         Request: Generic error
>         Transaction type : Invalid
>         Memory/IO : Other

I'm not sure why parsemce says this is a parity error, it's a K8 virtual
northbridge watchdog timeout on an I/O transaction.   In other words a
CPU PIO transaction to some device timed out, the timeout is usually set
to 10s.  Prior to K8 these types of errors would usually be system
hardlocks.

I've debugged a few of these before and they usually end up being IDE
device issues.  The IDE controller is really thin (the ATA registers
actually reside in the device) so for example if the CPU goes to read
the ATA status register of some device and the device doesn't respond,
the PCI transaction won't be terminated and the watchdog will fire.

-Allen

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