When are machine checks suppose to be recoverable?

David's 8250 cleanup patch made me wondering when are machine checks  
suppose to recoverable?  General class of conditions is what I'm  
looking for here.

Is David's case due to some PCI master abort or something else?

- kumar

On Aug 16, 2005, at 11:21 AM, David Woodhouse wrote:

My dual G4 PowerMac crashes sometimes when it probes for the (absent)
serial ports. Theoretically it's supposed to take a machine check and
recover -- but it doesn't always work like that.