Re: [RFC&PATCH 1/2] PCI Error Recovery (readX_check)

[Benjamin Herrenschmidt <benh@kernel.crashing.org>]

> The "good news" is that I doubt very many drivers will care enough to do
> this. I suspect you'll only have a few very specific drivers used in 
> fault-tolerant circumstances, where you care more about the errors than 
> about the inevitable serialization.

Yup, but then, the user have to take care that behind a single "error
checking" entity (a bridge for example), all devices have such drivers
that honor the bridge-level locking and not their own.

On ppc64, I think we always have 1 bridge = 1 slot though, makes things
easier (well, provided we don't start to try playing with error coming
from slots on the g5).

> > I don't know what is the best thing to do here... The arch is the one to
> > know what is the granularity of the error management (per slot ? per segment
> > or per domain ?) and so to know what kind of lock is needed...
> 
> It will have to depend on the bus setup. Not arch-specific per se, but 
> clearly specific to the bus controllers in question. 

Right.

Ben.