Re: [PATCH 1/1] pci: Block config access during BIST (resend)

Benjamin Herrenschmidt
2005-01-16T22:23:47Z

On Sun, 2005-01-16 at 23:07 +0100, Andi Kleen wrote:
> > What is complex in there ? I agree it's not convenient to do this from
> > the very low level ones that don't take the pci_dev * as an argument,
> > but from the higher level ones that does, the overhead is basically to
> > test a flag in the pci_dev, I doubt it will be significant in any way
> > performance wise, especially compared to the cost of a config space
> > access...
>
> For once you cannot block in them. There are even setups that
> need to (have to) do config space accesses in interrupt handlers.
> The operations done there should be rather light weight.

I don't think we ever want to block in that sense. I think all we need
is the "filter" mecanism, that is drop writes and return cached data on
reads when the device is "offlined"...

Ben.