Re: PCI PM: Restore standard config registers of all devices early

Benjamin Herrenschmidt
2009-02-03T01:47:28Z

> Note how the PCI layer (currently) only saves the low _16_ dwords of
> config space (64 bytes). The radeonfb code that did it by hand saved the
> whole 64 dwords (256 bytes). It _probably_ doesn't matter, but..
>
> The reason the PCI layer only does 64 bytes is that that was the really
> old PCI config space model - the rest was undefined and apparently a few
> cards reportedly even crashed when accessing it (but who knows, that may
> be urban folklore).
>
> But if that patch works for you, it's clearly already better than _not_
> applying the patch, so..

Radeons don't do much with config space... the worst we may miss I
suppose is subsystem vendor/device... Maybe I'll add something to
explicitely save and restore it or X might get upset. I'll have a look.

At some point, that whole code will migrate out of radeonfb into the new
radeon DRM with kernel mode setting in which case even X should stop
caring ... mostly.

Cheers,
Ben.