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Subject: Re: PCI PM: Restore standard config registers of all devices early
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>,
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Date: Tue, 03 Feb 2009 12:46:46 +1100
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> 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.