Matthew Wilcox wrote:

quoted text
> On Sat, Jan 12, 2008 at 08:42:48PM -0800, Arjan van de Ven wrote:

>> Wanne bet there'll be devices that screw this up? THere's devices that even screwed

>> up the 64-256 region after all.

>

> I don't know if they 'screwed it up'.  There are devices that misbehave

> when registers are read from pci config space.  But this was never

> guaranteed to be a safe thing to do; it gradualy became clear that

> people expected to be able to read random registers and manufacturers

> responded accordingly, but I don't think you were ever guaranteed to be

> able to peek at bits of config space arbitrarily.

Quite correct...  Reading registers can have all sorts of side effects,

for example clearing chip conditions.
	Jeff
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