[PATCH] Ensure blitter quiescience before reading pixels from the framebuffer

[Alex Deucher]

On 7/18/07, Bernardo Innocenti <bernie at codewiz.org> wrote:
> Alex Deucher wrote:
>
> > FWIW, I've seen similar issues with EXA on savage.
>
> The codepath I'm fixing here cannot be responsible for
> that, but it seems that X is missing protection against
> such races in several places.
>
> In the AMD driver, the problem was in the Composite hook.
> But I see the Savage driver does not even implement it.
>
> There's a readfb() function that lacks protection, but
> apparently it's dead code.

It could just be savage funkiness, but I do get wrong colors for solid
fills sometimes with EXA.  I haven't had time to dig further.

Alex