[Intel-gfx] Possible wrong flushes on SNB

[Lukas Hejtmanek]

Chris,

On Tue, Oct 11, 2011 at 09:01:20PM +0100, Chris Wilson wrote:
> If you are using SNA, the likely cause of the flash is the flush, read,
> modify, write of a fallback. That is we flush pending operations in the
> batchbuffer (likely a fill to the scanout), read back from the scanout
> the just modified region and perform the fallback with the CPU. That
> modification is then queued up to be written out sometime in the near
> future. That delay between the fill and the final write can cause
> flickering.
> 
> By contrast UXA performs its fallbacks inplace and so such flicker
> should not be any more perceivable than any other drawing operation.
> 
> File a bug. If you are using SNA, I'd like to prevent the fallback and
> so avoid the flicker. Or I may have misdiagnosed it entirely, so in any
> case I want sufficient information to reproduce.

I did: #41718 

-- 
Lukáš Hejtmánek