[Mesa-dev] [PATCH] i965: Mark all EGLimages as non-coherent.

[Chris Wilson]

Quoting Kenneth Graunke (2017-08-16 20:30:21)
> EGLimages are shared with external users, and we don't know what they're
> going to do with them.  They might scan them out.  They might access
> them in a way that doesn't work with our explicit clflushing.
> 
> It's safest to simply mark them non-coherent.
> 
> Chris Wilson caught this problem and wrote a similar (though less
> aggressive) patch to solve it; the miptree code has since undergone
> a lot of refactoring so I had to rewrite it.

I checked that this does fixup the glamor framebuffer to be marked as
!cache-coherent so with this we stop trying to write into it using the
WB mapping. With the always use LLC for reads patch applied, there isn't
a noticeable penalty for glamor on llc from a brief 2 minutes of looking.
If there are, those will need to be fixed for !llc platforms anyway, so
the more the merrier?
 
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Jason Ekstrand <jason at jlekstrand.net>
Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
-Chris