[Intel-gfx] [PATCH] drm/i915: Set persistent-mode for SNB framebuffer compression

[Chris Wilson]

On Mon,  4 Jul 2011 13:35:57 +0100, Chris Wilson <chris at chris-wilson.co.uk> wrote:
> Persistent mode is intended for use with front-buffer rendering, such as
> X, where it is necessary to detect writes to the scanout either by the
> GPU or through the CPU's fence, and recompress the dirty regions on the
> fly. (By comparison to the back-buffer rendering, the scanout is always
> recompressed after a page-flip.)
> 
> This fixes the missing rendering oft triggered in the past, but easily
> reproduced by using mutter with sna, for which the current workaround is
> to disable fbc entirely.

Hah. Spoke too soon, actually testing it, it seems the fix was due to the
little buglet in the first patch which had the effect of disabling FBC.

Oh well, it was a nice idea.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre