[PATCH 0/5] Add tiling support for r6xx/r7xx

[Michel Dänzer]

On Die, 2010-05-25 at 19:09 -0400, Alex Deucher wrote: 
> 
> Also, on r6xx/r7xx, we don't enable tiling of the front buffer as
> that would require the use of wfb or tiled to untiled blits for CPU
> access. Tiled to untiled blits works (I've tested it), but shows an
> approximately 40% performance hit for software fallbacks (tested with
> non-aa text in x11perf).  I'm not sure what how that compared to sw
> detiling with wfb since the algo is pretty complex.  In practice, I
> didn't notice any difference in performance on the desktop.

How exactly did you implement the (un)tiling blits? I'd suggest doing it
similarly to the way we're handling byte swapping with KMS on big endian
machines: return FALSE from the PrepareAccess hook and handle the
(un)tiling in the DownloadFrom/UploadToScreen hooks.

In my experience, wfb is excruciatingly inefficient (one callback per
byte in the worst case).


-- 
Earthling Michel Dänzer           |                http://www.vmware.com
Libre software enthusiast         |          Debian, X and DRI developer