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

[Alex Deucher]

2010/5/27 Michel Dänzer <michel at daenzer.net>:
> 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.
>

I used that exact method.

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

It's horrible.  There's also no way to handle multiple cards sanely as
there's nothing to attach a driver priv to.

Alex

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