[cairo] [PATCH, pixman] ARM NEON optimized pixman_blt & overlapped stuff

[Koen Kooi]

On 18-11-09 17:41, Siarhei Siamashka wrote:
> On Wednesday 18 November 2009, Koen Kooi wrote:
>> On 18-11-09 14:41, Siarhei Siamashka wrote:
>>> Making real use of overlapped pixman_blt also requires patching xserver
>>> and the most simple way to do it is included in the attached test patch
>>> (not intended to be applied as-is).
>>
>> How many kittens will get killed if I provide a pixman with overlapped
>> blit support and apply your patch to Xorg after that?
>
> Everything should work fine except that there will be no way for downgrading
> pixman. Patched xserver will show bad image artefacts on the use of overlapped
> blits when run with older unpatched versions of pixman.

Good, I have complete control over both when it comes to the 
buildsystem, so only people that manually tell the package manager to 
upgrade xorg but not pixman will get screwed.

> The other way around is always fine. Patches for pixman have no effect on
> interoperability with any versions of xserver.
>
>> I suspect overlapped blits will also benefit from a cached framebuffer
>> as well, right?
>
> Yes, at least for me the best type of 'non-3d-accelerated desktop' experience
> on OMAP3 devices can be achieved with write-through cached 16bpp framebuffer
> (and ShadowFB option explicitly disabled). But it still needs a few more NEON
> optimizations to address all the bottlenecks.

I've been thinking about enabling the caching when running on 3503/3505 
which have no iva or sgx. Fixing software to flush the cache properly 
would be better, but too many (slow moving) components are involved.

regards,

Koen