[SDL] Asynchronous Blit results

Sam Lantinga slouken at devolution.com
Fri Apr 14 13:01:47 PDT 2000


On Wed, 05 Apr 2000, Pierre Phaneuf wrote:

> 
> I think that all the versions of DGA are restricted to full-screen.
> 
> What is *really* interesting is that new DRM module in the 2.3.x
> kernel... Hmm... This is exactly how direct rendering works: the DRM
> module allows the X client to do mmap/DMA to the video hardware (with
> authorization from the X server), letting it do its own clipping for
> windowed mode. This also means that a full duplicate of the video driver
> has to be available to the X client, but this can be hidden in a library
> (like libdri.so does).
> 

Does this mean that under linux 2.4 + XFree4.0 you will get the mmap()ed
windowed access ? would really rock. 

That is exactly that what we would need to get windowed full-motion
performance under high load:
the low-latency patches already allow for <5ms latencies WORST CASE,
regardless of the load.
That means if your DVD software decoder takes 50% of the CPU,
you could watch dropout-free video while doing heavy computations or
disk I/O in the background, just as with a hardware decoder.
That would be too cool, since the same concept applies to games.
(You play a game which takes <100% of the CPU at full speed/smoothness,
regardless of the background system load)

Benno.


> -- 
> Pierre Phaneuf
> Systems Exorcist




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