XFree86-DGA

[Albert Cahalan]

On 9/26/07, Daniel Monteiro Basso <daniel at basso.inf.br> wrote:
> Em Qua, 2007-09-26 às 19:29 -0400, Albert Cahalan escreveu:
> > The simple Xlib calls would be:
> > loop{
> > 1. app writes to inactive private buffer
> > 2. app asks X to copy that buffer to video memory
> > }
> > That's a whole worthless copy.
>
> Actually that would be:
>
> loop{
> 1. app write to a memory buffer
> 2. app asks X to do a hardware blit to the video memory using the XVideo
> extension
> }

That's a bit better.

Of course, in this case "video memory" is system memory.
The copy is costing memory cycles that would be better
used by the CPU.

Does it in fact work that way on the XO? I thought that the XO
was using a software copy because the kernel driver wasn't
providing the sort of virtual GART (the horribly-named "DRM")
required to make DMA workable.