[MPlayer-dev-eng] Re: Improved DGA vertical retrace sync

[Matan Ziv-Av]

Fredrik Noring wrote:

> To take full advantage of the mplayer DGA driver, busy-waits in
> the XDGASetViewport function in the XFree86 DGA drivers needs to be
> eliminated.

> a long-term solution would
> likely need some other kind of kernel support however.


I implemented this kernel support for retrace interrupt. It is part of
the kernel code in svgalib. To use it download svgalib-1.9.16, and
install svgalib_helper (the kernel module).
Then, after openning the correct device (/dev/svga1, if you only have
one video card), issuing an ioctl(SVGALIB_HELPER_IOCWAITRETRACE) will
block until the retrace.
This is independent of the rest of svgalib, and works also in text mode
or X11.
The kernel code currently works on ATI cards, Matrox cards, and some NV
cards (Riva 128 included). It should work on any vga compatible card, if
it is the only card in the system, but it does not work on all cards.


-- 
Matan Ziv-Av.                         matan at svgalib.org