[MPlayer-dev-eng] MGA Xv sux...

[Arpi]

Hi,

> > > dma transfer support tp mga_vid/vidix/fbdev. I think SDL (which is
> > i doubt it. sdl is an userspace lib... dma requires kernel space and
> > deep knowledge of chip details. maybe directfb does it, i remember reading
> > it somewhere, but i'm not sure.
> 
> Oh, I bet SDL just does accelerated video-to-video blits. That would
I doubt it. What does 'accelerated blit' mean? It could be either CPU (memcpy
maybe using MMX) or DMA (let the hardware to do that). I can't imagine any
other method... and SDL is just broken unoptimized shitty code anyway so
i really doubt it has something interesting we don't have...

> be a lot easier and wouldn't need dma. My fault for being stupid and
> not thinking.
> 
> Anyway the Matrox tech docs *do* seem to provide enough information
> for anyone interested in implementing dma on mga_vid. Programming the
yes

> card for it doesn't seem to be that hard -- but of course like you
false

> said all the host-side stuff and kernel hacking required is likely to
> be hell.
yes

it requires proper memory allocation (page aligned, linear physical emmory
map), IRQ handling (dma finished), locking of resources (to avoid crash by
DRI or other dma stuff) etc... for DRI supported cards the DRM kernel
modules provide such functionality (the rage128 dma Xv uses that) but using
it is not trivial and needs fixes/changes as it was not designed for this
purpose (it is usually limited to few 64k, enough to 3D command buffer)

feel free to implement...


A'rpi / Astral & ESP-team

--
Developer of MPlayer, the Movie Player for Linux - http://www.MPlayerHQ.hu