OSDev.org

Hello.

It seems impossible to make the dma write in the video buffer.

I heard vmem is a window in the card's memory, so perhaps that's why it can't work?

Adrian.

in the old days, it was faster to use dma transfers to get stuff into the video memory for games than direct memory copies... so it can be done.

i cant think of a reason why it cant be done today, since its just another memory hole.

iirc.. not 100%, you have to give it a physical address, so if your in pmode and you have virt mapped memory, you cant give it a logical address.

You can write to a video buffer, you just need to map it to memory adress space using PCI or AGP interface. Usualy OS put this memory at the end of physical(RAM) memory.
Anton.

It's possible, but not overly useful, now-a-days.

I've heard of projects like this a few years back, but most came to the conclusion that writting directly to video memory is a lot less hassle and, in fact, faster (with 32 or, now, 64-bit writes).

Cheers,
Jeff