Re: Kernel virtual memory?

Systemkennung Linux (linux@mailhost.uni-koblenz.de)
Sun, 10 Aug 1997 23:51:08 +0200 (MET DST)


> > Drivers should in the near future be able to DMA directly into
> > userspace memory. We need to lock down the pages involved, and be able
> > to send a "list of pages" for the driver to use.....
>
> This code already exists, its mmuio.c from the Linux/ATM code and is needed
> into 2.2 for this and for the bttv driver (Hauppauge win/tv pci etc). I
> don't know when Werner will be merging the ATM code but hopefully soon

We'll also need this for certain types of SGI video cards. You can't
write directly to the frame buffer's memory, you just can do DMA to it.
Copying to the kernel space and the doing DMA would be a major slowdown
of the GFX performance.

Ralf