RE: Using video memory as system memory

[Geert Uytterhoeven]

On Wed, 10 Apr 2002, Byron Stanoszek wrote:
> On Wed, 10 Apr 2002, Holzrichter, Bruce wrote:
> > That is a neat idea, though.  The PCI/AGP bus may be a limiting factor for
> > this as well, correct?  As far as speed, I believe most video cards have
> > fast memory, vram, or sram, but it's only useful transferring between the
> > Video GPU, and Video cards memory, as the bus to the video card is the
> > bottleneck.
> 
> Yeah. In fact in some responses the 'slow speed' consideration was so much that
> they all say I'd be better off writing a block driver and making use of the
> memory more as a swap device rather than as system RAM.
> 
> Has anyone out there done this yet? I figure I'd ask before reinventing
> anything.. :)

drivers/block/z2ram.c does this for RAM in the Amiga Zorro II space.

(Why? Because you cannot use Zorro II RAM as system RAM on machines equipped
 with a Zorro III bus because on those machines Zorro II RAM doesn't support
 read-modify-write cycles.)

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [e-mail]

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds