>Dropping IoMapTransfer is extremely bad idea. The driver will a) be not
64bit compatible b) will possibly fail on some architectures (chipsets
etc).
Also IoMapTransfer does not incur any significant penalties.
Welcome to the wonderful world of graphics! Every CPU cycle counts. I
believe Klaus is right, if we have a bus master on board, we don’t need to
bother about the OS. And there may be so many reasons that a common 32- and
64-bit graphics driver may not be a good idea, that the compatibility issue
may not be relevant. Actually, some time ago Mark Kilgard published a white
paper on what he called “Direct Rendering”, which consists of rendering from
a Ring 3 OpenGL DLL directly to the hardware, bypassing the whole of Ring 0,
Windows included. That is probably the fastest way to do it, that is, when
we have graphics hardware that can handle it.
According to the AGP2.0 spec, there can be only 1 AGP slot.
AGP is point-to-point connection between master (the video card) and
corelogic (the north bridge).
It needs not be point to point, maybe it’s time to have an AGP++ ? With
textures in host memory, it’d be nice to have lots of bus bandwidth and the
ability to DMA directly from Ring 3 host memory.
As about the speed - yes, I agree. Looks like 2D GDI accelerators are
abandoned due to high speed of AGP/modern CPUs - at least GeForce2MX seems
to have no such.
I don’t know much about NVidia chips, but I’ve not seen one graphics chip
that doesn’t have a very effective 2D accelerator. In fact, I doubt it very
much that a CPU can blt at even a fraction at the speed a fast graphics chip
can.
Alberto.
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