Re: radeon-pre-2

From: Keith Whitwell
Date: Sat Sep 11 2004 - 03:43:16 EST


Dave Airlie wrote:
2D and 3D _are_ to most intents and purposes different functions. They
are as different as IDE CD and IDE disk if not more so.


stop saying this, it isn't true and hasn't been for years, for the mach64
type cards I'd agree, for something even like the i810 this isn't
true, most cards have two paths (at least), an unaccelerated 2D path via
programmed registers, and an accelerated path via some DMA mechanism, this
isn't a 2d/3d split, you have to use the DMA mechanism for doing some 2d
acceleration and you have to use it for all 3d acceleration normally,

Lots of X DDX drivers use the accelerator for 2d stuff, some fbs use it
for accelerating scrolling, the DRM uses it, this is wrong wrong wrong
wrong...X/DRM at least lock each other out, but the fb just tramps in
wearing its size nines.. so in summary the 2D/3D split exists in peoples
minds (graphics cards designers excepted...)

Yes, it is closest to the truth to believe there is one acceleration engine that does all drawing, and this should ideally have a single owner.

But that doesn't mean that mode-setting, etc, has to be moved into the DRM - for my money that stuff can stay where it is, provided there are some sensible interfaces put in place between the two components.

Keith
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