New acceleration architecture

Thomas Winischhofer thomas at
Wed Jun 29 09:10:21 PDT 2005

Hash: SHA1

Eric Anholt wrote:
> On Wed, 2005-06-29 at 11:29 +0200, Thomas Winischhofer wrote:
>>- - offscreenByteAlign: Boundary for pixmap data, ie to what boundaries
>>data to be blitted is to be aligned to (in bytes)
>>- - offscreenPitch: Alignment of pitch of pixmaps to be blitted/filled (in
> Yep, got those right.
>>- - maxX, maxY = maximum width/height (and not strictly "coordinate
>>limitations", since in exaTryDriverComposite() you compare the
>>width/height to these values)? Haven't check all occurances of maxX/maxY
>>usage, but I would assume these values really mean
>>  maxX = min(card's maximum X coordinate, card's maximum width)
>>and likewise for Y.
> I'm concerned about how maxX/maxY are handled.  I definitely thought
> they should be the coordinate limitations: the maximum offset in X and Y
> from the beginning of a pixmap (the offset, aligned to
> offScreenByteAlign) for anything touched by an operation.  Instead, they
> seem to be the maximum width/height requested for an operation, which
> isn't quite what we need.
> I imagined the maxX/maxY as slicing all pixmaps at those intervals
> (which should make POT alignment happy, assuming the limit is a power of
> 2 itself), and then doing composites with rectangles of those slices
> according to how the src/mask/dst x/y offsets fell.  The driver would
> adjust its offset for rendering by intervals of maxX/maxY on these
> operations, not having to worry then about whether it would hit the
> coordinate restrictions.  It didn't sound like fun to write, but at
> least a pretty sane way of going about it while respecting the various
> alignment restricitons on cards and without having your Render
> acceleration just stop accelerating on large screens (say, a MergedFB
> desktop).
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Subject: Re: New acceleration architecture
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Thomas Winischhofer wrote:
> One more thing: PrepareCopy is supposed to be given boolean "reverse"
> and "upsidedown", but from CopyNtoN is called with some integer "dx" and
> "dy"...
> Can there be overlapping blits in this concept, requiring "reverse" and
> "upsidedown" (which specify the drawing direction I assume)?

Erm.. one more thing: The executing calls (Solid(), Copy(), etc) come
without any argument that would allow retrieving pScrn or the like....
just the coordinates. Hm...


- --
Thomas Winischhofer
thomas AT winischhofer DOT net
twini AT xfree86 DOT org
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