README
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2 * Copyright 2009-2011 VMware, Inc. All rights reserved.
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24 *********************************************************
25 * Authors:
26 * Zack Rusin <zackr-at-vmware-dot-com>
27 * Thomas Hellstrom <thellstrom-at-vmware-dot-com>
28 */
29
30The XA gallium frontend is intended as a versioned interface to gallium for
31xorg driver writers. Initially it's mostly based on Zack Rusin's
32composite / video work for the Xorg gallium frontend.
33
34The motivation behind this gallium frontend is that the Xorg gallium frontend has
35a number of interfaces to work with:
36
371) The Xorg sdk (versioned)
382) Gallium3D (not versioned)
393) KMS modesetting (versioned)
404) Driver-private (hopefully versioned)
41
42Since Gallium3D is not versioned, the Xorg gallium frontend needs to be compiled
43with Gallium, but it's really beneficial to be able to compile xorg drivers
44standalone.
45
46Therefore the xa gallium frontend is intended to supply the following
47functionality:
48
491) Versioning.
502) Surface functionality (creation and copying for a basic dri2 implementation)
513) YUV blits for textured Xv.
524) Solid fills without ROP functionality.
535) Copies with format conversion and - reinterpretation but without ROP
546) Xrender- type compositing for general acceleration.
55
56
57The first user will be the vmwgfx xorg driver. When there are more users,
58we need to be able to load the appropriate gallium pipe driver, and we
59should investigate sharing the loadig mechanism with the EGL gallium frontend.
60
61IMPORTANT:
62Version compatibilities:
63While this library remains OUTSIDE any mesa release branch,
64and the major version number is still 0. Any minor bump should be viewed as
65an incompatibility event, and any user of this library should test for that
66and refuse to use the library if minor versions differ.
67As soon as the library enters a mesa release branch, if not earlier, major
68will be bumped to 1, and normal incompatibility rules (major bump)
69will be followed.
70It is allowed to add function interfaces while only bumping minor. Any
71user that uses these function interfaces must therefore use lazy symbol
72lookups and test minor for compatibility before using such a function.
73