Events/XDS2007/Notes

John Bridgman, Matthew Tippet - AMD/ATI

NDA-less 2D specs coming soon, 3D specs coming later, r300 3D specs coming even later
Dedicated developer support team too
Modesetting to use ATOM BIOS for some things: set of data tables, and interpreted code, which means you can do native POST on any architecture. Windows driver and BIOS already using this, so it's very capable (not another VESA).
Legal issues regarding HDCP and DRM video decoding, which means those parts become harder.
AMD using the doc release process to improve internal documentation quality too

Fedora 9 in May/June of 2008
Composite needs to be on by default. What needs to be fixed for that?
GLX needs to obey window redirection
Likewise for Xv
2D acceleration should work, hardware accel all the way through rendering
Need a proper memory manager to tie all these things together
krh has been working on redirected GL
airlied working on getting TTM mergeable into the kernel
cworth been optimising intel EXA and benchmarking
Smooth GUI booting: no mode switches and annoying flashes.
Requires kernel modesetting, which requires TTM.
X thus requires DRM, which hurts the BSDs and Solaris, which don't really have it everywhere.
Life's tough, can't hold back development for OSes which lack development resources.
Some Linux developers want the DRM to become a Linux-only project and not cross-platform anymore, but airlied and others have been admirably resisting this.

Yesterday: Hardcoded crtc to output mappings
2 output limit, randr-like functionality through mergedfb
Today: full randr 1.2 support, all outputs supported, initial mac support
Tomorrow stuff!
- RMX, the panel scaler. Off, full, center, aspect.
- In principle can be used on any output, currently only used on LCDs.
- DVO, external connections for outputs. DAC, TMDS, etc.
- Needed for external TMDS. x86 legacy bios has external TMDS table.
- Non-VBE posting. Code for legacy BIOS that doesn't quite work.
- ATOM BIOS should get this for free with the new parser.
- ATOM parser should get folded into radeon too.
- Planning to merge r128 into radeon.
- Probably want to split mach64 out and drop the old ATI wrapper
- Composite transforms need fixing on R100 and R200 so rotation works
- More TV-out modes, fix PAL, random bugfixes
Day after tomorrow
- TTM. Needs DRM support. airlied did some experimental work.
- R300/R400 Composite. Render accel and rotation support.
- PCI rework, kernel modesetting.

Render has good text handling, but is quirky and complicated
So what gets used? Composition, rasterisation, transforms and gradients
What is easy to accelerate? Composition, transform, gradients. Rasterisation is a problem.
EXA doesn't require DRI, is self-contained, basic composition is easy
EXA syncs. And syncs. And shares state with 3D engine.
Using the 3D engine from the 2D driver requires writing the code twice.
(long technical discussion about where to put code)
Things that still aren't accelerated: Tesselation, Image effects, Curve decomposition
(lots of head nodding and general planning)

2D driver for i810 through present
3D driver splits at major architectural changes: 830, 915, 965
Include old hardware support for new features
Test environment includes at least one of each chipset
Ship new features when ready
BIOS-free modesetting, hotplug monitors, rotation, other randr1.2 hotness
TV-out supported on all mobile chips
Current driver: OpenGL 1.5, overlays on hardware that has it, textured video on everything else
Next driver: OpenGL 2.1, HW MPEG decode, output scaling, HDMI, power savings
DFGT, DRRS, DPST, D2PO. Magic acronyms with no definition.
OpenGL performance measurement and tuning planned
Future media: MPEG iDCT, VLD, H.264, VC-1, de-interlace, etc.
Output support: kernel modesetting, eliminate POST on S3 resume
Moving to TTM and new memory manager, lots of optimisation there
GLSL with minor issues. TTM mostly working. Shipping GL 2.1 by January.

http://cworth.org/tag/exa/
Cairo adoption: gnome (librsvg, poppler, evince), mozilla, webkit-gtk
Stack: app, cairo, Render, EXA
Benchmarks! Wouldn't those be nice
- cairo-perf: git://git.cairographics.org/git/cairo, make perf. synthetic, micro
- x11perf. synthetic, micro, very poor Render coverage
- mozilla trender. http://cworth.org/trender_bookmark/. real, macro.
Results. EXA does blit and solid fill really really well.
EXA is a slowdown for trender, which is primarily a glyphs benchmark.
i965 problems. hidden RMW cycles, synchronous compositing, pinned glyphs.
Improvements. Fixed RMW cycles.
Posted patches to store glyphs as pixmaps and eliminate some fallbacks
Idea for "PolyComposite" hook.
Future work: memory management, fallback elimination, transforms
Want to do trapezoid/polygon rasterisation and gradients in hardware too

Performance is really bad. How can I help?
Gamers want high performance, aren't finding it in OSS drivers
R100 was released in 2000, didn't get HyperZ until 2004
gears is ~twice as slow on linux than windows for 945GM
(sysprof profile, technical discussion about implementation details)
Need better documentation for GPU instruction sets
Ideas
- Cross-platform performance and conformance test suite
- Test farm with all supported hardware for regression testing
- Driver developers should work from beginning of product development