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AMD Releases Additional R600 GPU Programming Documentation

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  • glisse
    replied
    Originally posted by chrisr View Post
    There are far simpler programs than Compiz that have trouble with the Mesa R300 driver. Try the "rubik" hack from xscreensaver, for example...

    And I'm not sure if this message is trying to warn me of a driver bug or a hardware limitation either:

    Has any of the new documentation allowed for the R300 driver to be enhanced further without reverse engineering?
    Well as a programmer who did spend quite bit of time on r300 i would say that current r300 driver is dead end. The code is ugly, wrongly designed and with lot of hack all around. Truly what is needed is a rewrite and i see gallium as an opportunity to do so and do it right from the beginning. Unfortunately we are in a business with short time frame and i am sure more manpower will be put into patching r300 to have somethings working as soon as possible.

    Regarding the problem you face the message is pretty explicit: multi-texturing is broken with dxt compressed texture.

    Leave a comment:


  • highlandsun
    replied
    What info is needed to implement e.g. XvMC support?

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  • chrisr
    replied
    "compiz has resisted fixing"?

    There are far simpler programs than Compiz that have trouble with the Mesa R300 driver. Try the "rubik" hack from xscreensaver, for example...

    And I'm not sure if this message is trying to warn me of a driver bug or a hardware limitation either:
    File r300_texstate.c function r300SetTexImages line 301
    DXT 3/5 suffers from multitexturing problems!
    Has any of the new documentation allowed for the R300 driver to be enhanced further without reverse engineering?

    Leave a comment:


  • bridgman
    replied
    In general the 3d engine is faster these days. That wasn't always the case a few generations ago.

    Leave a comment:


  • agd5f
    replied
    Originally posted by TechMage89 View Post
    My bad, it looks like most of the non-accelerating stuff is trivial. And hardware limited

    Another thought: if the 2d engine is no longer included in the r600, does using the 3d engine for 2d acceleration reduce performance over older cards? Would 2d performance be better? If so, could the same method also be used for older cards that don't require it (eg. R500)?
    You could use the 3D engine for blits, etc. on any of the older cards, it's just a lot more complicated to program. There's a slight bit more overhead using the 3D engine as more state programming is involved, but it's probably pretty negligible in practice. Plus with modern composited desktops you want to use transforms and blends anyway which are not available on the 2D engine. Those come for free (more or less) when using 3D.

    Leave a comment:


  • TechMage89
    replied
    My bad, it looks like most of the non-accelerating stuff is trivial. And hardware limited

    Another thought: if the 2d engine is no longer included in the r600, does using the 3d engine for 2d acceleration reduce performance over older cards? Would 2d performance be better? If so, could the same method also be used for older cards that don't require it (eg. R500)?

    Leave a comment:


  • agd5f
    replied
    The radeon ddx was written with documentation or directly from ati code drops. Really the only things that were reverse engineered were the XPRESS (RS480) chips and that was more trial and error than reverse engineering. The 3D (mesa) code is another matter. r100 and r200 were written with documentation, r300 (covers r400 as well) was reverse engineered.

    The 2D accel code is solid. XAA exposes just about every feature of the 2D engine (fills, blits, image transfers, lines, color expansion, etc.), however, no modern toolkit really uses 2D feature other than fills and blits. As such the only EXA hooks that use the 2D engine are fills, blits, and image transfers. The EXA composite hooks require the 3D engine, so it is a lot more work to get running. We have full support for r100/r200 (in fact it was the HW we used for EXA development since these chips had the best documentation available).

    Leave a comment:


  • TechMage89
    replied
    Ok, ok, maybe the language I used was a little too strong, especially given the fact I don't have a lot of experience with C, but when I see lots of comments like "we can't fully accelerate this operation" or "someone needs to find a better way to do this" I do begin to suspect that the code needs some work. (those are rough quotes, I haven't got the code in front of me)

    Granted, maybe the operations aren't that important, so no one thought them worth the effort to fix, but I'm afraid I'm a bit of a perfectionist .

    Also, I'm not entirely sure what's a silicon problem and what's a coding problem (mainly because I haven't got the docs.)

    I'm an object-oriented programmer by training, so when I try to understand a large amount of code, I try to compartmentalize things, but that doesn't seem to work too well on the radeon driver.

    Maybe I've bitten off a bit more than I can chew and should just go back to application programming .

    At any rate, I regarding EXA, I don't just mean that the performance isn't that good on my card, I mean it's unusable.

    Leave a comment:


  • Svartalf
    replied
    Originally posted by Ze.. View Post
    When I get more time I think I'll start contributing to the driver (even though ewwww plain old c )
    What's wrong with a bit of "C" coding? C++ is nice, but it's got some small issues in it's use with drivers. To be sure, it's not as bad as some make it out to be, but it's easier in some ways to do very, very brain-dead things in C++ when you're talking about code for the driver space on an OS- which is a part of why the Linux kernel crowd vehemently oppose the use thereof.

    As it stands, I've got a couple of things to get off my plate before I can consider doing some stuff- but it's on my shorter list of things to do.

    Leave a comment:


  • Svartalf
    replied
    Originally posted by airlied View Post
    What do you mean looks incomplete and hacky?
    Yow... Guess you told him Dave. Good to see you around here- *I* don't think the work's hacky or kludgy.

    Leave a comment:

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