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Audio Support Comes Closer For Newer Radeon GPUs

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  • Audio Support Comes Closer For Newer Radeon GPUs

    Phoronix: Audio Support Comes Closer For Newer Radeon GPUs

    Newer AMD Radeon GPUs are closer to having HDMI audio support with the open-source DRM/KMS driver...

    http://www.phoronix.com/vr.php?view=MTQzNjA

  • #2
    I hope I don't sound ungrateful but something which would be interesting is if/when LPCM 5.1/7.1 Audio will start working for 4xxx/5xxx/6xxx cards. The last time I heard something about it was ~2(?) years ago and back then the status was that it should work soon.

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    • #3
      I'd very much like that, but I've never seenof a roadmap or "soon" either :/

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      • #4
        That requires changes to alsa hda driver. We are looking into it, but it's had a lower priority compared to other projects (UVD, DPM, etc.).

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        • #5
          Originally posted by Henni View Post
          I hope I don't sound ungrateful but something which would be interesting is if/when LPCM 5.1/7.1 Audio will start working for 4xxx/5xxx/6xxx cards. The last time I heard something about it was ~2(?) years ago and back then the status was that it should work soon.
          As Alex said, there are two separate parts to the problem. One is that the audio driver needs to support multichannel, and the other is that the graphics driver needs to mix multichannel audio into the HDMI data stream. The graphics driver part has been done for a while, and that's probably what you heard about.

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          • #6
            I believe 2 years ago radeonhd hdmi audio driver went using the generic intel one.
            Unless I am mistaken, wouldn't that solve the alsa part?

            I am thinking of this patch: [PATCH] ALSA: hda - use generic hdmi parser for ATI R6xx codec, by Ansi.
            More info by him in case I'm missing something:

            It is worth noting (though you probably knew already) that the stuff in
            the public HD audio spec is already implemented in the ALSA driver, but
            it doesn't work with ATI/AMD out-of-the-box.. either the ATI/AMD
            multichannel is completely different and needs its own handling, or
            there is some secret switch that makes the extra channels appear to the
            standard hdmi driver.


            Well, there is something missing on the 1st part as well (since the
            audio controller reports Stereo capability only), but it might be
            something as simple like some AMD specific switch to turn on
            multichannel support (since these last emails make it sound like AMD
            actually does follow the public Intel HD multichannel spec - or we are
            talking about different model series).

            The 2nd one I'm somewhat confused about. r600 already has support for
            mixing the audio into the HDMI stream, and multichannel audio shouldn't
            need any changes there (maybe he's talking about some newer models?).

            As for structures from industry standards, the EDID from VESA EDID, CEA
            EDID extension from EIA-CEA-861-D/E, and ELD from Intel HD audio spec
            (which are only needed for detection of supported audio formats of the
            receiver) are handled by common code in drm_edid.c:drm_edid_to_eld()
            (currently used on intel/nvidia), so no code needs to be added for those.

            Additionally, the video/audio infoframes from the HDMI specification are
            already implemented in r600_hdmi.c (and there is also a generic audio
            infoframe implementation in the ALSA HDA driver, which is used on
            intel/nvidia).

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            • #7
              Originally posted by geearf View Post
              I believe 2 years ago radeonhd hdmi audio driver went using the generic intel one.
              Unless I am mistaken, wouldn't that solve the alsa part?
              It doesn't matter what graphics driver you use, the audio device is always handled by the alsa driver.

              Originally posted by geearf View Post
              I am thinking of this patch: [PATCH] ALSA: hda - use generic hdmi parser for ATI R6xx codec, by Ansi.
              More info by him in case I'm missing something:
              As I said before, special handling is required on the alsa side.

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              • #8
                Alright, I thought that special handling was not special anymore but generic, but I guess I was wrong.

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                • #9
                  With all this AMD driver progress I am kinda doubting my NVIDIA 670 purchase. Is there anyone who games on Linux with AMD gfx who could weigh in? Mainly Skyrim and Torchlight II will be played. Is it worth thinking about changing cards to go with open source drivers?

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                  • #10
                    Originally posted by agd5f View Post
                    That requires changes to alsa hda driver. We are looking into it, but it's had a lower priority compared to other projects (UVD, DPM, etc.).
                    See http://zajec.net/blog/view/2013-mult...-amd-over-hdmi for further details. There may be some hope on the horizon- see http://mailman.alsa-project.org/pipe...il/060774.html and particularly http://mailman.alsa-project.org/pipe...il/060773.html

                    Also note that HDMI 1.4a/b only supports 4K resolution at 24/25/30 frames per second. This is fine for watching movies, but not for gaming. 4K resolution at 60 frames per second will require the yet to be released HDMI 2.0. Or you could just use a DisplayPort 1.2 connection - it supports [email protected] fps.

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