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AMD Displays Graphics Software Linux

AMD Intentionally Added Artificial Limitations To Their HDMI Adapters 256

An anonymous reader writes "NVIDIA was caught removing features from their Linux driver and days later Linux developers have caught and confirmed AMD imposing artificial limitations on their graphics cards in the DVI-to-HDMI adapters that their driver will support. Over years AMD has quietly been adding an extra EEPROM chip to their DVI-to-HDMI adapters that are bundled with Radeon HD graphics cards. Only when these identified adapters are detected via checks in their Windows and Linux Catalyst driver is HDMI audio enabled. If using a third-party DVI-to-HDMI adapter, HDMI audio support is disabled by the Catalyst driver. Open-source Linux developers have found this to be a self-imposed limitation and that the open-source AMD Linux driver will work fine with any DVI-to-HDMI adapter."
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AMD Intentionally Added Artificial Limitations To Their HDMI Adapters

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  • Re:Why do this? (Score:4, Informative)

    by h4rr4r ( 612664 ) on Tuesday October 08, 2013 @09:50AM (#45069359)

    Because carriers pay extra for that or will not carry a phone without it.

  • Re:Why do this? (Score:5, Informative)

    by marcomarrero ( 521557 ) on Tuesday October 08, 2013 @10:07AM (#45069547)
    I think you're right, and I also think sending audio through DVI is a ugly non-standard proprietary hack, so it's logical it only works with their adapters.
  • Re:Why? (Score:5, Informative)

    by Sarten-X ( 1102295 ) on Tuesday October 08, 2013 @10:09AM (#45069573) Homepage

    Because DVI isn't supposed to carry audio.

    I suspect there's a licensing agreement somewhere saying they must conform to the DVI spec, including its lack of audio support, but if they count the HDMI adapter as a part of the whole system, they're just using a DVI-like connector in the middle of an HDMI system.

    Another cause could be avoiding liability. If they send out audio by default and it breaks some other device, they're at fault. If the other device asked for it (by the presence of the special chip), it should be able to handle it just fine.

    As yet another possible reason, the audio-over-DVI system could have been designed as a feature, that AMD simply abandoned. Since they've done the work implementing it in their chips and adapters, it costs almost nothing more for them to keep using it, probably even costing less than it would to support separate product lines with and without the capability. However, they may not want to run the extra expense of publishing and supporting yet another standard, when HDMI is already showing wide adoption as the next standard for everything.

  • Re:Why do this? (Score:5, Informative)

    by Baloroth ( 2370816 ) on Tuesday October 08, 2013 @10:17AM (#45069683)

    My guess is because the DVI standard doesn't actually have an audio transport channel, so they only switch it on when a DVI connection that they recognize as a DVI-to-HDMI adaptor is attached. They can only do that when one of their adapters is attached. Otherwise, they see a DVI device so they output a proper DVI signal. It's sticking to the DVI specifications very precisely (perhaps a bit too precisely).

    Of course, I don't know enough about the specs to say for sure if that is why, or if there would be a better way (I strongly suspect there is, but am not sure).

  • by Rhipf ( 525263 ) on Tuesday October 08, 2013 @10:43AM (#45069987)

    I guess I'm missing something here. What is the big deal if HDMI audio is turned off when using DVI since DVI doesn't carry an audio signal anyway?

  • Re: Why? (Score:5, Informative)

    by Anonymous Coward on Tuesday October 08, 2013 @11:43AM (#45070865)

    It shouldn't, since it's ridiculously easy to work around.

    Don't install the Realtek drivers.

    Remember, Microsoft provides the Stereo Mix utility of the audio subsystem, and in order to pass WHQL certification, the drivers have to meet the minimum spec defined by Microsoft. So Realtek may have agreements with whoever-it-is (and it's not Microsoft) to remove the Stereo Mix from their drivers, but the WHQL certification process requires that it be enabled.

    So don't install the drivers that have Stereo Mix disabled, and let Windows Update install the WHQL certified ones instead. I have Realtek audio in my system, and the Stereo Mix path works fine. It can take a bit of work to find how to activate it in Windows 7, but it's there, and it works.

  • Re:Why do this? (Score:2, Informative)

    by wagnerrp ( 1305589 ) on Tuesday October 08, 2013 @11:47AM (#45070937)
    The ROM tells the TMDS transmitters to use HDMI signalling on the DVI port, which sends packets over three data channels and allows audio, rather than DVI signalling, which sends subpixel data over three color channels and does not allow audio.

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