Date: Thu, 03 Jan 2008 12:49:05 -0500 From: Chuck Robey <chuckr@chuckr.org> To: freebsd-multimedia@freebsd.org Subject: the snd_hda stuff Message-ID: <477D2011.9010407@chuckr.org>
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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 I've now done a pretty fair amount of reading on this, and I have some questions, and some comments, so I thought, if you;'d care to, we could have a little discussion about the snd_hda driver. I've asked two questions, too, but go ahead and adress anything that you'd like, I am looking to provoke some discussion about this oddball architecture. My own setup is what I've got at home: an ASUS Striker Extreme motherboard. The board has a Nvidia 680i chipset, and an Analog Devices AD1988B codec. I haven't been able to find any specifications at all about what the 680i does, excepting a scatterming of reviews which all say that it supports the Intel High Definition Audio (HDA) Azalia sound architecture. For the HDA arch, Intel publishes a really jnice spec on that, and a spec for their ICH7 chipset, which, while it tells me nothing about what the Nvidia 680i has, at least tells me in greater detail how the Azalia architecture is supposed to work. Reading the datasheet on the Analog Devices AD1988B tells me (if I trust the advertising wording in that datasheet) that the AD1988B is supposed to handle Dolby's AC3 and the DTS 5.1, 6.1, and 7.1 encoding, so I also found the specs on those encodings, which happen to exist on the web also. So, my first question is, would it be legal to stick these great docs on our website for folks to download? Or, if that wasn't legal, maybe if I supplied the URL's, could we maybe show hotlinks for them? I know nothing about the legalities of that, I need advice on what's legal, but I'd sure like to make what I've gathered available to everyone. OK, my driver question: first, you need to understand, this chip doesn't look like any previous audio design, because it's setup up with a large number of internal muxes, and the entire internal architecture is mutable. I guess that's why I think that the task of writing a driver for this device, well, it must have been a gigantic problem. Even trying to figure the device or driver architecture is open to question, not merely to supply stereo, like earlier designs needed to do. I'm hugely impressed. Because the chip design is so very configurable, the man page is particularly badly needed, but unfortunately, it gives me very little info. Is there maybe some doc I haven't yet found, that might help me understand how I could use the snd_hda driver? How to configure it, what the inputs and outputs are? I can't make use of it as it stands now. I would be willing to help on the driver, if it needs more, so if there's any more documents on either how it works, or maybe how folks want it to work? Please, help me on this. For a device that's so different, the need for documentation is badly needed. Is there maybe some wiki dealing with the hda driver? Such a huge task shouldn't sit unused because it's not documented, should it? -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.4 (FreeBSD) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFHfSARz62J6PPcoOkRAtN4AKCZ9fOwCAD21P2bBlOV1nC+PAEuuACfa+gg /doZrtGTB/O01U/7AVjEj3U= =idFD -----END PGP SIGNATURE-----
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