From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pierre Ossman Subject: Re: radeon multi-channel lpcm Date: Wed, 5 Sep 2012 19:22:39 +0200 Message-ID: <20120905192239.6a212683@mjolnir.ossman.eu> References: <20120831223447.065fcb62@mjolnir.ossman.eu> <20120905181923.2e330a63@mjolnir.ossman.eu> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============8753699189189154075==" Return-path: Received: from smtp-relay.ossman.eu (saehrimnir.ossman.eu [193.12.253.10]) by alsa0.perex.cz (Postfix) with ESMTP id D7E9526007E for ; Wed, 5 Sep 2012 19:22:44 +0200 (CEST) In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: alsa-devel-bounces@alsa-project.org To: Takashi Iwai Cc: alsa-devel@alsa-project.org List-Id: alsa-devel@alsa-project.org This is a MIME-formatted message. If you see this text it means that your E-mail software does not support MIME-formatted messages. --===============8753699189189154075== Content-Type: multipart/signed; micalg=PGP-SHA256; protocol="application/pgp-signature"; boundary="=_freyr.ossman.eu-26335-1346865763-0001-2" This is a MIME-formatted message. If you see this text it means that your E-mail software does not support MIME-formatted messages. --=_freyr.ossman.eu-26335-1346865763-0001-2 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Wed, 05 Sep 2012 18:39:01 +0200 Takashi Iwai wrote: > At Wed, 5 Sep 2012 18:19:23 +0200, > Pierre Ossman wrote: > >=20 > > Noone with any insight? I'm ready to do some leg work, but I couldn't > > find anything in either the HDA specification, or the AMD > > documentation. :/ >=20 > Well, HD-audio HDMI codec driver just extracts the available channel > setup from the given ELD, and the ELD data is sent from the graphics > driver. So, if anything missing in ELD, it's supposed to be in the > graphics driver side. In other words, if ELD doesn't give 6 channels, > HD-audio codec won't follow that channel setup, too. >=20 I see. I got a bit confused by this code though: /* Restrict capabilities by ELD if this isn't disabled */ if (!static_hdmi_pcm && eld->eld_valid) { Which made me think that the ELD was just used to make sure you didn't send something the other end couldn't handle. IOW, eld_valid =3D=3D false would give you all features the hw was capable off. Some follow up questions, to confirm I haven't confused things: - The ELD really needs to go into the hardware, not just end up in the hands of the audio driver? IOW, we cannot override this? - The HDA interface only defines reading the ELD, so writing it would have to be done by the graphics driver using some GPU interface? If so, I need to poke the AMD guys as I couldn't find any information in the public documentation about writing the ELD. Thanks --=20 -- Pierre Ossman WARNING: This correspondence is being monitored by FRA, a Swedish intelligence agency. Make sure your server uses encryption for SMTP traffic and consider using PGP for end-to-end encryption. --=_freyr.ossman.eu-26335-1346865763-0001-2 Content-Type: application/pgp-signature; name="signature.asc" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.18 (GNU/Linux) iF4EAREIAAYFAlBHimIACgkQopDLsoqlmEK0rQEAyQaf87b4u8DDp9IZRFPmKtUZ UuplEHWK5d/0b7WKaoMA/1E3sEZTnXMfnjxv7MbiToB3X3vbVAq3XWp1R3peCTRh =XPno -----END PGP SIGNATURE----- --=_freyr.ossman.eu-26335-1346865763-0001-2-- --===============8753699189189154075== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline --===============8753699189189154075==--