From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Brown Subject: Re: [RFC PATCH 1/4] alsa: make hw_params negotiation infrastructure 'bclk_ratio aware' Date: Tue, 12 Mar 2019 15:03:00 +0000 Message-ID: <20190312150300.GE6983@sirena.org.uk> References: <20190304165955.21696-1-TheSven73@gmail.com> <20190305044232.GA15636@workstation> <20190308041056.GA1172@workstation> <20190308125916.2cgiqclp6jmlfbim@shell.armlinux.org.uk> <20190308172235.GA31189@sirena.org.uk> <25dec9c5-af5c-bc54-89dd-2abdeffa9f82@perex.cz> <20190311081546.GA8324@workstation> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============0070201644819477833==" Return-path: Received: from heliosphere.sirena.org.uk (heliosphere.sirena.org.uk [IPv6:2a01:7e01::f03c:91ff:fed4:a3b6]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by alsa1.perex.cz (Postfix) with ESMTPS id 221E4F806F5 for ; Tue, 12 Mar 2019 16:03:04 +0100 (CET) In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: "Alsa-devel" To: Jaroslav Kysela Cc: Sven Van Asbroeck , alsa-devel@alsa-project.org, Russell King - ARM Linux admin List-Id: alsa-devel@alsa-project.org --===============0070201644819477833== Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="6sX45UoQRIJXqkqR" Content-Disposition: inline --6sX45UoQRIJXqkqR Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Mon, Mar 11, 2019 at 04:43:39PM +0100, Jaroslav Kysela wrote: > I would not use any of the "user space" ioctl API to represent the > hardware bclk requirements. The applications should know just the DMA > memory layout. > Also, think about the multiple simultaneous paths for the audio output > in the sound controller (so one DMA from the user space to the > controller, but the controller can do multiple simultaneous outputs > using different clocks combining different wire buses or so). Yes, it's > the corner case, but it's another reason to have the bclk code totally > separated from the user space ALSA's PCM API. There's also a range of devices that either don't have visible buses at all due to integration or which are on buses that look nothing like the I2S/DSP mode style of bus, rendering the parameters meaningless. --6sX45UoQRIJXqkqR Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAlyHyiMACgkQJNaLcl1U h9C1lgf/bPRMpiIC4rCVBkCQlA4Gm6guRqBKxzYVzLfKa8OqnCn/oJu0KFI8PWbw oidJA6/Iv4pYKxL3T3+jWKKSV6WKLkN0WbysvX6X1SPg7jaKnkR29AxXcjyzBvUK 2+4hqXFpPscYu3oz1yLa7Ezcbc75VNaIY1PwuXKTudwzFikf/I7LEr1MzD3JetqG sjNBBZSgW7Bc3P3j9LyJuRtodvYNhI04X7czV/cdLdOgWBeRWt7vd+z2Q9Q+5i3w 8lo5DnPPlAqC+E+khofGLfgsB3bRV+5vL3ZKDWEZ3dQ+1bBxWCwl655kIBjdtH/O y3TJFcGUTdzee6CJlVIivcvQuIF2Ug== =GxPZ -----END PGP SIGNATURE----- --6sX45UoQRIJXqkqR-- --===============0070201644819477833== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline --===============0070201644819477833==--