From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753806Ab3GOR5v (ORCPT ); Mon, 15 Jul 2013 13:57:51 -0400 Received: from cassiel.sirena.org.uk ([80.68.93.111]:56894 "EHLO cassiel.sirena.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752910Ab3GOR5t (ORCPT ); Mon, 15 Jul 2013 13:57:49 -0400 Date: Mon, 15 Jul 2013 18:57:26 +0100 From: Mark Brown To: Vinod Koul Cc: Lars-Peter Clausen , Liam Girdwood , alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org Message-ID: <20130715175726.GA11538@sirena.org.uk> References: <1373906531-6938-1-git-send-email-lars@metafoo.de> <20130715172643.GZ11538@sirena.org.uk> <20130715165721.GV16653@intel.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="LG5jgFgJbJFFiAfj" Content-Disposition: inline In-Reply-To: <20130715165721.GV16653@intel.com> X-Cookie: Advancement in position. User-Agent: Mutt/1.5.21 (2010-09-15) X-SA-Exim-Connect-IP: 94.175.92.69 X-SA-Exim-Mail-From: broonie@sirena.org.uk Subject: Re: [RFC 1/2] ASoC: dmaengine-pcm: Add support for querying DMA capabilities X-SA-Exim-Version: 4.2.1 (built Mon, 26 Dec 2011 16:57:07 +0000) X-SA-Exim-Scanned: Yes (on cassiel.sirena.org.uk) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --LG5jgFgJbJFFiAfj Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Mon, Jul 15, 2013 at 10:27:21PM +0530, Vinod Koul wrote: > On Mon, Jul 15, 2013 at 06:26:43PM +0100, Mark Brown wrote: > > On Mon, Jul 15, 2013 at 06:42:10PM +0200, Lars-Peter Clausen wrote: > > > + hw.period_bytes_min = 16; > > > + hw.period_bytes_max = dma_caps.max_sg_len; > > We can't read the minimum period size from dmaengine? Seems like > > something might have a restriction other than 16 bytes here. > max would be how many list items the engine supports so queried therotical min > would be 1 byte, not sure how 16 bytes is assumed above but my guess is that if > engine is able to push min burst lengths which would be 1 and give you > interrupt. But seriously, that would not be practical. So this should be a > realistic limit which system can cope with. Right, we probably want to set an artificial floor here but it still seems like we should be checking that the device actually supports this. If the hardware can only support 64 bytes then the above code won't work properly. --LG5jgFgJbJFFiAfj Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.20 (GNU/Linux) iQIcBAEBAgAGBQJR5DgDAAoJELSic+t+oim9OuUP/ArcS/0NdnJ7kanUhVn7Ax0/ /caC6QIKNerQWOD48ly7PxKtsG9EBPCj/UEbQkAi9GpcsIaCOvmV+n0tFhpTzgPO OoJAzgxFMYsMCXjzQnyFZpHbsniz+Pkliz8cCX5xgkmXac9kYGd8DYshkQO9Ws5+ Z9FAkYt9VlE14e8q9jVd3tMNilkCWbo1nE3LhZiuQ9OoezZHWaZtCCBvx8/6VqwE bLnDLfoP96kVxFq7Fb7CD/rNyPk3NynrFOiAdgCuwJDGCSR6d6KxJnKdUucD/xoE laj3cVDMRPUGJpeSI/1d27SHFiDZJwPKOmaKs2k62qaNavN8vgAQnnO6oDxIkP9T duN/+QQrdjNhX6zjTFXbIgUxtKZeF4BHN4W6I7nJUn/gPYOPZWt9vXju41wXdWQF 6WwJaBlXVg+aKGWFHZQidZBpeOkgVTyNZGPF7wS7cdhFxMUxZp0A6B9ondOS5MRz fPlczj7vd2REJ5BDf+QfZXScSWn4EJQWXwqUHI5flXhlMHyJ9v/k7RSIgJI3SX95 zkTElOOU2pYOdnQlZgnElkUJUt5D6P/IEmYlgkMtPOlmIIHv1OU5IRTght7pcdjc gWB0aKPjbZrurThLfqLbeddDtlq7z9Qe5vxEM/e5FXoBgCzxJLUNn2Q96+GrWY8C fAhD9sB9Of3VeocJoedn =h2Cj -----END PGP SIGNATURE----- --LG5jgFgJbJFFiAfj--