From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Brown Subject: Re: [PATCH 3/3] ASoC: omap-mcbsp: Add period size protection mode Date: Tue, 20 Mar 2012 16:01:56 +0000 Message-ID: <20120320160154.GI3445@opensource.wolfsonmicro.com> References: <1332242021-7494-1-git-send-email-peter.ujfalusi@ti.com> <1332242021-7494-4-git-send-email-peter.ujfalusi@ti.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============7752182951218494748==" Return-path: Received: from opensource.wolfsonmicro.com (opensource.wolfsonmicro.com [80.75.67.52]) by alsa0.perex.cz (Postfix) with ESMTP id 2A5BB10430E for ; Tue, 20 Mar 2012 17:01:59 +0100 (CET) In-Reply-To: <1332242021-7494-4-git-send-email-peter.ujfalusi@ti.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: alsa-devel-bounces@alsa-project.org Errors-To: alsa-devel-bounces@alsa-project.org To: Peter Ujfalusi Cc: alsa-devel@alsa-project.org, Liam Girdwood , Jarkko Nikula , Grazvydas Ignotas List-Id: alsa-devel@alsa-project.org --===============7752182951218494748== Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="boAH8PqvUi1v1f55" Content-Disposition: inline --boAH8PqvUi1v1f55 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Tue, Mar 20, 2012 at 01:13:41PM +0200, Peter Ujfalusi wrote: > Certain application can experience underrun right after the playback start. > This is caused by the McBSP FIFO/sDMA integration: > The sDMA will push samples to the FIFO till it has threshold amount of free > slots available in the FIFO. If the application picks period size which is > smaller than the FIFO size, and it did not prepared multiple periods, or > it did not set the start_threshold for the stream to cover the FIFO size > the hw pointer will move forward, which is causing the underrun. Acked-by: Mark Brown though this should probably have the note about working around broken applications from the cover letter in the changelog as with the changelog alone it's really not apparent why we're doing this here as a driver specific thing. --boAH8PqvUi1v1f55 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) iQIcBAEBAgAGBQJPaKnqAAoJEBus8iNuMP3dA04P/2V37WCbeqUQhmQRjNi2zvJv nzXMeLZ/QVbtiuz2AsQsL0XE1LAr17L5pVEbNXYQOLExJ+0g9ipsQ4kyiGVZTaYN hiidWpdrly9P+mctdBiZ+L3l4jswxp9YR+8QYOXIGF3vW1ICSSMMZsv2tX0hpQbh HTYyKCgZgToilL4rnDikOqwHa6b2jM2JDuM9uMt431mhteP1LyHA+qac51oC7eeW ZsgIBFXLMQlclx3YQ0BnCCt1egRbd0rxfFBIEGlIxSuEh1zcHofEcwK6xTZ1whWy kgMvE93dyGp0rEvhSII9iImJqXUyXHM8nibxTaJFSvA7RQqBIu063JSGmdlZXQzY xbNfzVuMHsBfYyytO1NGJZiAV6RxDYb5pIs8yUen2mt9MwwX8ts2JkEuCDBGHqo2 NSQSy4+h1s3GImodoIP9q9vZNKss3m66xQ/telpCLov7Uu7JghhB38qWr1N7Aqg6 pE8ATgHjro0hQstPDEKl2NVqRPPMAQRF1sq123jWvC2OxUzWYjzYDo0qw5+eyfia Y8hsjF7oy53aGN2RGN+ImpKFiqlRRD4kolvlM094nm7dQuvILO2dgT7hleyx4FcC ziHc8p/6PjBDmPVm0tDn+4lVuwRi+zVpqPh6QrbE1vDAMB+14eYBb89j3HFK/Jj6 PV/cUhYT91IRs59LIS+x =iN6S -----END PGP SIGNATURE----- --boAH8PqvUi1v1f55-- --===============7752182951218494748== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline --===============7752182951218494748==--