From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pierre-Louis Bossart Subject: Re: ASoC: no-pcm (backend) error propagation Date: Wed, 27 Feb 2013 09:43:52 -0600 Message-ID: <512E29B8.8050708@linux.intel.com> References: <190351B32828744FBA3BD9565204D27B01CA3AF2@NA-MBX-03.mgc.mentorg.com> <1361953433.28121.33.camel@vega> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: Received: from mga03.intel.com (mga03.intel.com [143.182.124.21]) by alsa0.perex.cz (Postfix) with ESMTP id 3C4532650DB for ; Wed, 27 Feb 2013 16:44:05 +0100 (CET) In-Reply-To: <1361953433.28121.33.camel@vega> 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: Liam Girdwood Cc: "alsa-devel@alsa-project.org" , Mark Brown , Liam Girdwood , "Frkuska, Joshua" List-Id: alsa-devel@alsa-project.org > It was originally intended that any underrun / overrun issues in a BE > DAI would be handled internally by the audio DSP (and this worked well > with the OMAP4 ABE). However, it is probably a good a idea to have a > better mechanism for reporting BE xrun issues up the stack to the host > CPU side too. > > Currently the FE PCM xrun mechanism and FE pointer() callback could be > used by the host to get the size of any FE:BE underrun/overrun. This > isn't ideal and wont work when there can be multiple BEs for a FE. > > It looks like some new code is required here to get this working > correctly for BEs. My view is that that underruns at the DSP level are fatal anyway, and that they a) should be avoided with proper real-time designs and b) they should be logged as error conditions to debug should they occur, not be tied to a FE. It would be really complicated to add code to back-propagate the errors, and if you have mixing/routing what individual FEs would do when this is a system error really. -Pierre