From mboxrd@z Thu Jan 1 00:00:00 1970 From: Liam Girdwood Subject: Re: ALSA concurrent use case for 5.1 LPCM on HDMI. Date: Thu, 26 Jul 2012 00:07:01 +0100 Message-ID: <1343257621.16982.9.camel@odin> References: <16e078f384eda9134af4b78dec4ec090.squirrel@www.codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from na3sys009aog112.obsmtp.com (na3sys009aog112.obsmtp.com [74.125.149.207]) by alsa0.perex.cz (Postfix) with ESMTP id A489D265B47 for ; Thu, 26 Jul 2012 01:07:03 +0200 (CEST) Received: by weyr1 with SMTP id r1so1030369wey.29 for ; Wed, 25 Jul 2012 16:07:03 -0700 (PDT) In-Reply-To: <16e078f384eda9134af4b78dec4ec090.squirrel@www.codeaurora.org> 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: gsantosh@codeaurora.org Cc: tiwai@suse.de, alsa-devel@alsa-project.org List-Id: alsa-devel@alsa-project.org On Wed, 2012-07-25 at 01:37 -0700, gsantosh@codeaurora.org wrote: > Hi All, > > I have following use case I am facing an issue with the ALSA framework, > > Consider a use case > > 1) System tone or any stream running on Front End 0 with stereo channel > configuration On Back End 0(HDMI) > 2) Start a local file playback for 5.1 LPCM on Front End 1 with 5.1 > channel configuration On Back End 0(HDMI) > > Here FE0 and FE1 is routed to same BE0. > > When step 2 is done I see following behavior of ALSA which is not correct. > Framework will check that the BE0 is running with FE0 routed and running, > Framework will not trigger the fixup and hw_params callback to re > configure the session for FE1 with 5.1 channel. > > With this effect we are playing the FE1 session with stereo instead of 5.1 > channel configuration, how to rectify this issue? > Hmm, the fixup code will currently only run when the BE0 is initially configured via hw_params(). The problem here is that if we fixup and reconfigure BE0 (via hw_params()) after it is running then this will likely cause undesired audio artifacts on BE0 (since in this case it's already playing stereo and we want to change to 6 channel). We have a similar situation with OMAP where we support many channels (2 - 6) on one McBSP BE DAI. We always configure the BE McBSP in 6 channel mode and that allows us to open any FE with 2...6 channels (without a fixup and restart of the McBSP port). Regards Liam > Regards, > Santosh M G. > > > >