From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Ujfalusi Subject: Re: [PATCH] ASoC: OMAP: Add checking to detect bufferless pcms Date: Wed, 22 Apr 2009 12:42:46 +0300 Message-ID: <200904221242.46541.peter.ujfalusi@nokia.com> References: <49EE7962.6080008@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: Received: from mgw-mx06.nokia.com (smtp.nokia.com [192.100.122.233]) by alsa0.perex.cz (Postfix) with ESMTP id 862742465C for ; Wed, 22 Apr 2009 11:43:14 +0200 (CEST) In-Reply-To: Content-Disposition: inline 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: ext Jarkko Nikula Cc: "kyungmin.park@samsung.com" , "alsa-devel@alsa-project.org" , "broonie@opensource.wolfsonmicro.com" , Joonyoung Shim , "bhmin@samsung.com" List-Id: alsa-devel@alsa-project.org On Wednesday 22 April 2009 11:30:32 ext Jarkko Nikula wrote: > On Wed, Apr 22, 2009 at 4:56 AM, Joonyoung Shim > > wrote: Add > checking in hw_params and prepare to detect bufferless pcms(i.e. BT <--> > codec). > > I see exactly similar lines in s3c24xx-pcm.c but don't point now the use > case where this is used and I don't have idea what is this all about. > > Is this something where DAI driver or another end of connection is used to > provide clocking and the whole setup is then controlled with ALSA PCM API? > Somehow I have the feeling that would there be a better way to achieve it > than with dummy bufferless transfer? In the twl codec, the BT interface does not have dedicated clock line, but = it = is (re)using the clock lines for the voice PCM interface. So in order to ge= t = BT data going between the BT and the codec, the voice PCM interface has to = generate the clocks. But I think this could be done even without the need for the alsa PCM = interface, probably well placed DAPM switches would also can take care of = this? > > -- > Jarkko -- = P=E9ter