From mboxrd@z Thu Jan 1 00:00:00 1970 From: Clemens Ladisch Subject: Re: ASoC:Question on strict sequence followed for trigger Date: Thu, 29 Mar 2012 08:49:37 +0200 Message-ID: <4F740601.8080907@ladisch.de> References: <1ea6fbaaca7ffeaa7b7325f18fe4e959.squirrel@www.codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from out1-smtp.messagingengine.com (out1-smtp.messagingengine.com [66.111.4.25]) by alsa0.perex.cz (Postfix) with ESMTP id BF97E104353 for ; Thu, 29 Mar 2012 08:46:24 +0200 (CEST) Received: from compute1.internal (compute1.nyi.mail.srv.osa [10.202.2.41]) by gateway1.nyi.mail.srv.osa (Postfix) with ESMTP id 3E29F20BDB for ; Thu, 29 Mar 2012 02:46:18 -0400 (EDT) In-Reply-To: <1ea6fbaaca7ffeaa7b7325f18fe4e959.squirrel@www.codeaurora.org> 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: gsantosh@codeaurora.org Cc: alsa-devel@alsa-project.org List-Id: alsa-devel@alsa-project.org gsantosh@codeaurora.org wrote: > I see there is a strict sequence followed for trigger callback to codec > dai, platform dai and cpu dai. > In the below function of soc-core . > int soc_pcm_trigger(struct snd_pcm_substream *substream, int cmd); > > In some scenarios we may require the sequence to be the other case to make > sure the underlying DSP / codec is configured and triggered properly. The trigger callback should do nothing but actually start the stream. (In the ideal case, this would be setting one bit in a register of the DMA controller.) Any configuration should be done in hw_params. Regards, Clemens