From mboxrd@z Thu Jan 1 00:00:00 1970 From: Timur Tabi Subject: Re: hw_params function and OSS emulation Date: Wed, 22 Aug 2007 17:08:18 -0500 Message-ID: <46CCB3D2.7060908@freescale.com> References: <46CB2BB4.9060808@freescale.com> <46CC480F.7090604@freescale.com> <46CCA5E1.5050704@freescale.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from az33egw01.freescale.net (az33egw01.freescale.net [192.88.158.102]) by alsa0.perex.cz (Postfix) with ESMTP id 01DC9103804 for ; Thu, 23 Aug 2007 00:08:22 +0200 (CEST) In-Reply-To: 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: Takashi Iwai Cc: alsa-devel@alsa-project.org, Trent Piepho List-Id: alsa-devel@alsa-project.org Takashi Iwai wrote: > The purpose of prepare callback is to make the PCM stream ready to > start. (The trigger callbacks are supposed to be just triggering, not > preparing the stream.) > Usually, once after the PCM is triggered, the registers are no > longer as same as the beginning. If you want to stop and restart the > stream, you'll very likely to reset the registers again. That's why > prepare is called again. (Or, your driver is always go-or-die? :) I thought you meant that the .prepare() function can be called multiple times *in a row*, like .hw_params() is. But I guess that's not what you meant. -- Timur Tabi Linux Kernel Developer @ Freescale