From mboxrd@z Thu Jan 1 00:00:00 1970 From: Timur Tabi Subject: Re: Will ALSA ever call _prepare or _hw_params while it's playing? Date: Wed, 21 May 2008 10:56:50 -0500 Message-ID: <48344642.3050707@freescale.com> References: <4834438A.4060702@freescale.com> <48344582.8020601@alsa-project.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <48344582.8020601@alsa-project.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: Clemens Ladisch Cc: ALSA development List-Id: alsa-devel@alsa-project.org Clemens Ladisch wrote: > Timur Tabi wrote: >> I have an ASoC driver with a _hw_params, _prepare, and _trigger functions. I've >> recently discovered that I need to keep one of my devices disabled until >> playback starts. >> >> So I would like to know if ALSA will ever call _hw_params, _prepare, or _trigger >> if playback or capture is currently in process, or will ALSA first call the >> _trigger to stop/pause the driver. > > While a stream is running (after trigger with START), ALSA will only > call the pointer or the trigger (STOP/PAUSE/SUSPEND) callbacks. That's good. > Different streams are not synchronized in any way. (This also applies to > the playback/capture streams of one card.) Ah, I hadn't thought about that. If I'm doing simultaneous capture and playback through the same device, then I can't guarantee that it's disabled. Argh. Thanks. -- Timur Tabi Linux kernel developer at Freescale