From mboxrd@z Thu Jan 1 00:00:00 1970 From: Clemens Ladisch Subject: Re: maximum tolerable sampling frequency difference for a driver Date: Wed, 12 Nov 2008 16:35:44 +0100 Message-ID: <491AF7D0.40806@ladisch.de> References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from out5.smtp.messagingengine.com (out5.smtp.messagingengine.com [66.111.4.29]) by alsa0.perex.cz (Postfix) with ESMTP id A8D1F24499 for ; Wed, 12 Nov 2008 16:35:34 +0100 (CET) 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: chri Cc: alsa-devel@alsa-project.org List-Id: alsa-devel@alsa-project.org chri wrote: > Let's say that the driver cannot set the exact sampling frequency > asked via hwparms ... This never happens. The driver tells the ALSA framework what frequencies it supports, either by setting individual bits in the .rates field, or by installing a constraint by calling snd_pcm_hw_constraint_list() or some other of the constraint functions when the device is opened. ALSA then makes sure that the driver always gets values in hw_params that meet these constraints. When an application requests a frequency that is not supported by the device, it is the application that must decide whether the actual frequency is acceptable. HTH Clemens