From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eliot Blennerhassett Subject: driver silence callback Date: Thu, 24 Mar 2011 13:32:13 +1300 Message-ID: <4D8A910D.6030604@audioscience.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from smtp3.clear.net.nz (smtp3.clear.net.nz [203.97.33.64]) by alsa0.perex.cz (Postfix) with ESMTP id 9787D103948 for ; Thu, 24 Mar 2011 01:32:22 +0100 (CET) Received: from [192.168.36.2] (121-72-250-62.cable.telstraclear.net [121.72.250.62]) by smtp3.clear.net.nz (CLEAR Net Mail) with ESMTP id <0LIJ00BX5DHPJF50@smtp3.clear.net.nz> for alsa-devel@alsa-project.org; Thu, 24 Mar 2011 13:32:14 +1300 (NZDT) 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: alsa-devel@alsa-project.org List-Id: alsa-devel@alsa-project.org Greetings, Is the driver's silence callback meant to be able to *overwrite* some part of the audio buffer that has already been written e.g. via the playback *copy* callback? In the case of my (older) hardware, once audio has been written via the copy callback, it is gone (into a fifo), there is no way to overwrite with silence. The asihpi silence call back will _append_ a period of silence to the already written audio queue. I'm wondering if this is wrong? Perhaps I should not have a silence callback at all? I'm looking at the case in pcm_lib.c snd_pcm_playback_silence() where "when runtime->silence_size >= runtime->boundary - fill processed area with silence immediately" My reference for silence callback. http://www.alsa-project.org/~tiwai/writing-an-alsa-driver/ch11s02.html regards Eliot