From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eliot Blennerhassett Subject: Understanding SND_PCM_INFO_ [BATCH, BLOCK_TRANSFER, DOUBLE] Date: Wed, 17 Feb 2010 20:35:36 +1300 Message-ID: <4B7B9C48.5070608@audioscience.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from smtp5.clear.net.nz (smtp5.clear.net.nz [203.97.33.68]) by alsa0.perex.cz (Postfix) with ESMTP id 924DC103847 for ; Wed, 17 Feb 2010 08:36:29 +0100 (CET) Received: from [192.168.1.6] (121-72-250-62.cable.telstraclear.net [121.72.250.62]) by smtp5.clear.net.nz (CLEAR Net Mail) with ESMTP id <0KXZ0028U6GPWN20@smtp5.clear.net.nz> for alsa-devel@alsa-project.org; Wed, 17 Feb 2010 20:36:26 +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 I've been looking at these info flags, and whether they cause the driver to be accessed any differently by the upper layers. So far I can find hardly any examples where they are used in any significant way - what am I missing if anything? SND_/SNDRV_ _PCM_INFO_BATCH double buffering skips the check enabled by XRUN_DEBUG_JIFFIESCHECK alsa-lib returns it in snd_pcm_hw_params_is_batch() _PCM_INFO_BLOCK_TRANSFER /* hardware transfer block of samples */ translated by pcm_oss.c into ~DSP_CAP_REALTIME lib: snd_pcm_hw_params_is_block_transfer() _PCM_INFO_DOUBLE /* double buffering needed for PCM start/stop */ snd_pcm_hw_params_is_double() I don't see any of these functions called by aplay... -- Eliot