From mboxrd@z Thu Jan 1 00:00:00 1970 From: Takashi Iwai Subject: Re: [PATCH] ALSA: pcm: add a documentation for tracepoints Date: Mon, 26 Jun 2017 15:41:38 +0200 Message-ID: References: <20170626132721.5509-1-o-takashi@sakamocchi.jp> Mime-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mx1.suse.de (mx2.suse.de [195.135.220.15]) by alsa0.perex.cz (Postfix) with ESMTP id A4D99266A0C for ; Mon, 26 Jun 2017 15:41:40 +0200 (CEST) In-Reply-To: <20170626132721.5509-1-o-takashi@sakamocchi.jp> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: alsa-devel-bounces@alsa-project.org To: Takashi Sakamoto Cc: alsa-devel@alsa-project.org List-Id: alsa-devel@alsa-project.org On Mon, 26 Jun 2017 15:27:21 +0200, Takashi Sakamoto wrote: > > +In a design of ALSA PCM core, data transmission is abstracted as PCM substream. > +Applications manage PCM substream to maintain data transmission for PCM frames. > +Before stating the data transmission, applications need to configure PCM starting > +This structure includes several types of parameters. Applications set preferable > +value to these parameters, then execute ioctl(2) with SNDRV_PCM_IOCTL_HW_REFINE > +or SNDRV_PCM_IOCTL_HW_PARAMS. The former is used just for querying available > +set of parameters. REFINE isn't only for querying but may also refine, i.e. partially change the parameters. > +Pamraeters in the buffer are changed according to Parameters thanks, Takashi