From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lennart Poettering Subject: Re: safe support for rewind in ALSA Date: Wed, 17 Feb 2010 16:46:56 +0100 Message-ID: <20100217154656.GF6891@tango.0pointer.de> References: <4f3252891002081459q29f02414hf168a596ab641995@mail.gmail.com> <4f3252891002100519h132fddb8t1f2bc56e97bf5c40@mail.gmail.com> <4B72B665.3060903@ladisch.de> <4f3252891002102252vb6d7a94l76fb78e33da37775@mail.gmail.com> <4B73AFD5.4080205@ladisch.de> <4f3252891002141903q34144f58n60978e28e65640b4@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from tango.0pointer.de (tango.0pointer.de [85.214.72.216]) by alsa0.perex.cz (Postfix) with ESMTP id A58C7103871 for ; Wed, 17 Feb 2010 16:47:21 +0100 (CET) Content-Disposition: inline In-Reply-To: <4f3252891002141903q34144f58n60978e28e65640b4@mail.gmail.com> 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: Raymond Yau Cc: alsa-devel@alsa-project.org List-Id: alsa-devel@alsa-project.org On Mon, 15.02.10 11:03, Raymond Yau (superquad.vortex2@gmail.com) wrote: > For USB case , the driver cannot give accurate hw pointer position , hw > pointer increase in steps for the current implementation, (i.e. the graph is > a stepping fuction if you plot the position of hardware pointer against time > elasped ) . The granularity of write transfer blocks and of playback pointer updates is currently not quriable nor configurable in ALSA. We only have periods which tries to cover both in a way. For the use in PA it is really important to get better APIs for this. Ideally both for querying the latency and the transfer granularityand configuring it, but most importantly for querying it. This has been discussed before on this mailing list, btw. Lennart -- Lennart Poettering Red Hat, Inc. lennart [at] poettering [dot] net http://0pointer.net/lennart/ GnuPG 0x1A015CC4