From mboxrd@z Thu Jan 1 00:00:00 1970 From: Takashi Iwai Subject: Re: RFC: Add support for monotonic clock for 2.6 Date: Wed, 07 Mar 2007 23:48:39 +0100 Message-ID: References: <45EF3DB5.3090008@superbug.co.uk> 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 (mail.suse.de [195.135.220.2]) by alsa0.perex.cz (Postfix) with ESMTP id B04BA2432F for ; Wed, 7 Mar 2007 23:48:39 +0100 (CET) In-Reply-To: <45EF3DB5.3090008@superbug.co.uk> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: alsa-devel-bounces@lists.sourceforge.net Errors-To: alsa-devel-bounces@lists.sourceforge.net To: James Courtier-Dutton Cc: ALSA development , Jaroslav Kysela List-Id: alsa-devel@alsa-project.org At Wed, 07 Mar 2007 22:33:25 +0000, James Courtier-Dutton wrote: > > Takashi Iwai wrote: > > At Tue, 27 Feb 2007 15:52:41 +0100 (CET), > > Jaroslav Kysela wrote: > >> Hi, > >> > >> in 2.6 kernels, we can use ktime_get_ts() function to get > >> monotonic time which can be used for PCM timestamps. I would propose to > >> reuse the SNDRV_PCM_IOCTL_TSTAMP ioctl to enable using of monotonic clock. > >> The "enable" (int) argument might mean: > >> > >> 0: standard clock - getnstimeofday() > >> 1: standard clock - getnstimeofday() - for "compatibility" > >> 2: monotonic clock - ktime_get_ts() > > > > Good to add a new feature... but is there any user of this PCM > > timestamp so far? I see some good purposes but rarely seen in the > > reality, unfortunately... > > > > > > Takashi > > > > There are some good applications for it, but I have not got round to > writing them yet! Me too ;) But, I remember some difficulties regarding the timestamping at the last time I tried (quite ago). The timestamp is somewhat hard to use because it's updated at each pointer or status update although I wanted to get the exact time only at the period boundary. Maybe these usability issues should be sorted out all together. Takashi ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV