From mboxrd@z Thu Jan 1 00:00:00 1970 From: Abramo Bagnara Subject: Re: [alsa-cvslog] CVS: alsa-lib/src/pcm pcm.c,1.222,1.223 Date: Wed, 09 Oct 2002 09:06:42 +0200 Sender: alsa-devel-admin@lists.sourceforge.net Message-ID: <3DA3D582.4161E6F3@libero.it> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Return-path: Errors-To: alsa-devel-admin@lists.sourceforge.net List-Help: List-Post: List-Subscribe: , List-Unsubscribe: , List-Archive: To: Jaroslav Kysela Cc: alsa-devel@lists.sourceforge.net List-Id: alsa-devel@alsa-project.org Jaroslav Kysela wrote: > > Update of /cvsroot/alsa/alsa-lib/src/pcm > In directory usw-pr-cvs1:/tmp/cvs-serv27101 > > Modified Files: > pcm.c > Log Message: > Fixes in documentation for fast status > > Index: pcm.c > =================================================================== > RCS file: /cvsroot/alsa/alsa-lib/src/pcm/pcm.c,v > retrieving revision 1.222 > retrieving revision 1.223 > diff -u -r1.222 -r1.223 > --- pcm.c 21 Sep 2002 19:01:24 -0000 1.222 > +++ pcm.c 9 Oct 2002 06:13:57 -0000 1.223 > @@ -373,16 +373,21 @@ > parameters - avail_max and overrange are reset to zero after the status > call. > > -\subsection pcm_status_fast Obtaining fast device status > +\subsection pcm_status_fast Obtaining device status fast > > The function \link ::snd_pcm_avail_update \endlink updates the current > available count of samples for writing (playback) or filled samples for > -reading (capture). > +reading (capture). It is a light version of > +\link ::snd_pcm_status_get_avail \endlink, because it does not require > +the user <-> kernel context switch, but the value is less accurate, > +because ring buffer pointers are updated in kernel drivers only when > +an interrupt occurs. >

Wrong here: 1) snd_pcm_status_get_avail is only an accessor method 2) snd_pcm_avail_update call is *needed* for chained PCM (to call snd_pcm_status does not do the needed things). -- Abramo Bagnara mailto:abramo.bagnara@libero.it Opera Unica Phone: +39.546.656023 Via Emilia Interna, 140 48014 Castel Bolognese (RA) - Italy ------------------------------------------------------- This sf.net email is sponsored by:ThinkGeek Welcome to geek heaven. http://thinkgeek.com/sf