> -----Original Message----- > From: Jaroslav Kysela [mailto:perex@xxxxxxxx] > Sent: Friday, August 20, 2010 3:20 PM > To: Harsha, Priya > Cc: alsa-devel@xxxxxxxxxxxxxxxx > Subject: Re: need help understanding overrun/underrun > > On Fri, 20 Aug 2010, Harsha, Priya wrote: > > > Hi > > > > I had modified the arecord application to call snd_pcm_writei() with the > > output of snd_pcm_readi(). Basically a loopback. > > > > When we execute, I see the calls return EPIPE (lot of overruns and a few > > underruns). Can anyone help me understand why there are underrun/overrun > > being printed? Is it because of the serial call of reads and writes? Is > > there any issue with the driver I am using? Can you suggest some ways to > > overcome these messages? > > You must queue playback with more samples at the beginning (to > setup the output latency) otherwise you get the output underrun > immediatelly. See alsa-lib/test/latency.c for an example. If I do that, initially I don't see underrun. But I see a lot of overrun. I am doing readi() followed by writei() in a loop of small buffer sizes, Is that an expected behavior to see such overrun? > > Jaroslav > > ----- > Jaroslav Kysela <perex@xxxxxxxx> > Linux Kernel Sound Maintainer > ALSA Project, Red Hat, Inc. _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
