[alsa-devel] Hidden rate conversion, and Alsa configuration

[stan]

On Fri, 27 Jul 2007 10:53:16 -0700
stan <stanl at cox.net> wrote:

> On Fri, 27 Jul 2007 11:59:53 -0400
> "Lee Revell" <rlrevell at joe-job.com> wrote:
> 
> > On 7/27/07, Alan Horstmann <gineera at aspect135.co.uk> wrote:
> > > Could you give pointers as to how to modify Alsa configuration so
> > > that rate conversion can never happen, as I would prefer to have
> > > an error accessing the sound card rather than unknown conversion,
> > > which in my use should never be neccesary anyway.
> > 
> > Simply open the hw device rather than the default, dmix, or plughw
> > device.
> > 
> > Lee
> 
> When I use the following call with device_to_use == "plughw:0,0"
> it works just fine.  When I try to use device_to_use == "hw:0,0"
> it gives a segmentation fault.  Is there a special initialization
> needed to use the hw plug?
> 
> err = snd_pcm_open (&alsa_dev, device_to_use,
> SND_PCM_STREAM_PLAYBACK, 0);
> 
I see from this alsa-project doc page 
http://alsa-project.org/alsa-doc/alsa-lib/pcm__hw_8c.html#d0275f35954d3681fd8d016d5cf26749
that there are special functions
for this : snd_pcm_hw_open or _snd_pcm_hw_open.