[linux-audio-dev] SNDCTL_DSP_CHANNELS problem setting to mono

[Jussi Laako]

On Fri, 2003-07-18 at 23:48, Overcast, Isaac wrote:

> int numChannels = 1 ;
> ioctl( deviceHandle, SNDCTL_DSP_CHANNELS, &numChannels )

> This call doesn't fail, but when it returns 'numChannels' == 2. Portaudio
> detects this and promptly dies.
> 
> Now, i just can't figure out if the problem is the onboard sound device is
> just so crappy that it doesn't bother to support mono, or if there is some
> wierd kernel module i can build that will fix this issue.

Either the driver nor hardware supports 1 channel mode or the driver is
broken. It should return the actual number of channels set. For example:

  2002/07/18 20:41:12 Request /dev/dsp9: ch 8 fs 96000 fmt 1000h
  2002/07/18 20:41:12 Open /dev/dsp9: ch 8 fs 96000 fmt 1000h frag 4096
(4096) bytes

  2003/01/18 02:04:34 Request /dev/dsp9: ch 2 fs 44100 fmt 1000h
  2003/01/18 02:04:34 Open /dev/dsp9: ch 2 fs 44100 fmt 1000h frag 1024
(4096) bytes


-- 
Jussi Laako <jussi.laako at pp.inet.fi>