ALSA: dummy - Add more description

    or input, but you may use this module for any application which

    requires a sound card (like RealPlayer).

    pcm_devs       - Number of PCM devices assigned to each card

                     (default = 1, up to 4)

    pcm_substreams - Number of PCM substreams assigned to each PCM

                     (default = 8, up to 16)

    hrtimer        - Use hrtimer (=1, default) or system timer (=0)

    When multiple PCM devices are created, snd-dummy gives different

    behavior to each PCM device:

      0 = interleaved with mmap support

      1 = non-interleaved with mmap support

      2 = interleaved without mmap 

      3 = non-interleaved without mmap

    The power-management is supported.

  Module snd-echo3g