wsbell, wsbelldevprint —
wscons system bell support
The wsbell module is a component of the
  wscons(9) framework, providing
  keyboard-independent bell support. All of the support is provided by the
  wsbell(4) device driver, which
  must be a child of the hardware device driver. The only hardware device
  drivers that can provide a wsbell facility are
  speaker(4) devices.
Speaker drivers providing support for wscons bell devices will make use of the
  following data types:
  - struct wsbelldev_attach_args
- A structure used to attach the
      wsbell(4) child device. It
      has the following members:
    
  
  - wsbelldevprint(aux,
    pnp)
- The default wsbell printing routine used by
      config_found(). (see
      autoconf(9)).
Speaker drivers which want to use the wsbell module must be a parent to the
  wsbell(4) device and provide an
  attachment interface. To attach the
  wsbell(4) device, the speaker
  driver must allocate and populate a
  wsbelldev_attach_args structure with a pointer to the
  parent's device structure as an access cookie and callconfig_found() to perform the attach (see
  autoconf(9)).
When a bell event is received on a
  wsdisplay(4) device the
  system bell is sounded.
The wscons subsystem is implemented within the directory
  sys/dev/wscons. The wsbell
  module itself is implement within the file
  sys/dev/wscons/wsbell.c.
  ioctl(2) operations are listed in
  sys/dev/wscons/wsconsio.h.