Applications that open /dev/audio may use the AUDIO_GETDEV ioctl(2) to determine which audio device is being used. The audioens driver returns the string SUNW,audioens in the name field of the audio_device structure. The version field contains a letter (defined in the table below) and the config field contains the string onboard1.

The driver works on Sun architectures that support PCI slots, including Sparc 32 bit, Sparc 64 bit, and IA 32 bit.

Different cards provide different input and output connectors and may internally hardwire these connectors. SpeakerOut implies an internal audio amplifier and LineOut implies the output is to go to an amplified speaker. The audioens driver routes output data to both SpeakerOut and LineOut. The audioens driver supports input selection from LineIn or Microphone.

Platform Type: Sun4u/IA

Version: a

Line Out: Yes

Headphone: No

Int. Speaker: Yes

Line In: Yes

Microphone: Yes

CD-ROM: No

The configuration file /kernel/drv/audioens.conf is used to configure the audioens driver and determines whether the audio mixer is enabled or disabled. See the mixer(7I) manual page for details. You can change the audio mixer mode at any time using the sdtaudiocontrol(1) or mixerctl(1) applications.

The audioens audio device supports the audio data formats shown below. When the audio mixer is disabled and the device is opened for simultaneous play and record, the input and output data formats may differ. Some sample rates are supported when the mixer is disabled (D) that are not supported when the mixer is enabled (E), due to the overly high computational overhead for sample rate conversion.

Supported data formats.

Because the audioens device manipulates buffers of audio data, the reported input and output sample counts will vary at any given time from the actual sample count by no more than the size of the buffers the audioens driver is transferring. In general, programs should not rely on the absolute accuracy of the play.samples and record.samples fields of the audio_info structure. (See audio(7I)).

The driver determines how often play and record interrupts take place. For playing audio, the driver determines how often and how much audio is requested from the audio mixer. The impact of interrupts on recording is minimal. However, if a very small read buffer size is set, the record interrupt rate should be increased to prevent the buffer from overflowing. You tune the play and record interrupt rates using the /kernel/drv/audioens.conf file.

As described in the mixer(7I) and audio(7I) man pages, you can request asynchronous notification of changes in the state of an audio device.