Applications that open /dev/audio may use the AUDIO_GETDEV ioctl(2) to determine which audio device is being used. The audiocs driver will return the string SUNW,CS4231 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.

Key to the above table: Ver = Version. Out = Line Out. Speaker = Internal Speaker. In = Line In. Mic. = Microphone. CD = CD-ROM.

The audiocs device provides support for the internal speaker, headphone, line out, line in, microphone, and on some platforms, internal CD-ROM audio in. The play.avail_ports and record.avail_ports fields retrieved by the AUDIO_GETINFO ioctl (see audio(7I)) report which ports are available. The play.mod_ports and record.mod_ports fields indicate which ports may be manipulated.

The configuration file /kernel/drv/audiocs.conf is used to configure the audiocs driver so that the audio mixer is enabled or disabled. See the mixer(7I) manual page for details. The audio mixer's mode may be changed at any time using the mixerctl(1) or sdtaudiocontrol(1)() applications.

The audiocs device supports the audio formats listed in the following table. When the audio mixer is in compatibility mode and the device is open for simultaneous play and record, the input and output data formats must match. Some sample rates are supported in compatibility mode (C) that are not supported in mixer mode (M). This is due to the computational overhead for sample rate conversion being too high.

At any given time the reported input and output sample counts will vary from the actual sample count by no more than the size of the buffers the audiocs 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.

The driver determines how often play and record interrupts should occur. For playing audio, this 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. The play and record interrupt rates are tunable in the /kernel/drv/audiocs.conf file.

As described in the audio(7I) and mixer(7I) man pages, it is possible to request asynchronous notification of changes in the state of an audio device.