Add a READONLY property flag to makr properties READONLY
Set the base_volume and volume_step in the acp device
Send the base volume and step as REAONLY properties. Use these
in pulse layer.
Add HARDWARE flag to mark a property that does some hardware control.
Mark the device volume/mute property as HARDWARE or not.
Use the HARDWARE property in pulse to set the right flags.
libacp is a port and wrapper around the pulseaudio card profile code.
It uses a set of templates for construct a card profile and mixer port
settings. It also has support for UCM when available for the hardware.
