I'm developing my first sound card driver in Ubuntu with ALSA.Implementing a volume control for the sound card I stumbled upon a few questions.1) For the function that is assigned to snd_kcontrol_new.info, I'm trying to understand the logic behind choosing the values of snd_ctl_elem_info.value.integer.min and max. my sound card can go between -100db and 0db, how do I decide if I map it to 0-100 in the snd_ctl_elem_info.value.integer.min/max or 0-15, or any other range?2) I'm struggling to understand the difference between the control names PCM Playback Volume, Master Playback Volume, and Playback Volume.Thanks for the answers, and apologies if the questions are very trivial, but I couldn't find a good explanation to them.
ALSA sounds card volume range numbers, and Difference between Control Names
linux kernel;drivers;audio;kernel modules;alsa
The control values typically are just the hardware's register values.The mapping between control values and dB values is done with TLV metadata.PCM applies to the sound played through the PCM device, while Master applies to all sounds played.