Ross, the main issue with ALSA these days is not the API at all. It's the cases where the people responsible for the code cannot get (easy) access to the information required to program whatever hardware mixer is present in the device.
This can be true for devices following the Intel HDA "specification" (which is still so loosely constructed when it comes to the mixer that it's barely a specification at all). It's also true for many of the USB interfaces out there - the audio/MIDI I/O part works flawlessly on Linux (thanks to iOS' "no driver" requirement), but there's no way to configure the hardware mixer. MOTU went with a web-based configuration process for some of their devices, which is truly lovely since it works on any device with a web browser. But companies like Focusrite (and many more) continue to refuse to openly provide the information required for the ALSA internals to control the hardware mixer on these devices. In some cases, they have been reverse engineered, but often only partially.
Note that the same limitation applies when using those devices on iOS: you cannot configure them fully, unless the manufacturer makes an iOS version of the "device control panel".
This can be true for devices following the Intel HDA "specification" (which is still so loosely constructed when it comes to the mixer that it's barely a specification at all). It's also true for many of the USB interfaces out there - the audio/MIDI I/O part works flawlessly on Linux (thanks to iOS' "no driver" requirement), but there's no way to configure the hardware mixer. MOTU went with a web-based configuration process for some of their devices, which is truly lovely since it works on any device with a web browser. But companies like Focusrite (and many more) continue to refuse to openly provide the information required for the ALSA internals to control the hardware mixer on these devices. In some cases, they have been reverse engineered, but often only partially.
Note that the same limitation applies when using those devices on iOS: you cannot configure them fully, unless the manufacturer makes an iOS version of the "device control panel".