Edirol/Roland M-16DX not detected properly
Submitted by Lasse Kärkkäinen
Assigned to pul..@..op.org
3 [M16DX ]: USB-Audio - M-16DX EDIROL M-16DX at usb-0000:02:00.0-2, high speed
M-16DX is a studio mixer / capture device with 18-channel capture and 2-channel playback. Pulseaudio does not detect any capture functionality, probably due to the high channel count. For playback, separate analog and SPDIF outputs are detected by Pulseaudio (probably because ALSA exposes a iec958 device) but as far as I know, M-16DX is unable to do SPDIF pass-through. Also, playback is broken due to a known ALSA bug that is unlikely to get fixed.
I suggest detecting the device for capture only, using 18 channels as it doesn't support any less. The only sample format supported is S32_LE. The sample rate is configured on the hardware and cannot be changed by the host (44.1/48/96 kHz).
The capture channels should be labeled as follows: Mono 1 (Mic/Line) Mono 2 (Mic/Line) Mono 3 (Mic/Line) Mono 4 (Mic/Line) Stereo 5L/6R (Line) Stereo 7L/8R (Line) Stereo 9L/10R (Line) Stereo 11L/12R (Line / SPDIF) Stereo 13L/14R (Aux Return 1 / USB) Stereo 15L/16R (Aux Return 2) Stereo Main Mix (Monitor)
The numbers (with L/R) and "MAIN MIX" are printed on the device itself.
The last two channels (17-18) return the master output of the device, right before the master volume control.
No capture or playback volume controls are exposed via alsamixer (instead, the device has hardware knobs).