ALSA: usb-audio: Add support for Pioneer DJ DJM-S11

The Pioneer DJ DJM-S11, a professional 2-port DJ mixer, is currently not
recognized as an audio interface and therefore not usable on Linux. This
patch enables its full audio functionality.

Like other mixers in the Pioneer DJ DJM family, the DJM-S11 uses
vendor-specific USB class descriptors (0xff) and requires custom mixer
quirks to expose the hardware's input capture routing and volume
controls.

Add the USB vendor and product ID (2b73:0037) to quirks-table.h, mapping
the control interface (Interface 0) to trigger the standard mixer quirks,
and establishing the audio formats for the playback and capture streams.

Control interface 3 is likely related to the touchscreen which is
capable to display waveforms, etc. This functionality is not supported.

In mixer_quirks.c, add the DSP routing options for the DJM-S11. This
creates the ALSA kcontrols for selecting the capture sources (Phono,
Line, Post-fader, etc.) and initializes the default DSP state during
the device probe.

Note that the DJM-S11's capture endpoint clock is strictly slaved to
its playback endpoint. Capturing audio (e.g., timecode vinyl DVS input)
physically requires an active playback stream on the output channels
to feed the master word clock back to the capture stage. Userspace
audio servers (such as PipeWire or JACK) should be configured in
full-duplex mode or have automatic node suspension disabled to maintain
the clock line and prevent I/O errors during capture.

Signed-off-by: Federico Beffa <beffa@fbengineering.ch>
Link: https://patch.msgid.link/20260625115340.823184-1-beffa@fbengineering.ch
Signed-off-by: Takashi Iwai <tiwai@suse.de>

0 files changed, 0 insertions, 0 deletions