[PATCH 2/2] ALSA: usb-audio: Skip mixer creation on M-Audio Venom

[Federico Valentín Andrade]

The M-Audio Venom (0763:2084) does not answer any GET_CUR request
of its feature units, hanging up the USB microcontroller and
"responding" with timeouts. So the mixer building lasts around 47
seconds, and the device does not stream at all.

The same GET_CUR requests issued through libusb (with no kernel
driver bound) complete correctly and blazingly fast. So it seems
to only happen during the initial probe.

I defined an explicit composite quirk to bypass the mixer creation,
as it is not needed (the synth already comes with volume controls).

With both this and the device flag applied, the synth works
flawlessly.

Signed-off-by: Federico Valentín Andrade <fandrade@xxxxxxxxxxxxxxx>
---
Tested on 7.1.8-arch1-3 xHCI (Intel PCH).

alsa-info: https://pastebin.com/Kf4SCkyT

 sound/usb/quirks-table.h | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/sound/usb/quirks-table.h b/sound/usb/quirks-table.h
index 0a3d39b838..dd02c6294e 100644
--- a/sound/usb/quirks-table.h
+++ b/sound/usb/quirks-table.h
@@ -1814,6 +1814,28 @@ YAMAHA_DEVICE(0x7010, "UB99"),
 		}
 	}
 },
+{
+	/*
+	 * M-Audio Venom
+	 *
+	 * The AudioControl interface times out on every GET_CUR request,
+	 * which adds around 47 seconds to the card registration and
+	 * freezes the device, blocking streaming.
+	 * Using an explicit composite quirk to skip the mixer entirely.
+	 */
+	USB_DEVICE_VENDOR_SPEC(0x0763, 0x2084),
+	QUIRK_DRIVER_INFO {
+		.vendor_name = "M-Audio",
+		.product_name = "Venom",
+		QUIRK_DATA_COMPOSITE {
+			{ QUIRK_DATA_IGNORE(0) },
+			{ QUIRK_DATA_STANDARD_AUDIO(1) },
+			{ QUIRK_DATA_STANDARD_AUDIO(2) },
+			{ QUIRK_DATA_STANDARD_MIDI(3) },
+			QUIRK_COMPOSITE_END
+		}
+	}
+},
 
 /* Casio devices */
 {
-- 
2.55.0