ALSA: usb: Parse UAC2 extension unit like for UAC1

UAC2_EXTENSION_UNIT_V2 differs from UAC1_EXTENSION_UNIT, but can be handled in
the same way when parsing the unit. Otherwise parse_audio_unit() fails when it
sees an extension unit on a UAC2 device.

UAC2_EXTENSION_UNIT_V2 is outside the range allocated by UAC1.
Signed-off-by: Torstein Hegge <hegge@resisty.net>
Acked-by: Daniel Mack <zonque@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/usb/mixer.c

@@ -725,7 +725,8 @@ static int check_input_term(struct mixer_build *state, int id, struct usb_audio_
 		case UAC1_PROCESSING_UNIT:
 		case UAC1_EXTENSION_UNIT:
 		/* UAC2_PROCESSING_UNIT_V2 */
-		/* UAC2_EFFECT_UNIT */ {
+		/* UAC2_EFFECT_UNIT */
+		case UAC2_EXTENSION_UNIT_V2: {
 			struct uac_processing_unit_descriptor *d = p1;
 
 			if (state->mixer->protocol == UAC_VERSION_2 &&
@@ -2052,6 +2053,8 @@ static int parse_audio_unit(struct mixer_build *state, int unitid)
 			return parse_audio_extension_unit(state, unitid, p1);
 		else /* UAC_VERSION_2 */
 			return parse_audio_processing_unit(state, unitid, p1);
+	case UAC2_EXTENSION_UNIT_V2:
+		return parse_audio_extension_unit(state, unitid, p1);
 	default:
 		snd_printk(KERN_ERR "usbaudio: unit %u: unexpected type 0x%02x\n", unitid, p1[2]);
 		return -EINVAL;