Commit 5dae5fd2 authored Nov 28, 2012 by Eldad Zack Committed by Takashi Iwai Nov 29, 2012

ALSA: usb-audio: skip UAC2 EFFECT_UNIT



Current code mishandles the case where the device is a UAC2
and the bDescriptorSubtype is a UAC2 Effect Unit (0x07).
It tries to parse it as a Processing Unit (which is similar to two
other UAC1 units with overlapping subtypes), but since the structure
is different (See: 4.7.2.10, 4.7.2.11 in UAC2 standard), the parsing
is done incorrectly and prevents the device from initializing.
For now, just ignore the unit.

Signed-off-by: Eldad Zack <eldad@fogrefinery.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

parent 9f814105

sound/usb/mixer.c

+12 −1

Original line number	Diff line number	Diff line
		@@ -723,8 +723,19 @@ static int check_input_term(struct mixer_build *state, int id, struct usb_audio_
		return 0;
		}
		case UAC1_PROCESSING_UNIT:
		case UAC1_EXTENSION_UNIT: {
		case UAC1_EXTENSION_UNIT:
		/* UAC2_PROCESSING_UNIT_V2 */
		/* UAC2_EFFECT_UNIT */ {
		struct uac_processing_unit_descriptor *d = p1;

		if (state->mixer->protocol == UAC_VERSION_2 &&
		hdr[2] == UAC2_EFFECT_UNIT) {
		/* UAC2/UAC1 unit IDs overlap here in an
		* uncompatible way. Ignore this unit for now.
		*/
		return 0;
		}

		if (d->bNrInPins) {
		id = d->baSourceID[0];
		break; /* continue to parse */

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