From 5dae5fd24071319bb67d3375217d5b0b6d16cb0b Mon Sep 17 00:00:00 2001 From: Eldad Zack Date: Wed, 28 Nov 2012 23:55:36 +0100 Subject: [PATCH] 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 Signed-off-by: Takashi Iwai --- sound/usb/mixer.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c index b0fc6ae037a2..4eacbe2e2d64 100644 --- a/sound/usb/mixer.c +++ b/sound/usb/mixer.c @@ -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 */ -- 2.30.2