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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>
This commit is contained in:
Eldad Zack 2012-11-28 23:55:36 +01:00 committed by Takashi Iwai
parent 9f81410592
commit 5dae5fd240
1 changed files with 12 additions and 1 deletions
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13
sound/usb/mixer.c
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@ -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 */