Patch "ALSA: usb-audio: Fix parsing descriptor of UAC2 processing unit" has been added to the 4.15-stable tree

This is a note to let you know that I've just added the patch titled

ALSA: usb-audio: Fix parsing descriptor of UAC2 processing unit

to the 4.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
alsa-usb-audio-fix-parsing-descriptor-of-uac2-processing-unit.patch
and it can be found in the queue-4.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Kirill Marinushkin <[email protected]>
Date: Mon, 19 Mar 2018 07:11:08 +0100
Subject: ALSA: usb-audio: Fix parsing descriptor of UAC2 processing unit

From: Kirill Marinushkin <[email protected]>

commit a6618f4aedb2b60932d766bd82ae7ce866e842aa upstream.

Currently, the offsets in the UAC2 processing unit descriptor are calculated incorrectly. It causes an issue when connecting the device which provides such a feature:

~~~~

[84126.724420] usb 1-1.3.1: invalid Processing Unit descriptor (id 18)

~~~~

After this patch is applied, the UAC2 processing unit inits w/o this error.

---
 include/uapi/linux/usb/audio.h |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

@@ -370,7 +370,7 @@ static inline __u8 uac_processing_unit_b
 {
 	return (protocol == UAC_VERSION_1) ?
 		desc->baSourceID[desc->bNrInPins + 4] :
-		desc->baSourceID[desc->bNrInPins + 6];
+		2; /* in UAC2, this value is constant */
 }
 
 static inline __u8 *uac_processing_unit_bmControls(struct uac_processing_unit_descriptor *desc,

@@ -378,7 +378,7 @@ static inline __u8 *uac_processing_unit_
 {
 	return (protocol == UAC_VERSION_1) ?
 		&desc->baSourceID[desc->bNrInPins + 5] :
-		&desc->baSourceID[desc->bNrInPins + 7];
+		&desc->baSourceID[desc->bNrInPins + 6];
 }
 
 static inline __u8 uac_processing_unit_iProcessing(struct uac_processing_unit_descriptor *desc,

Patches currently in stable-queue which might be from [email protected] are

queue-4.15/alsa-usb-audio-fix-parsing-descriptor-of-uac2-processing-unit.patch