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

BugLink: http://bugs.launchpad.net/bugs/1759655
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.

Fixes: 23caaf19b11e ("ALSA: usb-mixer: Add support for Audio Class v2.0")
Signed-off-by: Kirill Marinushkin <k.marinushkin@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>

diff --git a/include/uapi/linux/usb/audio.h b/include/uapi/linux/usb/audio.h
index 17a022c5b4144c48f0bb071d53d619f63983fbdb..da3315ed1bcde6be19093f32ae26064b7284ed02 100644 (file)
--- a/include/uapi/linux/usb/audio.h
+++ b/include/uapi/linux/usb/audio.h
@@ -370,7 +370,7 @@ static inline __u8 uac_processing_unit_bControlSize(struct uac_processing_unit_d
 {
        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_bmControls(struct uac_processing_unit_de
 {
        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,