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

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>

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,