[ 07/32] ALSA: usb-audio - Fix invalid volume resolution on Logitech HD webcam c270

From: Greg Kroah-Hartman
Date: Tue Jun 11 2013 - 16:34:22 EST


3.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Takashi Iwai <tiwai@xxxxxxx>

commit 11e7064f35bb87da8f427d1aa4bbd8b7473a3993 upstream.

USB audio driver spews an error message when probing Logitech HD
webcam c270:
ALSA mixer.c:1300 usb_audio: Warning! Unlikely big volume range (=6144), cval->res is probably wrong.
ALSA mixer.c:1304 usb_audio: [5] FU [Mic Capture Volume] ch = 1, val = 1536/7680/1

Obviously the device needs a fixed volume resolution (cval->res = 384)
like other Logitech devices.

Bugzilla: https://bugzilla.novell.com/show_bug.cgi?id=821735

Reported-and-tested-by: Cristian RodrÃguez <crrodriguez@xxxxxxxxxxxx>
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
sound/usb/mixer.c | 1 +
1 file changed, 1 insertion(+)

--- a/sound/usb/mixer.c
+++ b/sound/usb/mixer.c
@@ -822,6 +822,7 @@ static void volume_control_quirks(struct
case USB_ID(0x046d, 0x0808):
case USB_ID(0x046d, 0x0809):
case USB_ID(0x046d, 0x081d): /* HD Webcam c510 */
+ case USB_ID(0x046d, 0x0825): /* HD Webcam c270 */
case USB_ID(0x046d, 0x0991):
/* Most audio usb devices lie about volume resolution.
* Most Logitech webcams have res = 384.


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