Patch "ALSA: usb-audio: Skip volume controls triggers hangup on Dell USB Dock" has been added to the 4.4-stable tree

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

ALSA: usb-audio: Skip volume controls triggers hangup on Dell USB Dock

to the 4.4-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-skip-volume-controls-triggers-hangup-on-dell-usb-dock.patch
and it can be found in the queue-4.4 subdirectory.

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

From: Kailang Yang <[email protected]>
Date: Tue, 12 Apr 2016 10:55:03 +0800
Subject: ALSA: usb-audio: Skip volume controls triggers hangup on Dell USB Dock

From: Kailang Yang <[email protected]>

commit adcdd0d5a1cb779f6d455ae70882c19c527627a8 upstream.

This is Dell usb dock audio workaround.
It was fixed the master volume keep lower.

[Some background: the patch essentially skips the controls of a couple
of FU volumes. Although the firmware exposes the dB and the value information via the usb descriptor, changing the values (we set the min volume as default) screws up the device. Although this has been fixed in the newer firmware, the devices are shipped with the old firmware, thus we need the workaround in the driver side. -- tiwai]

---
 sound/usb/mixer_maps.c |   14 ++++++++++++++
 1 file changed, 14 insertions(+)

@@ -349,6 +349,16 @@ static struct usbmix_name_map bose_compa
 };
 
 /*
+ * Dell usb dock with ALC4020 codec had a firmware problem where it got
+ * screwed up when zero volume is passed; just skip it as a workaround
+ */
+static const struct usbmix_name_map dell_alc4020_map[] = {
+	{ 16, NULL },
+	{ 19, NULL },
+	{ 0 }
+};
+
+/*
  * Control map entries
  */
 

@@ -431,6 +441,10 @@ static struct usbmix_ctl_map usbmix_ctl_
 		.map = aureon_51_2_map,
 	},
 	{
+		.id = USB_ID(0x0bda, 0x4014),
+		.map = dell_alc4020_map,
+	},
+	{
 		.id = USB_ID(0x0dba, 0x1000),
 		.map = mbox1_map,
 	},

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

queue-4.4/alsa-hda-fixup-speaker-pass-through-control-for-nid-0x14-on-alc225.patch queue-4.4/alsa-usb-audio-skip-volume-controls-triggers-hangup-on-dell-usb-dock.patch