[4.2.y-ckt stable] Patch "ALSA: usb-audio: Skip volume controls triggers hangup on Dell USB Dock" has been added to the 4.2.y-ckt tree

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

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

to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue

This patch is scheduled to be released in version 4.2.8-ckt9.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 4.2.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

---8<------------------------------------------------------------

>From 232ede6b5ece4daae6d359a37a0a7a8e6d5ab683 Mon Sep 17 00:00:00 2001
From: Kailang Yang <kailang at realtek.com>
Date: Tue, 12 Apr 2016 10:55:03 +0800
Subject: ALSA: usb-audio: Skip volume controls triggers hangup on Dell USB
 Dock

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]

Signed-off-by: Kailang Yang <kailang at realtek.com>
Signed-off-by: Takashi Iwai <tiwai at suse.de>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 sound/usb/mixer_maps.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/sound/usb/mixer_maps.c b/sound/usb/mixer_maps.c
index ddca654..1f8fb0d9 100644
--- a/sound/usb/mixer_maps.c
+++ b/sound/usb/mixer_maps.c
@@ -349,6 +349,16 @@ static struct usbmix_name_map bose_companion5_map[] = {
 };

 /*
+ * 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_maps[] = {
 		.map = aureon_51_2_map,
 	},
 	{
+		.id = USB_ID(0x0bda, 0x4014),
+		.map = dell_alc4020_map,
+	},
+	{
 		.id = USB_ID(0x0dba, 0x1000),
 		.map = mbox1_map,
 	},
--
2.7.4