The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/third_party/kernel/+/476f44fc2cf6b8cb43e55113ce0c2605f35e2a54

commit 476f44fc2cf6b8cb43e55113ce0c2605f35e2a54
Author: Guenter Roeck <groeck@chromium.org>
Date: Fri Nov 03 08:53:39 2017

CHROMIUM: Revert "UPSTREAM: ALSA: usb-audio: add dB range mapping for some devices"

This reverts commit a14fb85d464bb6d0a1bf7f723407d4d6a544379d.

Commit a14fb85d464b ("UPSTREAM: ALSA: usb-audio: add dB range mapping for some
devices") exists upstream and was subsequently improved there with commit
42e3121d90f4 ("ALSA: usb-audio: Add a more accurate volume quirk for AudioQuest
DragonFly"). The patch in chromeos-4.4 partially reverts that second commit for
no good reason and needs to be reverted.

BUG= chromium:780882 
TEST=Build on system using DragonFly and test sound

Change-Id: I5d5ffd2da7d688f2d93c0da824995608554f36d8
Signed-off-by: Guenter Roeck <groeck@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/751761
Reviewed-by: Cheng-Yi Chiang <cychiang@chromium.org>

[modify] https://crrev.com/476f44fc2cf6b8cb43e55113ce0c2605f35e2a54/sound/usb/mixer_maps.c