1099f48457
Headphone on XPS 9350/9360 produces a background white noise. The The
noise level somehow correlates with "Headphone Mic Boost", when it sets
to 1 the noise disappears. However, doing this has a side effect, which
also decreases the overall headphone volume so I didn't send the patch
upstream.
The noise was bearable back then, but after commit 717f43d81afc ("ALSA:
hda/realtek - Update headset mode for ALC256") the noise exacerbates to
a point it starts hurting ears.
So let's use the workaround to set "Headphone Mic Boost" to 1 and lock
it so it's not touchable by userspace.
Fixes: 717f43d81afc ("ALSA: hda/realtek - Update headset mode for ALC256")
BugLink: https://bugs.launchpad.net/bugs/1654448
BugLink: https://bugs.launchpad.net/bugs/1845810
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Link: https://lore.kernel.org/r/20191003043919.10960-1-kai.heng.feng@canonical.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.