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Alex Stanoev ac237c28d5 ALSA: ca0106: Disable IZD on SB0570 DAC to fix audio pops
The Creative Audigy SE (SB0570) card currently exhibits an audible pop
whenever playback is stopped or resumed, or during silent periods of an
audio stream. Initialise the IZD bit to the 0 to eliminate these pops.

The Infinite Zero Detection (IZD) feature on the DAC causes the output
to be shunted to Vcap after 2048 samples of silence. This discharges the
AC coupling capacitor through the output and causes the aforementioned
pop/click noise.

The behaviour of the IZD bit is described on page 15 of the WM8768GEDS
datasheet: "With IZD=1, applying MUTE for 1024 consecutive input samples
will cause all outputs to be connected directly to VCAP. This also
happens if 2048 consecutive zero input samples are applied to all 6
channels, and IZD=0. It will be removed as soon as any channel receives
a non-zero input". I believe the second sentence might be referring to
IZD=1 instead of IZD=0 given the observed behaviour of the card.

This change should make the DAC initialisation consistent with
Creative's Windows driver, as this popping persists when initialising
the card in Linux and soft rebooting into Windows, but is not present on
a cold boot to Windows.

Signed-off-by: Alex Stanoev <alex@astanoev.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2018-10-29 16:59:06 +01:00
arch libnvdimm/dax 4.19-rc8 2018-10-14 08:34:31 +02:00
block
certs
crypto
Documentation ASoC: Updates for v5.0/v4.20 2018-10-22 23:26:37 +02:00
drivers Merge branch 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux 2018-10-14 08:33:35 +02:00
firmware
fs libnvdimm/dax 4.19-rc8 2018-10-14 08:34:31 +02:00
include ASoC: Updates for v5.0/v4.20 2018-10-22 23:26:37 +02:00
init
ipc
kernel
lib
LICENSES
mm mm/thp: fix call to mmu_notifier in set_pmd_migration_entry() v2 2018-10-13 09:31:02 +02:00
net
samples
scripts
security
sound ALSA: ca0106: Disable IZD on SB0570 DAC to fix audio pops 2018-10-29 16:59:06 +01:00
tools
usr
virt
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS Merge branch 'asoc-4.20' into asoc-next 2018-10-21 16:59:23 +01:00
Makefile Linux 4.19-rc8 2018-10-15 07:20:24 +02:00
README

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.
See Documentation/00-INDEX for a list of what is contained in each file.

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.