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Neil Armstrong authored
When using an I2S source using a different clock source (usually the I2S
audio HW uses dedicated PLLs, different from the HDMI PHY PLL), fixed
CTS values will cause some frequent audio drop-out and glitches as
reported on Amlogic, Allwinner and Rockchip SoCs setups.

Setting the CTS in automatic mode will let the HDMI controller generate
automatically the CTS value to match the input audio clock.

The DesignWare DW-HDMI User Guide explains:
  For Automatic CTS generation
  Write "0" on the bit field "CTS_manual", Register 0x3205: AUD_CTS3

The DesignWare DW-HDMI Databook explains :
  If "CTS_manual" bit equals 0b this registers contains "audCTS[19:0]"
  generated by the Cycle time counter according to specified timing.

Cc: Jernej Skrabec <jernej.skrabec@siol.net>
Cc: Maxime Ripard <maxime.ripard@bootlin.com>
Cc: Jonas Karlman <jonas@kwiboo.se>
Cc: Heiko Stuebner <heiko@sntech.de>
Cc: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: default avatarNeil Armstrong <narmstrong@baylibre.com>
Tested-by: default avatarJernej Skrabec <jernej.skrabec@siol.net>
Reviewed-by: default avatarJernej Skrabec <jernej.skrabec@siol.net>
Tested-by: default avatarDouglas Anderson <dianders@chromium.org>
Signed-off-by: default avatarAndrzej Hajda <a.hajda@samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190612085147.26971-1-narmstrong@baylibre.com
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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.