This codec (among others) has a hidden set of audio routes, apparently
designed to allow PC Beep output without a mixer widget on the output
path, which are controlled by an undocumented Realtek vendor register.
The default configuration of these routes means that certain inputs
aren't accessible, necessitating driver control of the register.
However, Realtek has provided no documentation of the register, instead
opting to fix issues by providing magic numbers, most of which have been
at least somewhat erroneous. These magic numbers then get copied by
others into model-specific fixups, leading to a fragmented and buggy set
of configurations.
To get out of this situation, I've reverse engineered the register by
flipping bits and observing how the codec's behavior changes. This
commit documents my findings. It does not change any code.
Cc: stable@vger.kernel.org
Signed-off-by: Thomas Hebb <tommyhebb@gmail.com>
Link: https://lore.kernel.org/r/bd69dfdeaf40ff31c4b7b797c829bb320031739c.1585584498.git.tommyhebb@gmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
A simple reformat with the description list of ReST, and the content
was kept as is, but renamed as Documentation/sound/hd-audio/models.rst.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
The original HD-Audio.txt was already in asciidoc format, so it's a
simple conversion in the end.
A new subdirectory, Documentation/sound/hd-audio, is created and the
document is moved there with another file name to match better with
the recent Documentation tree structure.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
