I have done a lot of analysis for these type of devices and collaborated
quite a bit with Nick Weihs (author of the first patch submitted for this
including adding samsung_helper.c). More information can be found in the
issue on Github [1] including additional rationale and testing.

The existing implementation includes a large number of equalizer coef
values that are not necessary to actually init and enable the speaker
amps, as well as create a somewhat worse sound profile. Users have
reported "muffled" or "muddy" sound; more information about this including
my analysis of the differences can be found in the linked Github issue.

This patch refactors the "v2" version of ALC298_FIXUP_SAMSUNG_AMP to a much
simpler implementation which removes the new samsung_helper.c, reuses more
of the existing patch_realtek.c, and sends significantly fewer unnecessary
coef values (including removing all of these EQ-specific coef values).

A pcm_playback_hook is used to dynamically enable and disable the speaker
amps only when there will be audio playback; this is to match the behavior
of how the driver for these devices is working in Windows, and is
suspected but not yet tested or confirmed to help with power consumption.

Support for models with 2 speaker amps vs 4 speaker amps is controlled by
a specific quirk name for both types. A new int num_speaker_amps has been
added to alc_spec so that the hooks can know how many speaker amps to
enable or disable. This design was chosen to limit the number of places
that subsystem ids will need to be maintained: like this, they can be
maintained only once in the quirk table and there will not be another
separate list of subsystem ids to maintain elsewhere in the code.

Also updated the quirk name from ALC298_FIXUP_SAMSUNG_AMP2 to
ALC298_FIXUP_SAMSUNG_AMP_V2_.. as this is not a quirk for "Amp #2" on
ALC298 but is instead a different version of how to handle it.

More devices have been added (see Github issue for testing confirmation),
as well as a small cleanup to existing names.

[1]: https://github.com/thesofproject/linux/issues/4055#issuecomment-2323411911Signed-off-by: Joshua Grisham <josh@joshuagrisham.com>
Link: https://patch.msgid.link/20240909193000.838815-1-josh@joshuagrisham.comSigned-off-by: Takashi Iwai <tiwai@suse.de>