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The kernel has 2 drivers for the Low Power Engine audio-block on
Bay- and Cherry-Trail SoCs. The old SST driver and the new SOF
driver. If both drivers are enabled then the kernel will default
to using the old SST driver, unless told otherwise through the
snd_intel_dspcfg.dsp_driver module-parameter.

Add a boolean SND_INTEL_BYT_PREFER_SOF Kconfig option, which when set to Y
will make the kernel default to the new SOF driver instead.
The option defaults to n, preserving the current behavior.

Making this configurable will help distributions such as Fedora:
https://fedoraproject.org/w/index.php?title=Changes/SofDefaultForIntelLpe


to test using SOF on BYT/CHT during the transition phase where we
have both drivers (eventually the old driver and this option will
be removed).

Note that this drops the acpi_config_table[] containing 2 entries per ACPI
hardware-id if both drivers are enabled. snd_intel_acpi_dsp_find_config()
will always return the first hit, so we only need a single entry with the
flags value set depending on the Kconfig settings.
Suggested-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20210208135919.135600-1-hdegoede@redhat.com

Signed-off-by: Takashi Iwai <tiwai@suse.de>