ALSA: realtek/alc288 fix headphone for MS Surface 2/3
The Surface Pro 2 and 3 have a strange headphone frequency response
and miss most of the bass. I discovered connecting the HP out to the
main DAC fixes this. Maybe the other is mono or intentionally filtered
signal for the built-in speakers? (At least the Lenovo Ideapad 720S
(AMD) (0x17aa, 0x3812) exhibited the same problem, but I don't have it
anymore for testing V2 changes.)
Signed-off-by: René Rebe <rene@exactco.de>
Co-developed-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://patch.msgid.link/20251120.124240.139462482701146043.rene@exactco.de