I'm using an Alienware 15 R2 and had to use the alienware quirks to
get my headphone output working.

I fixed it by adding, SND_PCI_QUIRK(0x1028, 0x0708, "Alienware 15 R2
2016", QUIRK_ALIENWARE) to the patch.
Signed-off-by: Sven Hahne <hahne@zeitkunst.eu>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>