ALSA: hda/generic: Add option to enforce preferred_dacs pairs

The generic parser accepts the preferred_dacs[] pairs as a hint for
assigning a DAC to each pin, but this hint doesn't work always
effectively.  Currently it's merely a secondary choice after the trial
with the path index failed.  This made sometimes it difficult to
assign DACs without mimicking the connection list and/or the badness
table.

This patch adds a new flag, obey_preferred_dacs, that changes the
behavior of the parser.  As its name stands, the parser obeys the
given preferred_dacs[] pairs by skipping the path index matching and
giving a high penalty if no DAC is assigned by the pairs.  This mode
will help for assigning the fixed DACs forcibly from the codec
driver.

Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20201127141104.11041-1-tiwai@suse.deSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/hda/hda_generic.c

@@ -1364,16 +1364,20 @@ static int try_assign_dacs(struct hda_codec *codec, int num_outs,
 		struct nid_path *path;
 		hda_nid_t pin = pins[i];
 
+		if (!spec->obey_preferred_dacs) {
 			path = snd_hda_get_path_from_idx(codec, path_idx[i]);
 			if (path) {
 				badness += assign_out_path_ctls(codec, path);
 				continue;
 			}
+		}
 
 		dacs[i] = get_preferred_dac(codec, pin);
 		if (dacs[i]) {
 			if (is_dac_already_used(codec, dacs[i]))
 				badness += bad->shared_primary;
+		} else if (spec->obey_preferred_dacs) {
+			badness += BAD_NO_PRIMARY_DAC;
 		}
 
 		if (!dacs[i])

sound/pci/hda/hda_generic.h

@@ -237,6 +237,7 @@ struct hda_gen_spec {
 	unsigned int power_down_unused:1; /* power down unused widgets */
 	unsigned int dac_min_mute:1; /* minimal = mute for DACs */
 	unsigned int suppress_vmaster:1; /* don't create vmaster kctls */
+	unsigned int obey_preferred_dacs:1; /* obey preferred_dacs assignment */
 
 	/* other internal flags */
 	unsigned int no_analog:1; /* digital I/O only */