ALSA: hda/realtek - Fix speaker output regression on Thinkpad T570

tiwai · tiwai · commit 54947cd64c1b · 2018-12-03T10:44:15.000+01:00
We've got a regression report for some Thinkpad models (at least T570s) which shows the too low speaker output volume. The bisection leaded to the commit 61fcf8e ("ALSA: hda/realtek - Enable Thinkpad Dock device for ALC298 platform"), and it's basically adding the two pin configurations for the dock, and looks harmless. The real culprit seems, though, that the DAC assignment for the speaker pin is implicitly assumed on these devices, i.e. pin NID 0x14 to be coupled with DAC NID 0x03. When more pins are configured by the commit above, the auto-parser changes the DAC assignment, and this resulted in the regression. As a workaround, just provide the fixed pin / DAC mapping table for this Thinkpad fixup function. It's no generic solution, but the problem itself is pretty much device-specific, so must be good enough. Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1554304 Fixes: 61fcf8e ("ALSA: hda/realtek - Enable Thinkpad Dock device for ALC298 platform") Cc: <stable@vger.kernel.org> Reported-and-tested-by: Jeremy Cline <jcline@redhat.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/pci/hda/patch_realtek.c b/sound/pci/hda/patch_realtek.c
@@ -4988,9 +4988,18 @@ static void alc_fixup_tpt470_dock(struct hda_codec *codec,
 		{ 0x19, 0x21a11010 }, /* dock mic */
 		{ }
 	};
+	/* Assure the speaker pin to be coupled with DAC NID 0x03; otherwise
+	 * the speaker output becomes too low by some reason on Thinkpads with
+	 * ALC298 codec
+	 */
+	static hda_nid_t preferred_pairs[] = {
+		0x14, 0x03, 0x17, 0x02, 0x21, 0x02,
+		0
+	};
 	struct alc_spec *spec = codec->spec;
 
 	if (action == HDA_FIXUP_ACT_PRE_PROBE) {
+		spec->gen.preferred_dacs = preferred_pairs;
 		spec->parse_flags = HDA_PINCFG_NO_HP_FIXUP;
 		snd_hda_apply_pincfgs(codec, pincfgs);
 	} else if (action == HDA_FIXUP_ACT_INIT) {
