ALSA: hda - Make sure mute LEDs stay on during runtime suspend (Realtek)

Some HP machines with Realtek codecs have mute LEDs connected to VREF pins.
However when these go into runtime suspend, the pin powers down and its
pin control is disabled, thus disabling the LED too.

This patch fixes that issue by making sure that the pin stays in D0 with
correct pin control.

Cc: stable@kernel.org
BugLink: https://bugs.launchpad.net/bugs/1248465
Tested-by: Franz Hsieh <franz.hsieh@canonical.com>
Signed-off-by: David Henningsson <david.henningsson@canonical.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
index 02071a5..f19cd4f 100644
--- a/sound/pci/hda/patch_realtek.c
+++ b/sound/pci/hda/patch_realtek.c
@@ -2959,6 +2959,23 @@
 		snd_hda_set_pin_ctl_cache(codec, spec->mute_led_nid, pinval);
 }
 
+/* Make sure the led works even in runtime suspend */
+static unsigned int led_power_filter(struct hda_codec *codec,
+						  hda_nid_t nid,
+						  unsigned int power_state)
+{
+	struct alc_spec *spec = codec->spec;
+
+	if (power_state != AC_PWRST_D3 || nid != spec->mute_led_nid)
+		return power_state;
+
+	/* Set pin ctl again, it might have just been set to 0 */
+	snd_hda_set_pin_ctl(codec, nid,
+			    snd_hda_codec_get_pin_target(codec, nid));
+
+	return AC_PWRST_D0;
+}
+
 static void alc269_fixup_hp_mute_led(struct hda_codec *codec,
 				     const struct hda_fixup *fix, int action)
 {
@@ -2978,6 +2995,7 @@
 		spec->mute_led_nid = pin - 0x0a + 0x18;
 		spec->gen.vmaster_mute.hook = alc269_fixup_mic_mute_hook;
 		spec->gen.vmaster_mute_enum = 1;
+		codec->power_filter = led_power_filter;
 		snd_printd("Detected mute LED for %x:%d\n", spec->mute_led_nid,
 			   spec->mute_led_polarity);
 		break;
@@ -2993,6 +3011,7 @@
 		spec->mute_led_nid = 0x18;
 		spec->gen.vmaster_mute.hook = alc269_fixup_mic_mute_hook;
 		spec->gen.vmaster_mute_enum = 1;
+		codec->power_filter = led_power_filter;
 	}
 }
 
@@ -3005,6 +3024,7 @@
 		spec->mute_led_nid = 0x19;
 		spec->gen.vmaster_mute.hook = alc269_fixup_mic_mute_hook;
 		spec->gen.vmaster_mute_enum = 1;
+		codec->power_filter = led_power_filter;
 	}
 }