linux-kernel - [PATCH 3.16 371/410] ALSA: hda/realtek - Always immediately update mute LED with pin VREF

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Message-ID: <lsq.1528380321.949954103@decadent.org.uk>
Date:   Thu, 07 Jun 2018 15:05:21 +0100
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org, "Takashi Iwai" <tiwai@...e.de>
Subject: [PATCH 3.16 371/410] ALSA: hda/realtek - Always immediately
 update mute LED with pin VREF

3.16.57-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Takashi Iwai <tiwai@...e.de>

commit e40bdb03d3cd7da66bd0bc1e40cbcfb49351265c upstream.

Some HP laptops have a mute mute LED controlled by a pin VREF.  The
Realtek codec driver updates the VREF via vmaster hook by calling
snd_hda_set_pin_ctl_cache().

This works fine as long as the driver is running in a normal mode.
However, when the VREF change happens during the codec being in
runtime PM suspend, the regmap access will skip and postpone the
actual register change.  This ends up with the unchanged LED status
until the next runtime PM resume even if you change the Master mute
switch.  (Interestingly, the machine keeps the LED status even after
the codec goes into D3 -- but it's another story.)

For improving this usability, let the driver temporarily powering up /
down only during the pin VREF change.  This can be achieved easily by
wrapping the call with snd_hda_power_up_pm() / *_down_pm().

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=199073
Signed-off-by: Takashi Iwai <tiwai@...e.de>
[bwh: Backported to 3.16: Use snd_hda_power{down,up}() (without the _pm
 suffix]
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 sound/pci/hda/patch_realtek.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

--- a/sound/pci/hda/patch_realtek.c
+++ b/sound/pci/hda/patch_realtek.c
@@ -3435,8 +3435,12 @@ static void alc269_fixup_mic_mute_hook(v
 	pinval = snd_hda_codec_get_pin_target(codec, spec->mute_led_nid);
 	pinval &= ~AC_PINCTL_VREFEN;
 	pinval |= enabled ? AC_PINCTL_VREF_HIZ : AC_PINCTL_VREF_80;
-	if (spec->mute_led_nid)
+	if (spec->mute_led_nid) {
+		/* temporarily power up/down for setting VREF */
+		snd_hda_power_up(codec);
 		snd_hda_set_pin_ctl_cache(codec, spec->mute_led_nid, pinval);
+		snd_hda_power_down(codec);
+	}
 }

 /* Make sure the led works even in runtime suspend */