From 302d5a80d232134246032bc4263fd7facdddb8f1 Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@suse.de>
Date: Tue, 29 Oct 2019 21:41:20 +0100
Subject: [PATCH] ALSA: hda - Fix mutex deadlock in HDMI codec driver
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Git-commit: 302d5a80d232134246032bc4263fd7facdddb8f1
Patch-mainline: v5.4-rc6
References: git-fixes

The commit ade49db337a9 ("ALSA: hda/hdmi - Allow audio component for
AMD/ATI and Nvidia HDMI") introduced the spec->pcm_lock mutex lock to
the whole generic_hdmi_init() function for avoiding the race with the
audio component registration.  However, this caused a dead lock when
the unsolicited event is handled without the audio component, as the
codec gets runtime-resumed in hdmi_present_sense() which is already
inside the spec->pcm_lock in its caller.

For avoiding this deadlock, add a new mutex only for the audio
component binding that is used in both generic_hdmi_init() and the
audio notifier registration where the jack callbacks are handled /
re-registered.

Fixes: ade49db337a9 ("ALSA: hda/hdmi - Allow audio component for AMD/ATI and Nvidia HDMI")
Reported-and-tested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://lore.kernel.org/r/s5himo7i89i.wl-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

---
 sound/pci/hda/patch_hdmi.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/sound/pci/hda/patch_hdmi.c b/sound/pci/hda/patch_hdmi.c
index 795cbda32cbb..b72553710ffb 100644
--- a/sound/pci/hda/patch_hdmi.c
+++ b/sound/pci/hda/patch_hdmi.c
@@ -145,6 +145,7 @@ struct hdmi_spec {
 	struct snd_array pins; /* struct hdmi_spec_per_pin */
 	struct hdmi_pcm pcm_rec[16];
 	struct mutex pcm_lock;
+	struct mutex bind_lock; /* for audio component binding */
 	/* pcm_bitmap means which pcms have been assigned to pins*/
 	unsigned long pcm_bitmap;
 	int pcm_used;	/* counter of pcm_rec[] */
@@ -2258,7 +2259,7 @@ static int generic_hdmi_init(struct hda_codec *codec)
 	struct hdmi_spec *spec = codec->spec;
 	int pin_idx;
 
-	mutex_lock(&spec->pcm_lock);
+	mutex_lock(&spec->bind_lock);
 	spec->use_jack_detect = !codec->jackpoll_interval;
 	for (pin_idx = 0; pin_idx < spec->num_pins; pin_idx++) {
 		struct hdmi_spec_per_pin *per_pin = get_pin(spec, pin_idx);
@@ -2275,7 +2276,7 @@ static int generic_hdmi_init(struct hda_codec *codec)
 			snd_hda_jack_detect_enable_callback(codec, pin_nid,
 							    jack_callback);
 	}
-	mutex_unlock(&spec->pcm_lock);
+	mutex_unlock(&spec->bind_lock);
 	return 0;
 }
 
@@ -2382,6 +2383,7 @@ static int alloc_generic_hdmi(struct hda_codec *codec)
 	spec->ops = generic_standard_hdmi_ops;
 	spec->dev_num = 1;	/* initialize to 1 */
 	mutex_init(&spec->pcm_lock);
+	mutex_init(&spec->bind_lock);
 	snd_hdac_register_chmap_ops(&codec->core, &spec->chmap);
 
 	spec->chmap.ops.get_chmap = hdmi_get_chmap;
@@ -2451,7 +2453,7 @@ static void generic_acomp_notifier_set(struct drm_audio_component *acomp,
 	int i;
 
 	spec = container_of(acomp->audio_ops, struct hdmi_spec, drm_audio_ops);
-	mutex_lock(&spec->pcm_lock);
+	mutex_lock(&spec->bind_lock);
 	spec->use_acomp_notifier = use_acomp;
 	spec->codec->relaxed_resume = use_acomp;
 	/* reprogram each jack detection logic depending on the notifier */
@@ -2461,7 +2463,7 @@ static void generic_acomp_notifier_set(struct drm_audio_component *acomp,
 					      get_pin(spec, i)->pin_nid,
 					      use_acomp);
 	}
-	mutex_unlock(&spec->pcm_lock);
+	mutex_unlock(&spec->bind_lock);
 }
 
 /* enable / disable the notifier via master bind / unbind */
-- 
2.16.4