diff --git a/Documentation/sound/kernel-api/writing-an-alsa-driver.rst b/Documentation/sound/kernel-api/writing-an-alsa-driver.rst
index a368529e8ed3..e37d9dba320d 100644
--- a/Documentation/sound/kernel-api/writing-an-alsa-driver.rst
+++ b/Documentation/sound/kernel-api/writing-an-alsa-driver.rst
@@ -1577,14 +1577,19 @@ are the contents of this file:
           unsigned int period_step;
           unsigned int sleep_min;		/* min ticks to sleep */
           snd_pcm_uframes_t start_threshold;
-          snd_pcm_uframes_t stop_threshold;
-          snd_pcm_uframes_t silence_threshold; /* Silence filling happens when
-                                                  noise is nearest than this */
-          snd_pcm_uframes_t silence_size;	/* Silence filling size */
+          /*
+           * The following two thresholds alleviate playback buffer underruns; when
+           * hw_avail drops below the threshold, the respective action is triggered:
+           */
+          snd_pcm_uframes_t stop_threshold;	/* - stop playback */
+          snd_pcm_uframes_t silence_threshold;	/* - pre-fill buffer with silence */
+          snd_pcm_uframes_t silence_size;       /* max size of silence pre-fill; when >= boundary,
+                                                 * fill played area with silence immediately */
           snd_pcm_uframes_t boundary;	/* pointers wrap point */
   
-          snd_pcm_uframes_t silenced_start;
-          snd_pcm_uframes_t silenced_size;
+          /* internal data of auto-silencer */
+          snd_pcm_uframes_t silence_start; /* starting pointer to silence area */
+          snd_pcm_uframes_t silence_filled; /* size filled with silence */
   
           snd_pcm_sync_id_t sync;		/* hardware synchronization ID */
   
diff --git a/include/sound/pcm.h b/include/sound/pcm.h
index 27040b472a4f..19f564606ac4 100644
--- a/include/sound/pcm.h
+++ b/include/sound/pcm.h
@@ -378,18 +378,18 @@ struct snd_pcm_runtime {
 	unsigned int rate_den;
 	unsigned int no_period_wakeup: 1;
 
-	/* -- SW params -- */
-	int tstamp_mode;		/* mmap timestamp is updated */
+	/* -- SW params; see struct snd_pcm_sw_params for comments -- */
+	int tstamp_mode;
   	unsigned int period_step;
 	snd_pcm_uframes_t start_threshold;
 	snd_pcm_uframes_t stop_threshold;
-	snd_pcm_uframes_t silence_threshold; /* Silence filling happens when
-						noise is nearest than this */
-	snd_pcm_uframes_t silence_size;	/* Silence filling size */
-	snd_pcm_uframes_t boundary;	/* pointers wrap point */
+	snd_pcm_uframes_t silence_threshold;
+	snd_pcm_uframes_t silence_size;
+	snd_pcm_uframes_t boundary;
 
+	/* internal data of auto-silencer */
 	snd_pcm_uframes_t silence_start; /* starting pointer to silence area */
-	snd_pcm_uframes_t silence_filled; /* size filled with silence */
+	snd_pcm_uframes_t silence_filled; /* already filled part of silence area */
 
 	union snd_pcm_sync_id sync;	/* hardware synchronization ID */
 
diff --git a/include/uapi/sound/asound.h b/include/uapi/sound/asound.h
index 7eecc99ddef7..0aa955aa8246 100644
--- a/include/uapi/sound/asound.h
+++ b/include/uapi/sound/asound.h
@@ -429,9 +429,14 @@ struct snd_pcm_sw_params {
 	snd_pcm_uframes_t avail_min;		/* min avail frames for wakeup */
 	snd_pcm_uframes_t xfer_align;		/* obsolete: xfer size need to be a multiple */
 	snd_pcm_uframes_t start_threshold;	/* min hw_avail frames for automatic start */
-	snd_pcm_uframes_t stop_threshold;	/* min avail frames for automatic stop */
-	snd_pcm_uframes_t silence_threshold;	/* min distance from noise for silence filling */
-	snd_pcm_uframes_t silence_size;		/* silence block size */
+	/*
+	 * The following two thresholds alleviate playback buffer underruns; when
+	 * hw_avail drops below the threshold, the respective action is triggered:
+	 */
+	snd_pcm_uframes_t stop_threshold;	/* - stop playback */
+	snd_pcm_uframes_t silence_threshold;	/* - pre-fill buffer with silence */
+	snd_pcm_uframes_t silence_size;		/* max size of silence pre-fill; when >= boundary,
+						 * fill played area with silence immediately */
 	snd_pcm_uframes_t boundary;		/* pointers wrap point */
 	unsigned int proto;			/* protocol version */
 	unsigned int tstamp_type;		/* timestamp type (req. proto >= 2.0.12) */
diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c
index af1eb136feb0..d21c73944efd 100644
--- a/sound/core/pcm_lib.c
+++ b/sound/core/pcm_lib.c
@@ -42,70 +42,56 @@ static int fill_silence_frames(struct snd_pcm_substream *substream,
  *
  * when runtime->silence_size >= runtime->boundary - fill processed area with silence immediately
  */
-void snd_pcm_playback_silence(struct snd_pcm_substream *substream, snd_pcm_uframes_t new_hw_ptr)
+void snd_pcm_playback_silence(struct snd_pcm_substream *substream)
 {
 	struct snd_pcm_runtime *runtime = substream->runtime;
-	snd_pcm_uframes_t frames, ofs, transfer;
+	snd_pcm_uframes_t appl_ptr = READ_ONCE(runtime->control->appl_ptr);
+	snd_pcm_sframes_t added, hw_avail, frames;
+	snd_pcm_uframes_t noise_dist, ofs, transfer;
 	int err;
 
+	added = appl_ptr - runtime->silence_start;
+	if (added) {
+		if (added < 0)
+			added += runtime->boundary;
+		if (added < runtime->silence_filled)
+			runtime->silence_filled -= added;
+		else
+			runtime->silence_filled = 0;
+		runtime->silence_start = appl_ptr;
+	}
+
+	// This will "legitimately" turn negative on underrun, and will be mangled
+	// into a huge number by the boundary crossing handling. The initial state
+	// might also be not quite sane. The code below MUST account for these cases.
+	hw_avail = appl_ptr - runtime->status->hw_ptr;
+	if (hw_avail < 0)
+		hw_avail += runtime->boundary;
+
+	noise_dist = hw_avail + runtime->silence_filled;
 	if (runtime->silence_size < runtime->boundary) {
-		snd_pcm_sframes_t noise_dist, n;
-		snd_pcm_uframes_t appl_ptr = READ_ONCE(runtime->control->appl_ptr);
-		if (runtime->silence_start != appl_ptr) {
-			n = appl_ptr - runtime->silence_start;
-			if (n < 0)
-				n += runtime->boundary;
-			if ((snd_pcm_uframes_t)n < runtime->silence_filled)
-				runtime->silence_filled -= n;
-			else
-				runtime->silence_filled = 0;
-			runtime->silence_start = appl_ptr;
-		}
-		if (runtime->silence_filled >= runtime->buffer_size)
-			return;
-		noise_dist = snd_pcm_playback_hw_avail(runtime) + runtime->silence_filled;
-		if (noise_dist >= (snd_pcm_sframes_t) runtime->silence_threshold)
-			return;
 		frames = runtime->silence_threshold - noise_dist;
+		if (frames <= 0)
+			return;
 		if (frames > runtime->silence_size)
 			frames = runtime->silence_size;
 	} else {
-		if (new_hw_ptr == ULONG_MAX) {	/* initialization */
-			snd_pcm_sframes_t avail = snd_pcm_playback_hw_avail(runtime);
-			if (avail > runtime->buffer_size)
-				avail = runtime->buffer_size;
-			runtime->silence_filled = avail > 0 ? avail : 0;
-			runtime->silence_start = (runtime->status->hw_ptr +
-						  runtime->silence_filled) %
-						 runtime->boundary;
-		} else {
-			ofs = runtime->status->hw_ptr;
-			frames = new_hw_ptr - ofs;
-			if ((snd_pcm_sframes_t)frames < 0)
-				frames += runtime->boundary;
-			runtime->silence_filled -= frames;
-			if ((snd_pcm_sframes_t)runtime->silence_filled < 0) {
-				runtime->silence_filled = 0;
-				runtime->silence_start = new_hw_ptr;
-			} else {
-				runtime->silence_start = ofs;
-			}
-		}
-		frames = runtime->buffer_size - runtime->silence_filled;
+		frames = runtime->buffer_size - noise_dist;
+		if (frames <= 0)
+			return;
 	}
+
 	if (snd_BUG_ON(frames > runtime->buffer_size))
 		return;
-	if (frames == 0)
-		return;
-	ofs = runtime->silence_start % runtime->buffer_size;
-	while (frames > 0) {
+	ofs = (runtime->silence_start + runtime->silence_filled) % runtime->buffer_size;
+	do {
 		transfer = ofs + frames > runtime->buffer_size ? runtime->buffer_size - ofs : frames;
 		err = fill_silence_frames(substream, ofs, transfer);
 		snd_BUG_ON(err < 0);
 		runtime->silence_filled += transfer;
 		frames -= transfer;
 		ofs = 0;
-	}
+	} while (frames > 0);
 	snd_pcm_dma_buffer_sync(substream, SNDRV_DMA_SYNC_DEVICE);
 }
 
@@ -439,10 +425,6 @@ static int snd_pcm_update_hw_ptr0(struct snd_pcm_substream *substream,
 		return 0;
 	}
 
-	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK &&
-	    runtime->silence_size > 0)
-		snd_pcm_playback_silence(substream, new_hw_ptr);
-
 	if (in_interrupt) {
 		delta = new_hw_ptr - runtime->hw_ptr_interrupt;
 		if (delta < 0)
@@ -460,6 +442,10 @@ static int snd_pcm_update_hw_ptr0(struct snd_pcm_substream *substream,
 		runtime->hw_ptr_wrap += runtime->boundary;
 	}
 
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK &&
+	    runtime->silence_size > 0)
+		snd_pcm_playback_silence(substream);
+
 	update_audio_tstamp(substream, &curr_tstamp, &audio_tstamp);
 
 	return snd_pcm_update_state(substream, runtime);
diff --git a/sound/core/pcm_local.h b/sound/core/pcm_local.h
index ecb21697ae3a..42fe3a4e9154 100644
--- a/sound/core/pcm_local.h
+++ b/sound/core/pcm_local.h
@@ -29,8 +29,7 @@ int snd_pcm_update_state(struct snd_pcm_substream *substream,
 			 struct snd_pcm_runtime *runtime);
 int snd_pcm_update_hw_ptr(struct snd_pcm_substream *substream);
 
-void snd_pcm_playback_silence(struct snd_pcm_substream *substream,
-			      snd_pcm_uframes_t new_hw_ptr);
+void snd_pcm_playback_silence(struct snd_pcm_substream *substream);
 
 static inline snd_pcm_uframes_t
 snd_pcm_avail(struct snd_pcm_substream *substream)
diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index 94185267a7b9..3d0c4a5b701b 100644
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -958,7 +958,7 @@ static int snd_pcm_sw_params(struct snd_pcm_substream *substream,
 	if (snd_pcm_running(substream)) {
 		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK &&
 		    runtime->silence_size > 0)
-			snd_pcm_playback_silence(substream, ULONG_MAX);
+			snd_pcm_playback_silence(substream);
 		err = snd_pcm_update_state(substream, runtime);
 	}
 	snd_pcm_stream_unlock_irq(substream);
@@ -1455,7 +1455,7 @@ static void snd_pcm_post_start(struct snd_pcm_substream *substream,
 	__snd_pcm_set_state(runtime, state);
 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK &&
 	    runtime->silence_size > 0)
-		snd_pcm_playback_silence(substream, ULONG_MAX);
+		snd_pcm_playback_silence(substream);
 	snd_pcm_timer_notify(substream, SNDRV_TIMER_EVENT_MSTART);
 }
 
@@ -1916,7 +1916,7 @@ static void snd_pcm_post_reset(struct snd_pcm_substream *substream,
 	runtime->control->appl_ptr = runtime->status->hw_ptr;
 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK &&
 	    runtime->silence_size > 0)
-		snd_pcm_playback_silence(substream, ULONG_MAX);
+		snd_pcm_playback_silence(substream);
 	snd_pcm_stream_unlock_irq(substream);
 }