diff --git a/axfer/xfer-libasound-irq-mmap.c b/axfer/xfer-libasound-irq-mmap.c
index 87ef7e0..18f6dfe 100644
--- a/axfer/xfer-libasound-irq-mmap.c
+++ b/axfer/xfer-libasound-irq-mmap.c
@@ -81,10 +81,12 @@ static int irq_mmap_process_frames(struct libasound_state *state,
 	snd_pcm_sframes_t consumed_count;
 	int err;
 
-	// Wait for hardware IRQ when no avail space in buffer.
-	err = snd_pcm_wait(state->handle, -1);
-	if (err < 0)
-		return err;
+	if (state->use_waiter) {
+		// Wait for hardware IRQ when no avail space in buffer.
+		err = snd_pcm_wait(state->handle, -1);
+		if (err < 0)
+			return err;
+	}
 
 	// Sync cache in user space to data in kernel space to calculate avail
 	// frames according to the latest positions on PCM buffer.
diff --git a/axfer/xfer-libasound-irq-rw.c b/axfer/xfer-libasound-irq-rw.c
index f05ac4b..625c095 100644
--- a/axfer/xfer-libasound-irq-rw.c
+++ b/axfer/xfer-libasound-irq-rw.c
@@ -133,10 +133,12 @@ static int r_process_frames_nonblocking(struct libasound_state *state,
 			goto error;
 	}
 
-	// Wait for hardware IRQ when no available space.
-	err = snd_pcm_wait(state->handle, -1);
-	if (err < 0)
-		goto error;
+	if (state->use_waiter) {
+		// Wait for hardware IRQ when no available space.
+		err = snd_pcm_wait(state->handle, -1);
+		if (err < 0)
+			goto error;
+	}
 
 	// Check available space on the buffer.
 	avail = snd_pcm_avail(state->handle);
@@ -286,10 +288,12 @@ static int w_process_frames_nonblocking(struct libasound_state *state,
 	unsigned int avail_count;
 	int err;
 
-	// Wait for hardware IRQ when no left space.
-	err = snd_pcm_wait(state->handle, -1);
-	if (err < 0)
-		goto error;
+	if (state->use_waiter) {
+		// Wait for hardware IRQ when no left space.
+		err = snd_pcm_wait(state->handle, -1);
+		if (err < 0)
+			goto error;
+	}
 
 	// Check available space on the buffer.
 	avail = snd_pcm_avail(state->handle);
diff --git a/axfer/xfer-libasound.c b/axfer/xfer-libasound.c
index c2e1282..61ae115 100644
--- a/axfer/xfer-libasound.c
+++ b/axfer/xfer-libasound.c
@@ -12,6 +12,7 @@
 enum no_short_opts {
         // 200 or later belong to non us-ascii character set.
 	OPT_FATAL_ERRORS = 200,
+	OPT_TEST_NOWAIT,
 };
 
 #define S_OPTS	"D:NM"
@@ -21,6 +22,7 @@ static const struct option l_opts[] = {
 	{"mmap",		0, 0, 'M'},
 	// For debugging.
 	{"fatal-errors",	0, 0, OPT_FATAL_ERRORS},
+	{"test-nowait",		0, 0, OPT_TEST_NOWAIT},
 };
 
 static int xfer_libasound_init(struct xfer_context *xfer,
@@ -54,6 +56,8 @@ static int xfer_libasound_parse_opt(struct xfer_context *xfer, int key,
 		state->mmap = true;
 	else if (key == OPT_FATAL_ERRORS)
 		state->finish_at_xrun = true;
+	else if (key == OPT_TEST_NOWAIT)
+		state->test_nowait = true;
 	else
 		err = -ENXIO;
 
@@ -80,6 +84,15 @@ int xfer_libasound_validate_opts(struct xfer_context *xfer)
 		return -EINVAL;
 	}
 
+	if (state->test_nowait) {
+		if (!state->nonblock && !state->mmap) {
+			fprintf(stderr,
+				"An option for nowait test should be used with "
+				"nonblock or mmap options.\n");
+			return -EINVAL;
+		}
+	}
+
 	return err;
 }
 
@@ -124,6 +137,9 @@ static int open_handle(struct xfer_context *xfer)
 		return err;
 	}
 
+	if ((state->nonblock || state->mmap) && !state->test_nowait)
+		state->use_waiter = true;
+
 	err = snd_pcm_hw_params_any(state->handle, state->hw_params);
 	if (err < 0)
 		return err;
diff --git a/axfer/xfer-libasound.h b/axfer/xfer-libasound.h
index 550b1c2..f3ce73f 100644
--- a/axfer/xfer-libasound.h
+++ b/axfer/xfer-libasound.h
@@ -33,6 +33,9 @@ struct libasound_state {
 	bool finish_at_xrun:1;
 	bool nonblock:1;
 	bool mmap:1;
+	bool test_nowait:1;
+
+	bool use_waiter:1;
 };
 
 // For internal use in 'libasound' module.