diff --git a/sys/dev/sound/pcm/channel.c b/sys/dev/sound/pcm/channel.c
index 1ecc31e..4874e67 100644
--- a/sys/dev/sound/pcm/channel.c
+++ b/sys/dev/sound/pcm/channel.c
@@ -472,7 +472,7 @@ chn_wrintr(struct pcm_channel *c)
  */
 
 int
-chn_write(struct pcm_channel *c, struct uio *buf)
+chn_write(struct pcm_channel *c, struct uio *buf, int ioflag)
 {
 	struct snd_dbuf *bs = c->bufsoft;
 	void *off;
@@ -483,6 +483,11 @@ chn_write(struct pcm_channel *c, struct uio *buf)
 	ret = 0;
 	timeout = chn_timeout * hz;
 
+	if (ioflag & O_NONBLOCK)
+		c->flags |= CHN_F_NBIO;
+	else
+		c->flags &= ~CHN_F_NBIO;
+
 	while (ret == 0 && buf->uio_resid > 0) {
 		sz = min(buf->uio_resid, sndbuf_getfree(bs));
 		if (sz > 0) {
@@ -507,7 +512,7 @@ chn_write(struct pcm_channel *c, struct uio *buf)
 				if (ret != 0)
 					c->flags |= CHN_F_DEAD;
 			}
-		} else if (c->flags & (CHN_F_NBIO | CHN_F_NOTRIGGER)) {
+		} else if ((ioflag & O_NONBLOCK) || (c->flags & CHN_F_NOTRIGGER)) {
 			/**
 			 * @todo Evaluate whether EAGAIN is truly desirable.
 			 * 	 4Front drivers behave like this, but I'm
@@ -602,7 +607,7 @@ chn_rdintr(struct pcm_channel *c)
  */
 
 int
-chn_read(struct pcm_channel *c, struct uio *buf)
+chn_read(struct pcm_channel *c, struct uio *buf, int ioflag)
 {
 	struct snd_dbuf *bs = c->bufsoft;
 	void *off;
@@ -610,6 +615,11 @@ chn_read(struct pcm_channel *c, struct uio *buf)
 
 	CHN_LOCKASSERT(c);
 
+	if (ioflag & O_NONBLOCK)
+		c->flags |= CHN_F_NBIO;
+	else
+		c->flags &= ~CHN_F_NBIO;
+
 	if (CHN_STOPPED(c) && !(c->flags & CHN_F_NOTRIGGER)) {
 		ret = chn_start(c, 0);
 		if (ret != 0) {
@@ -640,9 +650,9 @@ chn_read(struct pcm_channel *c, struct uio *buf)
 				sndbuf_dispose(bs, NULL, t);
 			}
 			ret = 0;
-		} else if (c->flags & (CHN_F_NBIO | CHN_F_NOTRIGGER))
+		} else if ((ioflag & O_NONBLOCK) || (c->flags & CHN_F_NOTRIGGER)) {
 			ret = EAGAIN;
-		else {
+		} else {
    			ret = chn_sleep(c, timeout);
 			if (ret == EAGAIN) {
 				ret = EINVAL;
diff --git a/sys/dev/sound/pcm/channel.h b/sys/dev/sound/pcm/channel.h
index dcdc782..c2da759 100644
--- a/sys/dev/sound/pcm/channel.h
+++ b/sys/dev/sound/pcm/channel.h
@@ -254,8 +254,8 @@ struct pcm_channel {
 #include "channel_if.h"
 
 int chn_reinit(struct pcm_channel *c);
-int chn_write(struct pcm_channel *c, struct uio *buf);
-int chn_read(struct pcm_channel *c, struct uio *buf);
+int chn_write(struct pcm_channel *c, struct uio *buf, int ioflag);
+int chn_read(struct pcm_channel *c, struct uio *buf, int ioflag);
 u_int32_t chn_start(struct pcm_channel *c, int force);
 int chn_sync(struct pcm_channel *c, int threshold);
 int chn_flush(struct pcm_channel *c);
diff --git a/sys/dev/sound/pcm/dsp.c b/sys/dev/sound/pcm/dsp.c
index 6677ce4..44c62b6 100644
--- a/sys/dev/sound/pcm/dsp.c
+++ b/sys/dev/sound/pcm/dsp.c
@@ -834,11 +834,11 @@ dsp_close(struct dev_close_args *ap)
 }
 
 static __inline int
-dsp_io_ops(struct cdev *i_dev, struct uio *buf)
+dsp_io_ops(struct cdev *i_dev, struct uio *buf, int ioflag)
 {
 	struct snddev_info *d;
 	struct pcm_channel **ch, *rdch, *wrch;
-	int (*chn_io)(struct pcm_channel *, struct uio *);
+	int (*chn_io)(struct pcm_channel *, struct uio *, int);
 	int prio, ret;
 	pid_t runpid;
 
@@ -895,7 +895,7 @@ dsp_io_ops(struct cdev *i_dev, struct uio *buf)
 	 * someone else doesn't come along and muss up the buffer.
 	 */
 	++(*ch)->inprog;
-	ret = chn_io(*ch, buf);
+	ret = chn_io(*ch, buf, ioflag);
 	--(*ch)->inprog;
 
 	CHN_BROADCAST(&(*ch)->cv);
@@ -913,7 +913,7 @@ dsp_read(struct dev_read_args *ap)
 	struct cdev *i_dev = ap->a_head.a_dev;
 	struct uio *buf = ap->a_uio;
 
-	return (dsp_io_ops(i_dev, buf));
+	return (dsp_io_ops(i_dev, buf, ap->a_ioflag));
 }
 
 static int
@@ -922,7 +922,7 @@ dsp_write(struct dev_write_args *ap)
 	struct cdev *i_dev = ap->a_head.a_dev;
 	struct uio *buf = ap->a_uio;
 
-	return (dsp_io_ops(i_dev, buf));
+	return (dsp_io_ops(i_dev, buf, ap->a_ioflag));
 }
 
 static int