Index: src/sys/dev/sound/pcm/mixer.c
===================================================================
RCS file: /home/ncvs/src/sys/dev/sound/pcm/mixer.c,v
retrieving revision 1.43.2.3
diff -u -r1.43.2.3 mixer.c
--- src/sys/dev/sound/pcm/mixer.c	30 Dec 2005 19:55:54 -0000	1.43.2.3
+++ src/sys/dev/sound/pcm/mixer.c	4 Apr 2006 14:59:49 -0000
@@ -269,10 +269,14 @@
 mixer_uninit(device_t dev)
 {
 	int i;
+	struct snddev_info *d;
 	struct snd_mixer *m;
 	struct cdev *pdev;
 
+	d = device_get_softc(dev);
 	pdev = mixer_get_devt(dev);
+	if (d == NULL || pdev == NULL || pdev->si_drv1 == NULL)
+		return EBADF;
 	m = pdev->si_drv1;
 	snd_mtxlock(m->lock);
 
@@ -294,6 +298,8 @@
 	snd_mtxfree(m->lock);
 	kobj_delete((kobj_t)m, M_MIXER);
 
+	d->mixer_dev = NULL;
+
 	return 0;
 }
 
@@ -465,10 +471,16 @@
 	int v = -1, j = cmd & 0xff;
 
 	m = i_dev->si_drv1;
-	if (mode != -1 && !m->busy)
+
+	if (m == NULL)
 		return EBADF;
 
 	snd_mtxlock(m->lock);
+	if (mode != -1 && !m->busy) {
+		snd_mtxunlock(m->lock);
+		return EBADF;
+	}
+
 	if ((cmd & MIXER_WRITE(0)) == MIXER_WRITE(0)) {
 		if (j == SOUND_MIXER_RECSRC)
 			ret = mixer_setrecsrc(m, *arg_i);