Index: sys/cam/scsi/scsi_da.c
===================================================================
--- sys/cam/scsi/scsi_da.c
+++ sys/cam/scsi/scsi_da.c
@@ -3729,7 +3729,7 @@
 	struct da_softc *softc;
 	struct disk_params *dp;
 	u_int lbppbe, lalba;
-	int error;
+	int error, updated;
 
 	softc = (struct da_softc *)periph->softc;
 
@@ -3822,15 +3822,27 @@
 		}
 	}
 
-	softc->disk->d_sectorsize = softc->params.secsize;
-	softc->disk->d_mediasize = softc->params.secsize * (off_t)softc->params.sectors;
-	softc->disk->d_stripesize = softc->params.stripesize;
-	softc->disk->d_stripeoffset = softc->params.stripeoffset;
+	/* Set disk params, and send a devctl event if any have changed. */
+#define	_CHECK_UPDATED(dst, src) do {	\
+	updated |= ((src) ^ (dst));	\
+	dst = src;			\
+} while (0)
+	updated = 0;
+	_CHECK_UPDATED(softc->disk->d_sectorsize, softc->params.secsize);
+	_CHECK_UPDATED(softc->disk->d_mediasize,
+	    softc->params.secsize * (off_t)softc->params.sectors);
+	_CHECK_UPDATED(softc->disk->d_stripesize, softc->params.stripesize);
+	_CHECK_UPDATED(softc->disk->d_stripeoffset, softc->params.stripeoffset);
 	/* XXX: these are not actually "firmware" values, so they may be wrong */
-	softc->disk->d_fwsectors = softc->params.secs_per_track;
-	softc->disk->d_fwheads = softc->params.heads;
-	softc->disk->d_devstat->block_size = softc->params.secsize;
-	softc->disk->d_devstat->flags &= ~DEVSTAT_BS_UNAVAILABLE;
+	_CHECK_UPDATED(softc->disk->d_fwsectors, softc->params.secs_per_track);
+	_CHECK_UPDATED(softc->disk->d_fwheads, softc->params.heads);
+	_CHECK_UPDATED(softc->disk->d_devstat->block_size, softc->params.secsize);
+	_CHECK_UPDATED(softc->disk->d_devstat->flags,
+	    softc->disk->d_devstat->flags & ~DEVSTAT_BS_UNAVAILABLE);
+#undef _CHECK_UPDATED
+
+	if (updated != 0)
+		disk_attr_changed(softc->disk, "GEOM::diskparams", M_NOWAIT);
 
 	error = disk_resize(softc->disk, M_NOWAIT);
 	if (error != 0)
Index: sys/geom/geom_disk.c
===================================================================
--- sys/geom/geom_disk.c
+++ sys/geom/geom_disk.c
@@ -43,6 +43,7 @@
 #include <sys/kernel.h>
 #include <sys/sysctl.h>
 #include <sys/bio.h>
+#include <sys/bus.h> /* for devctl_notify() */
 #include <sys/ctype.h>
 #include <sys/fcntl.h>
 #include <sys/malloc.h>
@@ -839,11 +840,14 @@
 {
 	struct g_geom *gp;
 	struct g_provider *pp;
+	char devnamebuf[128];
 
 	gp = dp->d_geom;
 	if (gp != NULL)
 		LIST_FOREACH(pp, &gp->provider, provider)
 			(void)g_attr_changed(pp, attr, flag);
+	snprintf(devnamebuf, 128, "devname=%s%d", dp->d_name, dp->d_unit);
+	devctl_notify("GEOM", "disk", attr, devnamebuf);
 }
 
 void