Index: sys/conf/options
===================================================================
--- sys/conf/options
+++ sys/conf/options
@@ -178,6 +178,7 @@
 NO_ADAPTIVE_RWLOCKS
 NO_ADAPTIVE_SX
 NO_EVENTTIMERS		opt_timer.h
+NO_OBSOLETE_CODE	opt_global.h
 NO_SYSCTL_DESCR	opt_global.h
 NSWBUF_MIN	opt_swap.h
 MBUF_PACKET_ZONE_DISABLE	opt_global.h
Index: sys/dev/advansys/advansys.c
===================================================================
--- sys/dev/advansys/advansys.c
+++ sys/dev/advansys/advansys.c
@@ -1399,6 +1399,8 @@
 	csa.callback_arg = adv;
 	xpt_action((union ccb *)&csa);
 	mtx_unlock(&adv->lock);
+	gone_in_dev(adv->adv, 12, "adv(4) driver");
+
 	return (0);
 }
 MODULE_DEPEND(adv, cam, 1, 1, 1);
Index: sys/dev/advansys/adwcam.c
===================================================================
--- sys/dev/advansys/adwcam.c
+++ sys/dev/advansys/adwcam.c
@@ -1173,6 +1173,7 @@
 		xpt_action((union ccb *)&csa);
 	}
 
+	gone_in_dev(adv->adv, 12, "adw(4) driver");
 fail:
 	mtx_unlock(&adw->lock);
 	return (error);
Index: sys/dev/aha/aha.c
===================================================================
--- sys/dev/aha/aha.c
+++ sys/dev/aha/aha.c
@@ -620,6 +620,7 @@
 		return (ENXIO);
 	}
 	mtx_unlock(&aha->lock);
+	gone_in_dev(aha->dev, 12, "aha(4) driver");
 
 	return (0);
 }
Index: sys/dev/aic/aic.c
===================================================================
--- sys/dev/aic/aic.c
+++ sys/dev/aic/aic.c
@@ -1577,6 +1577,7 @@
 		printf(", fast SCSI");
 	printf("\n");
 	mtx_unlock(&aic->lock);
+	gone_in_dev(aic->dev, 12, "aic(4) driver");
 	return (0);
 }
 
Index: sys/dev/buslogic/bt.c
===================================================================
--- sys/dev/buslogic/bt.c
+++ sys/dev/buslogic/bt.c
@@ -905,6 +905,7 @@
 		device_printf(dev, "bus_setup_intr() failed: %d\n", error);
 		return (error);
 	}
+	gone_in_dev(dev, 12, "bt(4) driver");
 
 	return (0);
 }
Index: sys/dev/dpt/dpt_pci.c
===================================================================
--- sys/dev/dpt/dpt_pci.c
+++ sys/dev/dpt/dpt_pci.c
@@ -157,6 +157,7 @@
 		error = ENXIO;
 		goto bad;
 	}
+	gone_in_dev(dev, 12, "dpt(4) driver");
 
 	return (error);
 
Index: sys/dev/joy/joy.c
===================================================================
--- sys/dev/joy/joy.c
+++ sys/dev/joy/joy.c
@@ -110,6 +110,8 @@
 	joy->timeout[0] = joy->timeout[1] = 0;
 	joy->d = make_dev(&joy_cdevsw, unit, 0, 0, 0600, "joy%d", unit);
 	joy->d->si_drv1 = joy;
+	gone_in_dev(dev, 12, "joy(4) driver");
+
 	return (0);
 }
 
Index: sys/dev/mse/mse.c
===================================================================
--- sys/dev/mse/mse.c
+++ sys/dev/mse/mse.c
@@ -153,6 +153,8 @@
 	sc->sc_ndev = make_dev(&mse_cdevsw, 1, UID_ROOT, GID_WHEEL, 0600,
 	    "nmse%d", unit);
 	sc->sc_ndev->si_drv1 = sc;
+	gone_in_dev(dev, 12, "mse(4) driver");
+
 	return 0;
 }
 
Index: sys/dev/ncv/ncr53c500_pccard.c
===================================================================
--- sys/dev/ncv/ncr53c500_pccard.c
+++ sys/dev/ncv/ncr53c500_pccard.c
@@ -263,6 +263,7 @@
 		ncv_release_resource(dev);
 		return(ENXIO);
 	}
+	gone_in_dev(dev, 12, "ncv(4) driver");
 
 	return(0);
 }
Index: sys/dev/nsp/nsp_pccard.c
===================================================================
--- sys/dev/nsp/nsp_pccard.c
+++ sys/dev/nsp/nsp_pccard.c
@@ -205,6 +205,7 @@
 		nsp_release_resource(dev);
 		return(ENXIO);
 	}
+	gone_in_dev(dev, 12, "nsp(4) driver");
 
 	return(0);
 }
Index: sys/dev/stg/tmc18c30.c
===================================================================
--- sys/dev/stg/tmc18c30.c
+++ sys/dev/stg/tmc18c30.c
@@ -423,6 +423,7 @@
 
 	(void) scsi_low_attach(slp, 0, STG_NTARGETS, STG_NLUNS,
 				sizeof(struct stg_targ_info), 0);
+	gone_in(12, "stg(4) driver");
 }
 
 /**************************************************************
Index: sys/kern/subr_bus.c
===================================================================
--- sys/kern/subr_bus.c
+++ sys/kern/subr_bus.c
@@ -5604,6 +5604,54 @@
 	    UID_ROOT, GID_WHEEL, 0600, "devctl2");
 }
 
+/*
+ * Obsolete management stuff.
+ */
+static int obsolete_panic = 0;
+/* 0 - don't panic, 1 - panic if already obsolete, 2 - panic if deprecated */
+static void
+gone_panic(int major, int running, const char *msg)
+{
+
+	switch (obsolete_panic)
+	{
+	case 0:
+		return;
+	case 1:
+		if (running < major)
+			return;
+		/* FALLTHROUGH */
+	default:
+		panic("%s", msg);
+	}
+}
+
+void
+_gone_in(int major, const char *msg)
+{
+
+	gone_panic(major, P_OSREL_MAJOR(__FreeBSD_version), msg);
+	if (P_OSREL_MAJOR(__FreeBSD_version) >= major)
+		printf("Obsolete code will removed soon: %s\n", msg);
+	else if (P_OSREL_MAJOR(__FreeBSD_version) + 1 == major)
+		printf("Deprecated code (to be removed in FreeBSD %d): %s\n",
+		    major, msg);
+}
+
+void
+_gone_in_dev(device_t dev, int major, const char *msg)
+{
+
+	gone_panic(major, P_OSREL_MAJOR(__FreeBSD_version), msg);
+	if (P_OSREL_MAJOR(__FreeBSD_version) >= major)
+		device_printf(dev,
+		    "Obsolete code will removed soon: %s\n", msg);
+	else if (P_OSREL_MAJOR(__FreeBSD_version) + 1 == major)
+		device_printf(dev,
+		    "Deprecated code (to be removed in FreeBSD %d): %s\n",
+		    major, msg);
+}
+
 #ifdef DDB
 DB_SHOW_COMMAND(device, db_show_device)
 {
Index: sys/sys/systm.h
===================================================================
--- sys/sys/systm.h
+++ sys/sys/systm.h
@@ -464,6 +464,22 @@
 
 void counted_warning(unsigned *counter, const char *msg);
 
+/*
+ * APIs to manage deprecation and obsolescence.
+ */
+struct device;
+void _gone_in(int major, const char *msg);
+void _gone_in_dev(struct device *dev, int major, const char *msg);
+#ifdef NO_OBSOLETE_CODE
+#define __gone_ok(m, msg)					 \
+	_Static_assert(m < P_OSREL_MAJOR(__FreeBSD_version)),	 \
+	    "Obsolete code" msg);
+#else
+#define	__gone_ok(m, msg)
+#endif
+#define gone_in(major, msg)		__gone_ok(major, msg) _gone_in(major, msg)
+#define gone_in_dev(dev, major, msg)	__gone_ok(major, msg) _gone_in_dev(dev, major, msg)
+
 __NULLABILITY_PRAGMA_POP
 
 #endif /* !_SYS_SYSTM_H_ */