diff --git a/sys/dev/adb/adb_kbd.c b/sys/dev/adb/adb_kbd.c
--- a/sys/dev/adb/adb_kbd.c
+++ b/sys/dev/adb/adb_kbd.c
@@ -798,6 +798,7 @@
 	case OPIO_KEYMAP:
 	case PIO_KEYMAPENT:
 	case PIO_DEADKEYMAP:
+	case OPIO_DEADKEYMAP:
 	default:
 		return (genkbd_commonioctl(kbd, cmd, data));
 	}
diff --git a/sys/dev/atkbdc/atkbd.c b/sys/dev/atkbdc/atkbd.c
--- a/sys/dev/atkbdc/atkbd.c
+++ b/sys/dev/atkbdc/atkbd.c
@@ -1091,6 +1091,7 @@
 	case OPIO_KEYMAP:	/* set keyboard translation table (compat) */
 	case PIO_KEYMAPENT:	/* set keyboard translation table entry */
 	case PIO_DEADKEYMAP:	/* set accent key translation table */
+	case OPIO_DEADKEYMAP:	/* set accent key translation table (compat) */
 		state->ks_accents = 0;
 		/* FALLTHROUGH */
 	default:
diff --git a/sys/dev/gpio/gpiokeys.c b/sys/dev/gpio/gpiokeys.c
--- a/sys/dev/gpio/gpiokeys.c
+++ b/sys/dev/gpio/gpiokeys.c
@@ -899,6 +899,7 @@
 	case PIO_KEYMAPENT:		/* set keyboard translation table
 					 * entry */
 	case PIO_DEADKEYMAP:		/* set accent key translation table */
+	case OPIO_DEADKEYMAP:		/* set accent key translation table (compat) */
 		sc->sc_accents = 0;
 		/* FALLTHROUGH */
 	default:
diff --git a/sys/dev/hid/hkbd.c b/sys/dev/hid/hkbd.c
--- a/sys/dev/hid/hkbd.c
+++ b/sys/dev/hid/hkbd.c
@@ -1640,6 +1640,7 @@
 	case PIO_KEYMAPENT:		/* set keyboard translation table
 					 * entry */
 	case PIO_DEADKEYMAP:		/* set accent key translation table */
+	case OPIO_DEADKEYMAP:		/* set accent key translation table (compat) */
 		sc->sc_accents = 0;
 		/* FALLTHROUGH */
 	default:
diff --git a/sys/dev/hyperv/input/hv_kbd.c b/sys/dev/hyperv/input/hv_kbd.c
--- a/sys/dev/hyperv/input/hv_kbd.c
+++ b/sys/dev/hyperv/input/hv_kbd.c
@@ -666,6 +666,7 @@
 	case OPIO_KEYMAP:	/* set keyboard translation table (compat) */
 	case PIO_KEYMAPENT:	/* set keyboard translation table entry */
 	case PIO_DEADKEYMAP:	/* set accent key translation table */
+	case OPIO_DEADKEYMAP:	/* set accent key translation table (compat) */
 		sc->sc_accents = 0;
 		/* FALLTHROUGH */
 	default:
diff --git a/sys/dev/kbd/kbd.c b/sys/dev/kbd/kbd.c
--- a/sys/dev/kbd/kbd.c
+++ b/sys/dev/kbd/kbd.c
@@ -790,6 +790,8 @@
 {
 	keymap_t *mapp;
 	okeymap_t *omapp;
+	accentmap_t *accentmapp;
+	oaccentmap_t *oaccentmapp;
 	keyarg_t *keyp;
 	fkeyarg_t *fkeyp;
 	int i, j;
@@ -898,16 +900,58 @@
 #endif
 
 	case GIO_DEADKEYMAP:	/* get accent key translation table */
-		bcopy(kbd->kb_accentmap, arg, sizeof(*kbd->kb_accentmap));
+		error = copyout(kbd->kb_accentmap, *(void **)arg,
+		    sizeof(accentmap_t));
+		return (error);
+		break;
+	case OGIO_DEADKEYMAP:	/* get accent key translation table (compat) */
+		accentmapp = kbd->kb_accentmap;
+		oaccentmapp = (oaccentmap_t *)arg;
+		oaccentmapp->n_accs = accentmapp->n_accs;
+		for (i = 0; i < NUM_DEADKEYS; i++) {
+			oaccentmapp->acc[i].accchar =
+			    accentmapp->acc[i].accchar;
+			for (j = 0; j < NUM_ACCENTCHARS; j++) {
+				oaccentmapp->acc[i].map[j][0] =
+				    accentmapp->acc[i].map[j][0];
+				oaccentmapp->acc[i].map[j][1] =
+				    accentmapp->acc[i].map[j][1];
+			}
+		}
 		break;
+
 	case PIO_DEADKEYMAP:	/* set accent key translation table */
+	case OPIO_DEADKEYMAP:	/* set accent key translation table (compat) */
 #ifndef KBD_DISABLE_KEYMAP_LOAD
-		error = accent_change_ok(kbd->kb_accentmap,
-		    (accentmap_t *)arg, curthread);
+		accentmapp = malloc(sizeof(*accentmapp), M_TEMP, M_WAITOK);
+		if (cmd == OPIO_DEADKEYMAP) {
+			oaccentmapp = (oaccentmap_t *)arg;
+			accentmapp->n_accs = oaccentmapp->n_accs;
+			for (i = 0; i < NUM_DEADKEYS; i++) {
+				for (j = 0; j < NUM_ACCENTCHARS; j++) {
+					accentmapp->acc[i].map[j][0] =
+					    oaccentmapp->acc[i].map[j][0];
+					accentmapp->acc[i].map[j][1] =
+					    oaccentmapp->acc[i].map[j][1];
+					accentmapp->acc[i].accchar =
+					    oaccentmapp->acc[i].accchar;
+				}
+			}
+		} else {
+			error = copyin(*(void **)arg, accentmapp, sizeof(*accentmapp));
+			if (error != 0) {
+				free(accentmapp, M_TEMP);
+				return (error);
+			}
+		}
+
+		error = accent_change_ok(kbd->kb_accentmap, accentmapp, curthread);
 		if (error != 0) {
+			free(accentmapp, M_TEMP);
 			return (error);
 		}
-		bcopy(arg, kbd->kb_accentmap, sizeof(*kbd->kb_accentmap));
+		bcopy(accentmapp, kbd->kb_accentmap, sizeof(*kbd->kb_accentmap));
+		free(accentmapp, M_TEMP);
 		break;
 #else
 		return (ENODEV);
diff --git a/sys/dev/kbdmux/kbdmux.c b/sys/dev/kbdmux/kbdmux.c
--- a/sys/dev/kbdmux/kbdmux.c
+++ b/sys/dev/kbdmux/kbdmux.c
@@ -1243,6 +1243,7 @@
 	case OPIO_KEYMAP:	/* set keyboard translation table (compat) */
 	case PIO_KEYMAPENT:	/* set keyboard translation table entry */
 	case PIO_DEADKEYMAP:	/* set accent key translation table */
+	case OPIO_DEADKEYMAP:	/* set accent key translation table (compat) */
 		KBDMUX_LOCK(state);
                 state->ks_accents = 0;
 
diff --git a/sys/dev/syscons/syscons.c b/sys/dev/syscons/syscons.c
--- a/sys/dev/syscons/syscons.c
+++ b/sys/dev/syscons/syscons.c
@@ -1598,6 +1598,8 @@
 	case OPIO_KEYMAP: /* set keyboard translation table (compat) */
 	case GIO_DEADKEYMAP: /* get accent key translation table */
 	case PIO_DEADKEYMAP: /* set accent key translation table */
+	case OGIO_DEADKEYMAP: /* get accent key translation table (compat) */
+	case OPIO_DEADKEYMAP: /* set accent key translation table (compat) */
 	case GETFKEY: /* get function key string */
 	case SETFKEY: /* set function key string */
 		error = kbdd_ioctl(sc->kbd, cmd, data);
diff --git a/sys/dev/usb/input/ukbd.c b/sys/dev/usb/input/ukbd.c
--- a/sys/dev/usb/input/ukbd.c
+++ b/sys/dev/usb/input/ukbd.c
@@ -1862,6 +1862,7 @@
 	case PIO_KEYMAPENT:		/* set keyboard translation table
 					 * entry */
 	case PIO_DEADKEYMAP:		/* set accent key translation table */
+	case OPIO_DEADKEYMAP:		/* set accent key translation table (compat) */
 		sc->sc_accents = 0;
 		/* FALLTHROUGH */
 	default:
diff --git a/sys/dev/vkbd/vkbd.c b/sys/dev/vkbd/vkbd.c
--- a/sys/dev/vkbd/vkbd.c
+++ b/sys/dev/vkbd/vkbd.c
@@ -1207,6 +1207,7 @@
 	case OPIO_KEYMAP:	/* set keyboard translation table (compat) */
 	case PIO_KEYMAPENT:	/* set keyboard translation table entry */
 	case PIO_DEADKEYMAP:	/* set accent key translation table */
+	case OPIO_DEADKEYMAP:	/* set accent key translation table (compat) */
 		state->ks_accents = 0;
 		/* FALLTHROUGH */
 
diff --git a/sys/dev/vt/vt_core.c b/sys/dev/vt/vt_core.c
--- a/sys/dev/vt/vt_core.c
+++ b/sys/dev/vt/vt_core.c
@@ -2403,7 +2403,9 @@
 	case GIO_KEYMAP:
 	case PIO_KEYMAP:
 	case GIO_DEADKEYMAP:
+	case OGIO_DEADKEYMAP:
 	case PIO_DEADKEYMAP:
+	case OPIO_DEADKEYMAP:
 	case GETFKEY:
 	case SETFKEY:
 	case KDGKBINFO:
diff --git a/sys/sys/kbio.h b/sys/sys/kbio.h
--- a/sys/sys/kbio.h
+++ b/sys/sys/kbio.h
@@ -199,8 +199,8 @@
 #define ACC(x)		((x)+F_ACC)
 
 struct acc_t {
-	u_char		accchar;
-	u_char		map[NUM_ACCENTCHARS][2];
+	u_int		accchar;
+	u_int		map[NUM_ACCENTCHARS][2];
 };
 
 struct accentmap {
@@ -209,6 +209,19 @@
 };
 typedef struct accentmap accentmap_t;
 
+#ifdef _KERNEL
+struct oacc_t {
+	u_char		accchar;
+	u_char		map[NUM_ACCENTCHARS][2];
+};
+
+struct oaccentmap {
+	u_short		n_accs;
+	struct oacc_t	acc[NUM_DEADKEYS];
+};
+typedef struct oaccentmap oaccentmap_t;
+#endif /* _KERNEL */
+
 struct keyarg {
 	u_short		keynum;
 	struct keyent_t	key;
@@ -241,8 +254,13 @@
 #define OGIO_KEYMAP 	_IOR('k', 6, okeymap_t)
 #define OPIO_KEYMAP 	_IOW('k', 7, okeymap_t)
 #endif /* _KERNEL */
-#define GIO_DEADKEYMAP 	_IOR('k', 8, accentmap_t)
-#define PIO_DEADKEYMAP 	_IOW('k', 9, accentmap_t)
+/* XXX: Should have accentmap_t as an argument, but that's too big for ioctl()! */
+#define GIO_DEADKEYMAP 	 _IO('k', 8)
+#define PIO_DEADKEYMAP 	 _IO('k', 9)
+#ifdef _KERNEL
+#define OGIO_DEADKEYMAP	_IOR('k', 8, oaccentmap_t)
+#define OPIO_DEADKEYMAP	_IOW('k', 9, oaccentmap_t)
+#endif /* _KERNEL */
 #define GIO_KEYMAPENT 	_IOWR('k', 10, keyarg_t)
 #define PIO_KEYMAPENT 	_IOW('k', 11, keyarg_t)