diff --git a/sys/dev/drm/radeon/btc_dpm.c b/sys/dev/drm/radeon/btc_dpm.c
--- a/sys/dev/drm/radeon/btc_dpm.c
+++ b/sys/dev/drm/radeon/btc_dpm.c
@@ -1989,7 +1989,7 @@
 {
 	u8 i, j;
 
-	if (table->last > SMC_EVERGREEN_MC_REGISTER_ARRAY_SIZE)
+	if (table->last >= SMC_EVERGREEN_MC_REGISTER_ARRAY_SIZE)
 		return -EINVAL;
 
 	if (table->num_entries > MAX_AC_TIMING_ENTRIES)