diff --git a/sys/dev/drm/radeon/rv770_dpm.c b/sys/dev/drm/radeon/rv770_dpm.c
--- a/sys/dev/drm/radeon/rv770_dpm.c
+++ b/sys/dev/drm/radeon/rv770_dpm.c
@@ -1138,6 +1138,8 @@
 	       pi->vddc_table[i].vddc));
 	     i++);
 
+	if (i >= pi->valid_vddc_entries)
+		i = pi->valid_vddc_entries - 1;
 	table->maxVDDCIndexInPPTable =
 		pi->vddc_table[i].vddc_index;