diff --git a/sys/dev/drm/amd/amdgpu/si_dpm.c b/sys/dev/drm/amd/amdgpu/si_dpm.c
--- a/sys/dev/drm/amd/amdgpu/si_dpm.c
+++ b/sys/dev/drm/amd/amdgpu/si_dpm.c
@@ -3211,6 +3211,10 @@ static u16 btc_find_voltage(struct atom_voltage_table *table, u16 voltage)
 		if (voltage <= table->entries[i].value)
 			return table->entries[i].value;
 
+	/* DF-3587: count == 0 makes count-1 wrap to 0xffffffff -> wild read. */
+	if (table->count == 0)
+		return 0;
+
 	return table->entries[table->count - 1].value;
 }