diff --git a/drivers/gpu/drm/radeon/r600_dpm.c b/drivers/gpu/drm/radeon/r600_dpm.c
index 34ea5d6ee4be..89c46c55f93d 100644
--- a/drivers/gpu/drm/radeon/r600_dpm.c
+++ b/drivers/gpu/drm/radeon/r600_dpm.c
@@ -1246,3 +1246,13 @@ u16 r600_get_pcie_lane_support(struct radeon_device *rdev,
 		return 16;
 	}
 }
+
+u8 r600_encode_pci_lane_width(u32 lanes)
+{
+	u8 encoded_lanes[] = { 0, 1, 2, 0, 3, 0, 0, 0, 4, 0, 0, 0, 5, 0, 0, 0, 6 };
+
+	if (lanes > 16)
+		return 0;
+
+	return encoded_lanes[lanes];
+}
diff --git a/drivers/gpu/drm/radeon/r600_dpm.h b/drivers/gpu/drm/radeon/r600_dpm.h
index 71d5d93c371b..8dc1fbd9dbf1 100644
--- a/drivers/gpu/drm/radeon/r600_dpm.h
+++ b/drivers/gpu/drm/radeon/r600_dpm.h
@@ -227,5 +227,6 @@ enum radeon_pcie_gen r600_get_pcie_gen_support(struct radeon_device *rdev,
 u16 r600_get_pcie_lane_support(struct radeon_device *rdev,
 			       u16 asic_lanes,
 			       u16 default_lanes);
+u8 r600_encode_pci_lane_width(u32 lanes);
 
 #endif