thunderbolt: Check that lane 1 is in CL0 before enabling lane bonding

Marek reported that when BlackMagic UltraStudio device is connected the kernel repeatedly tries to enable lane bonding without success making the device non-functional. It looks like the device does not have lane 1 connected at all so even though it is enabled we should not try to bond the lanes. For this reason check that lane 1 is in fact CL0 (connected, active) before attempting to bond the lanes. Reported-by: Marek Šanta <[email protected]> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217737 Cc: [email protected] Signed-off-by: Mika Westerberg <[email protected]>
RoPieee · Sep 15, 2023 · a9fdf5f · a9fdf5f
1 parent 582620d
commit a9fdf5f
Showing 1 changed file with 7 additions and 0 deletions.
diff --git a/drivers/thunderbolt/switch.c b/drivers/thunderbolt/switch.c
@@ -2725,6 +2725,13 @@ int tb_switch_lane_bonding_enable(struct tb_switch *sw)
 	    !tb_port_is_width_supported(down, TB_LINK_WIDTH_DUAL))
 		return 0;
 
+	/*
+	 * Both lanes need to be in CL0. Here we assume lane 0 already be in
+	 * CL0 and check just for lane 1.
+	 */
+	if (tb_wait_for_port(down->dual_link_port, false) <= 0)
+		return -ENOTCONN;
+
 	ret = tb_port_lane_bonding_enable(up);
 	if (ret) {
 		tb_port_warn(up, "failed to enable lane bonding\n");