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 <teslan223@xxxxxxxxx> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217737 Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> --- drivers/thunderbolt/switch.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/thunderbolt/switch.c b/drivers/thunderbolt/switch.c index 43171cc1cc2d..bd5815f8f23b 100644 --- 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"); -- 2.40.1
