[PATCH AUTOSEL 6.18-6.12] thunderbolt: Don't disable lane adapter if XDomain lane bonding isn't possible

[Sasha Levin]

From: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>

[ Upstream commit 7c7345bcde6c611fa8fa13e624207c6005798aa8 ]

This happens when firmware connection manager is being used. It will
deal with disabling the lane 1 adapter after the tunnel has been
established and re-enabling it afterwards. For this reason only do this
when we know that lane bonding is possible (e.g running software
connection manager).

Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---

LLM Generated explanations, may be completely bogus:

The background `git log --all` search was killed — it was hanging on
this repo, as expected.

A follow-up `git log -S 'tb_xdomain_link_exit'` (without `--all`)
finished after ~48s, but the hits (`19eef1d98eeda`, `ac3fd01e4c1ef`) are
base-import commits, not a clean “introduced in commit X” answer. That’s
normal on this 6.18.y tree where history is squashed.

The backport analysis doesn’t depend on that: the buggy
`tb_xdomain_link_exit()` path is present in 6.18.43, and the verdict
remains **YES**.

 drivers/thunderbolt/xdomain.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/thunderbolt/xdomain.c b/drivers/thunderbolt/xdomain.c
index 6b16fc7254b8e..b27ef872edeac 100644
--- a/drivers/thunderbolt/xdomain.c
+++ b/drivers/thunderbolt/xdomain.c
@@ -1951,7 +1951,13 @@ static void tb_xdomain_link_exit(struct tb_xdomain *xd)
 	if (tb_port_get_link_generation(down) >= 4) {
 		down->bonded = false;
 		down->dual_link_port->bonded = false;
-	} else if (xd->link_width > TB_LINK_WIDTH_SINGLE) {
+		return;
+	}
+
+	if (!xd->bonding_possible)
+		return;
+
+	if (xd->link_width > TB_LINK_WIDTH_SINGLE) {
 		/*
 		 * Just return port structures back to way they were and
 		 * update credits. No need to update userspace because
-- 
2.53.0