[PATCH 6.11 155/184] thunderbolt: Add only on-board retimers when !CONFIG_USB4_DEBUGFS_MARGINING

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

6.11-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Mika Westerberg <mika.westerberg@linux.intel.com>

commit bf791751162ac875a9439426d13f8d4d18151549 upstream.

Normally there is no need to enumerate retimers on the other side of the
cable. This is only needed in special cases where user wants to run
receiver lane margining against the downstream facing port of a retimer.
Furthermore this might confuse the userspace tools such as fwupd because
it cannot read the information it expects from these retimers.

Fix this by changing the retimer enumeration code to add only on-board
retimers when CONFIG_USB4_DEBUGFS_MARGINING is not enabled.

Reported-by: AceLan Kao <acelan.kao@canonical.com>
Tested-by: AceLan Kao <acelan.kao@canonical.com>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=219420
Cc: stable@vger.kernel.org
Fixes: ff6ab055e070 ("thunderbolt: Add receiver lane margining support for retimers")
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/thunderbolt/retimer.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/thunderbolt/retimer.c
+++ b/drivers/thunderbolt/retimer.c
@@ -532,6 +532,8 @@ int tb_retimer_scan(struct tb_port *port
 	}
 
 	ret = 0;
+	if (!IS_ENABLED(CONFIG_USB4_DEBUGFS_MARGINING))
+		max = min(last_idx, max);
 
 	/* Add retimers if they do not exist already */
 	for (i = 1; i <= max; i++) {