diff mbox series

thunderbolt: Do not create DisplayPort tunnels on adapters of the same router

Message ID 20240327083032.1611284-1-mika.westerberg@linux.intel.com (mailing list archive)
State Accepted
Commit c032cdd48b29549e8283c2fea99e7d91ddefebf7
Headers show
Series thunderbolt: Do not create DisplayPort tunnels on adapters of the same router | expand

Commit Message

Mika Westerberg March 27, 2024, 8:30 a.m. UTC
Probably due to a firmware bug Dell TB16 dock announces that one of its
DisplayPort adapters is actually DP IN. Now this is possible and used
with some external GPUs but not likely in this case as we are dealing
with a dock. Anyways the problem is that the driver tries to create a
DisplayPort tunnel between adapters of the same router which then shows
to user that there is no picture on the display (because there are no
available DP OUT adapters on the dock anymore).

Fix this by not creating DisplayPort tunnels between adapters that are
on the same router.

Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/10265
Fixes: 274baf695b08 ("thunderbolt: Add DP IN added last in the head of the list of DP resources")
Cc: Gil Fine <gil.fine@linux.intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
---
 drivers/thunderbolt/tb.c | 6 ++++++
 1 file changed, 6 insertions(+)

Comments

Mika Westerberg April 2, 2024, 5:51 a.m. UTC | #1
On Wed, Mar 27, 2024 at 10:30:32AM +0200, Mika Westerberg wrote:
> Probably due to a firmware bug Dell TB16 dock announces that one of its
> DisplayPort adapters is actually DP IN. Now this is possible and used
> with some external GPUs but not likely in this case as we are dealing
> with a dock. Anyways the problem is that the driver tries to create a
> DisplayPort tunnel between adapters of the same router which then shows
> to user that there is no picture on the display (because there are no
> available DP OUT adapters on the dock anymore).
> 
> Fix this by not creating DisplayPort tunnels between adapters that are
> on the same router.
> 
> Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/10265
> Fixes: 274baf695b08 ("thunderbolt: Add DP IN added last in the head of the list of DP resources")
> Cc: Gil Fine <gil.fine@linux.intel.com>
> Cc: stable@vger.kernel.org
> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

Applied to fixes.
diff mbox series

Patch

diff --git a/drivers/thunderbolt/tb.c b/drivers/thunderbolt/tb.c
index c5ce7a694b27..360cb95f39aa 100644
--- a/drivers/thunderbolt/tb.c
+++ b/drivers/thunderbolt/tb.c
@@ -1801,6 +1801,12 @@  static struct tb_port *tb_find_dp_out(struct tb *tb, struct tb_port *in)
 			continue;
 		}
 
+		/* Needs to be on different routers */
+		if (in->sw == port->sw) {
+			tb_port_dbg(port, "skipping DP OUT on same router\n");
+			continue;
+		}
+
 		tb_port_dbg(port, "DP OUT available\n");
 
 		/*