6.8-stable review patch. If anyone has any objections, please let me know.
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From: Mika Westerberg mika.westerberg@linux.intel.com
commit c032cdd48b29549e8283c2fea99e7d91ddefebf7 upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/thunderbolt/tb.c | 6 ++++++ 1 file changed, 6 insertions(+)
--- a/drivers/thunderbolt/tb.c +++ b/drivers/thunderbolt/tb.c @@ -1717,6 +1717,12 @@ static struct tb_port *tb_find_dp_out(st 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");
/*