[PATCH net 1/3] net: dsa: mv88e6xxx: Fix forcing speed & duplex when changing to 2500base-x mode

["Marek Behún" <kabel@kernel.org>]

Commit 64d47d50be7a ("net: dsa: mv88e6xxx: configure interface settings
in mac_config") removed forcing of speed and duplex from
mv88e6xxx_mac_config(), where the link is forced down, and left it only
in mv88e6xxx_mac_link_up(), by which time link is unforced.

It seems that in 2500base-x (at least on 88E6190), if the link is not
forced down, the forcing of new settings for speed and duplex doesn't
take.

Fix this by forcing link down.

Fixes: 64d47d50be7a ("net: dsa: mv88e6xxx: configure interface settings in mac_config")
Signed-off-by: Marek Behún <kabel@kernel.org>
---
 drivers/net/dsa/mv88e6xxx/chip.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index f00cbf5753b9..ddb13cecb3ac 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c
@@ -785,12 +785,17 @@ static void mv88e6xxx_mac_link_up(struct dsa_switch *ds, int port,
 	if ((!mv88e6xxx_phy_is_internal(ds, port) &&
 	     !mv88e6xxx_port_ppu_updates(chip, port)) ||
 	    mode == MLO_AN_FIXED) {
-		/* FIXME: for an automedia port, should we force the link
-		 * down here - what if the link comes up due to "other" media
-		 * while we're bringing the port up, how is the exclusivity
-		 * handled in the Marvell hardware? E.g. port 2 on 88E6390
-		 * shared between internal PHY and Serdes.
+		/* FIXME: we need to force the link down here, otherwise the
+		 * forcing of link speed and duplex by .port_set_speed_duplex()
+		 * doesn't work for some modes.
+		 * But what if the link comes up due to "other" media while
+		 * we're bringing the port up, how is the exclusivity handled in
+		 * the Marvell hardware? E.g. port 2 on 88E6390 shared between
+		 * internal PHY and Serdes.
 		 */
+		if (ops->port_sync_link)
+			err = ops->port_sync_link(chip, port, mode, false);
+
 		err = mv88e6xxx_serdes_pcs_link_up(chip, port, mode, speed,
 						   duplex);
 		if (err)
-- 
2.32.0