[PATCH AUTOSEL 5.4 31/73] net: phy: prefer 1000baseT over 1000baseKX

[Sasha Levin]

From: "Russell King (Oracle)" <rmk+kernel@xxxxxxxxxxxxxxx>

[ Upstream commit f20f94f7f52c4685c81754f489ffcc72186e8bdb ]

The PHY settings table is supposed to be sorted by descending match
priority - in other words, earlier entries are preferred over later
entries.

The order of 1000baseKX/Full and 1000baseT/Full is such that we
prefer 1000baseKX/Full over 1000baseT/Full, but 1000baseKX/Full is
a lot rarer than 1000baseT/Full, and thus is much less likely to
be preferred.

This causes phylink problems - it means a fixed link specifying a
speed of 1G and full duplex gets an ethtool linkmode of 1000baseKX/Full
rather than 1000baseT/Full as would be expected - and since we offer
userspace a software emulation of a conventional copper PHY, we want
to offer copper modes in preference to anything else. However, we do
still want to allow the rarer modes as well.

Hence, let's reorder these two modes to prefer copper.

Tested-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
Signed-off-by: Russell King (Oracle) <rmk+kernel@xxxxxxxxxxxxxxx>
Reviewed-by: Andrew Lunn <andrew@xxxxxxx>
Reported-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
Link: https://lore.kernel.org/r/E1muvFO-00F6jY-1K@xxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/net/phy/phy-core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/phy/phy-core.c b/drivers/net/phy/phy-core.c
index 9412669b579c7..84064120918f0 100644
--- a/drivers/net/phy/phy-core.c
+++ b/drivers/net/phy/phy-core.c
@@ -128,11 +128,11 @@ static const struct phy_setting settings[] = {
 	PHY_SETTING(   2500, FULL,   2500baseT_Full		),
 	PHY_SETTING(   2500, FULL,   2500baseX_Full		),
 	/* 1G */
-	PHY_SETTING(   1000, FULL,   1000baseKX_Full		),
 	PHY_SETTING(   1000, FULL,   1000baseT_Full		),
 	PHY_SETTING(   1000, HALF,   1000baseT_Half		),
 	PHY_SETTING(   1000, FULL,   1000baseT1_Full		),
 	PHY_SETTING(   1000, FULL,   1000baseX_Full		),
+	PHY_SETTING(   1000, FULL,   1000baseKX_Full		),
 	/* 100M */
 	PHY_SETTING(    100, FULL,    100baseT_Full		),
 	PHY_SETTING(    100, FULL,    100baseT1_Full		),
-- 
2.34.1