net: phy: prefer 1000baseT over 1000baseKX

[ Upstream commit f20f94f ]

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 <[email protected]>
Signed-off-by: Russell King (Oracle) <[email protected]>
Reviewed-by: Andrew Lunn <[email protected]>
Reported-by: Florian Fainelli <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>

Author: Russell King (Oracle)

drivers/net/phy/phy-core.c

@@ -161,11 +161,11 @@ 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		),