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From: Russell King - ARM Linux admin <>
To: "René van Dorst" <>
Cc: John Crispin <>,
	Sean Wang <>,
	Nelson Chang <>,
	"David S . Miller" <>,
	Matthias Brugger <>,,,,,
	Frank Wunderlich <>,
	Stefan Roese <>
Subject: Re: [PATCH net-next v3 2/3] net: ethernet: mediatek: Re-add support SGMII
Date: Sat, 24 Aug 2019 10:21:56 +0100
Message-ID: <> (raw)
In-Reply-To: <>

On Fri, Aug 23, 2019 at 03:45:15PM +0200, René van Dorst wrote:
> +	switch (state->interface) {
> +		phylink_set(mask, 10baseT_Half);
> +		phylink_set(mask, 10baseT_Full);
> +		phylink_set(mask, 100baseT_Half);
> +		phylink_set(mask, 100baseT_Full);

You also want 1000baseX_Full here - the connected PHY could have a fiber
interface on it.

> +		/* fall through */
>  		phylink_set(mask, 1000baseT_Full);

I don't know enough about this interface type to comment whether it
should support 1000baseX_Full - if this is connected to a PHY that may
support fiber, then it ought to set it.

> +		break;
> +		phylink_set(mask, 2500baseX_Full);
> +		/* fall through */
> +		phylink_set(mask, 1000baseX_Full);

Both should be set.  The reasoning here is that if you have a
Fiberchannel 4Gbaud SFP plugged in and connected directly to the
MAC, it can operate at either 2500Base-X or 1000Base-X.  If we
decide to operate at 2500Base-X, then PHY_INTERFACE_MODE_2500BASEX
will be chosen.  Otherwise, PHY_INTERFACE_MODE_1000BASEX will be

The user can use ethtool to control which interface mode is used
by adjusting the advertise mask and/or placing the interface in
manual mode and setting the speed directly.  This will change
the PHY_INTERFACE_MODE_xxxxBASEX (via phylink_helper_basex_speed())
between the two settings.

If we lose 2500baseX_Full when 1000Base-X is selected, the user
will not be able to go back to 2500Base-X mode.

Yes, it's a little confusing and has slightly different rules
from the other modes - partly due to phylink_helper_basex_speed().
These are the only interface modes that we dynamically switch
between depending on the settings that the user configures via

RMK's Patch system:
FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up
According to 11.9Mbps down 500kbps up

  reply index

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-23 13:45 [PATCH net-next v3 0/3] net: ethernet: mediatek: convert to PHYLINK René van Dorst
2019-08-23 13:45 ` [PATCH net-next v3 1/3] net: ethernet: mediatek: Add basic PHYLINK support René van Dorst
2019-08-24  9:11   ` Russell King - ARM Linux admin
2019-08-24 12:33     ` René van Dorst
2019-08-23 13:45 ` [PATCH net-next v3 2/3] net: ethernet: mediatek: Re-add support SGMII René van Dorst
2019-08-24  9:21   ` Russell King - ARM Linux admin [this message]
2019-08-24 13:11     ` René van Dorst
2019-08-24 13:32       ` Russell King - ARM Linux admin
2019-08-25 11:41         ` René van Dorst
2019-08-23 13:45 ` [PATCH net-next v3 3/3] dt-bindings: net: ethernet: Update mt7622 docs and dts to reflect the new phylink API René van Dorst
2019-08-23 17:56 ` Aw: [PATCH net-next v3 0/3] net: ethernet: mediatek: convert to PHYLINK Frank Wunderlich
2019-08-24  7:41   ` René van Dorst

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