Subject: Re: [RFC PATCH net-next 0/3] Make the PHY library stop being so greedy when binding the generic PHY driver

From: "Russell King (Oracle)" <[email-masked]>
Date: Thu, 2 Sep 2021 17:31:44 +0100

On Thu, Sep 02, 2021 at 06:23:42PM +0300, Vladimir Oltean wrote:
> On Thu, Sep 02, 2021 at 02:26:35PM +0100, Russell King (Oracle) wrote:
> > Debian has had support for configuring bridges at boot time via
> > the interfaces file for years. Breaking that is going to upset a
> > lot of people (me included) resulting in busted networks. It
> > would be a sure way to make oneself unpopular.
> >
> > > I expect there to be 2 call paths of phy_attach_direct:
> > > - At probe time. Both the MAC driver and the PHY driver are probing.
> > >   This is what has this patch addresses. There is no issue to return
> > >   -EPROBE_DEFER at that time, since drivers connect to the PHY before
> > >   they register their netdev. So if connecting defers, there is no
> > >   netdev to unregister, and user space knows nothing of this.
> > > - At .ndo_open time. This is where it maybe gets interesting, but not to
> > >   user space. If you open a netdev and it connects to the PHY then, I
> > >   wouldn't expect the PHY to be undergoing a probing process, all of
> > >   that should have been settled by then, should it not? Where it might
> > >   get interesting is with NFS root, and I admit I haven't tested that.
> >
> > I don't think you can make that assumption. Consider the case where
> > systemd is being used, DSA stuff is modular, and we're trying to
> > setup a bridge device on DSA. DSA could be probing while the bridge
> > is being setup.
> >
> > Sadly, this isn't theoretical. I've ended up needing:
> >
> > 	pre-up sleep 1
> >
> > in my bridge configuration to allow time for DSA to finish probing.
> > It's not a pleasant solution, nor a particularly reliable one at
> > that, but it currently works around the problem.
> 
> What problem? This is the first time I've heard of this report, and you
> should definitely not need that.

I found it when upgrading the Clearfog by the DSL modems to v5.13.
When I rebooted it with a previously working kernel (v5.7) it has
never had a problem. With v5.13, it failed to add all the lan ports
into the bridge, because the bridge was still being setup by the
kernel while userspace was trying to configure it. Note that I have
extra debug in my kernels, hence the extra messages:

Aug 30 11:29:52 sw-dsl kernel: [    3.308583] Marvell 88E1540 mv88e6xxx-0:03: probe: irq=78
Aug 30 11:29:52 sw-dsl kernel: [    3.308595] Marvell 88E1540 mv88e6xxx-0:03: probe: irq=78
Aug 30 11:29:52 sw-dsl kernel: [    3.332403] Marvell 88E1540 mv88e6xxx-0:04: probe: irq=79
Aug 30 11:29:52 sw-dsl kernel: [    3.332415] Marvell 88E1540 mv88e6xxx-0:04: probe: irq=79
Aug 30 11:29:52 sw-dsl kernel: [    3.412638] Marvell 88E1545 mv88e6xxx-0:0f: probe: irq=-1
Aug 30 11:29:52 sw-dsl kernel: [    3.412649] Marvell 88E1545 mv88e6xxx-0:0f: probe: irq=-1
Aug 30 11:29:52 sw-dsl kernel: [    3.515888] libphy: mv88e6xxx SMI: probed

Here, userspace starts configuring eno1, the ethernet port connected
to the DSA switch:

Aug 30 11:29:52 sw-dsl kernel: [    3.536090] mvneta f1030000.ethernet eno1: configuring for inband/1000base-x link mode
Aug 30 11:29:52 sw-dsl kernel: [    3.536109] mvneta f1030000.ethernet eno1: major config 1000base-x
Aug 30 11:29:52 sw-dsl kernel: [    3.536117] mvneta f1030000.ethernet eno1: phylink_mac_config: mode=inband/1000base-x/Unknown/Unknown adv=0000000,00000200,00002240 pause=04 link=0 an=1
Aug 30 11:29:52 sw-dsl kernel: [    3.536135] mvneta f1030000.ethernet eno1: mac link down
Aug 30 11:29:52 sw-dsl kernel: [    3.536135] mvneta f1030000.ethernet eno1: mac link down
Aug 30 11:29:52 sw-dsl kernel: [    3.536146] mvneta f1030000.ethernet eno1: mac link down
Aug 30 11:29:52 sw-dsl kernel: [    3.536146] mvneta f1030000.ethernet eno1: mac link down
Aug 30 11:29:52 sw-dsl kernel: [    3.572013] mvneta f1030000.ethernet eno1: mac link up
Aug 30 11:29:52 sw-dsl kernel: [    3.572016] mvneta f1030000.ethernet eno1: mac link up
Aug 30 11:29:52 sw-dsl kernel: [    3.572046] mvneta f1030000.ethernet eno1: Link is Up - 1Gbps/Full - flow control rx/tx
Aug 30 11:29:52 sw-dsl kernel: [    3.657820] 8021q: 802.1Q VLAN Support v1.8

We get the link to eno1 going down/up due to DSA's actions:

Aug 30 11:29:53 sw-dsl kernel: [    4.291882] mvneta f1030000.ethernet eno1: Link is Down
Aug 30 11:29:53 sw-dsl kernel: [    4.309425] mvneta f1030000.ethernet eno1: mac link down
Aug 30 11:29:53 sw-dsl kernel: [    4.309425] mvneta f1030000.ethernet eno1: mac link down
Aug 30 11:29:53 sw-dsl kernel: [    4.309440] mvneta f1030000.ethernet eno1: configuring for inband/1000base-x link mode
Aug 30 11:29:53 sw-dsl kernel: [    4.309447] mvneta f1030000.ethernet eno1: major config 1000base-x
Aug 30 11:29:53 sw-dsl kernel: [    4.309454] mvneta f1030000.ethernet eno1: phylink_mac_config: mode=inband/1000base-x/Unknown/Unknown adv=0000000,00000200,00002240 pause=04 link=0 an=1
Aug 30 11:29:53 sw-dsl kernel: [    4.345013] mvneta f1030000.ethernet eno1: mac link up
Aug 30 11:29:53 sw-dsl kernel: [    4.345014] mvneta f1030000.ethernet eno1: mac link up
Aug 30 11:29:53 sw-dsl kernel: [    4.345036] mvneta f1030000.ethernet eno1: Link is Up - 1Gbps/Full - flow control rx/tx

DSA then starts initialising the ports:

Aug 30 11:29:53 sw-dsl kernel: [    4.397647] mv88e6085 f1072004.mdio-mii:04 lan5 (uninitialized): PHY [mv88e6xxx-0:00] driver [Marvell 88E1540] (irq=75)
Aug 30 11:29:53 sw-dsl kernel: [    4.397663] mv88e6085 f1072004.mdio-mii:04 lan5 (uninitialized): phy: setting supported 0000000,00000000,000022ef advertising
0000000,00000000,000022ef
Aug 30 11:29:53 sw-dsl kernel: [    4.493080] mv88e6085 f1072004.mdio-mii:04 lan4 (uninitialized): PHY [mv88e6xxx-0:01] driver [Marvell 88E1540] (irq=76)
Aug 30 11:29:53 sw-dsl kernel: [    4.493093] mv88e6085 f1072004.mdio-mii:04 lan4 (uninitialized): phy: setting supported 0000000,00000000,000022ef advertising
0000000,00000000,000022ef
Aug 30 11:29:53 sw-dsl kernel: [    4.577070] mv88e6085 f1072004.mdio-mii:04 lan3 (uninitialized): PHY [mv88e6xxx-0:02] driver [Marvell 88E1540] (irq=77)
Aug 30 11:29:53 sw-dsl kernel: [    4.577081] mv88e6085 f1072004.mdio-mii:04 lan3 (uninitialized): phy: setting supported 0000000,00000000,000022ef advertising
0000000,00000000,000022ef

Meanwhile userspace is trying to setup the bridge while this is going
on, and has tried to add the non-existent lan2 at this point, but
lan4 has just been created in time, so Debian's bridge support adds
it to the brdsl bridge:

Aug 30 11:29:53 sw-dsl kernel: [    4.652237] brdsl: port 1(lan4) entered blocking state
Aug 30 11:29:53 sw-dsl kernel: [    4.652250] brdsl: port 1(lan4) entered disabled state

DSA continues setting up the other ports, here lan2, but the bridge
setup scripts have already moved on past lan2.

Aug 30 11:29:53 sw-dsl kernel: [    4.674038] mv88e6085 f1072004.mdio-mii:04 lan2 (uninitialized): PHY [mv88e6xxx-0:03] driver [Marvell 88E1540] (irq=78)
Aug 30 11:29:53 sw-dsl kernel: [    4.674052] mv88e6085 f1072004.mdio-mii:04 lan2 (uninitialized): phy: setting supported 0000000,00000000,000022ef advertising
0000000,00000000,000022ef
Aug 30 11:29:53 sw-dsl kernel: [    4.674612] device lan4 entered promiscuous mode
Aug 30 11:29:53 sw-dsl kernel: [    4.785886] device eno1 entered promiscuous mode
Aug 30 11:29:53 sw-dsl kernel: [    4.786971] mv88e6085 f1072004.mdio-mii:04 lan4: configuring for phy/gmii link mode
Aug 30 11:29:53 sw-dsl kernel: [    4.786980] mv88e6085 f1072004.mdio-mii:04 lan4: major config gmii
Aug 30 11:29:53 sw-dsl kernel: [    4.786986] mv88e6085 f1072004.mdio-mii:04 lan4: phylink_mac_config: mode=phy/gmii/Unknown/Unknown adv=0000000,00000000,00000000 pause=00 link=0 an=0
Aug 30 11:29:53 sw-dsl kernel: [    4.786996] mv88e6085 f1072004.mdio-mii:04: p1: dsa_port_phylink_mac_config()
Aug 30 11:29:53 sw-dsl kernel: [    4.789977] 8021q: adding VLAN 0 to HW filter
on device lan4
Aug 30 11:29:53 sw-dsl kernel: [    4.836720] brdsl: port 2(eno2) entered blocking state
Aug 30 11:29:53 sw-dsl kernel: [    4.836733] brdsl: port 2(eno2) entered disabled state

Here, the SFP port (on eno2) is added to the bridge.

Aug 30 11:29:53 sw-dsl kernel: [    4.836907] device eno2 entered promiscuous mode
Aug 30 11:29:53 sw-dsl kernel: [    4.837011] brdsl: port 2(eno2) entered blocking state
Aug 30 11:29:53 sw-dsl kernel: [    4.837019] brdsl: port 2(eno2) entered forwarding state
Aug 30 11:29:53 sw-dsl kernel: [    4.837058] IPv6: ADDRCONF(NETDEV_CHANGE): brdsl: link becomes ready
Aug 30 11:29:53 sw-dsl kernel: [    4.846989] mv88e6085 f1072004.mdio-mii:04 lan4: phy link down gmii/Unknown/Unknown/off
Aug 30 11:29:53 sw-dsl kernel: [    4.896264] mv88e6085 f1072004.mdio-mii:04 lan1 (uninitialized): PHY [mv88e6xxx-0:04] driver [Marvell 88E1540] (irq=79)
Aug 30 11:29:53 sw-dsl kernel: [    4.896278] mv88e6085 f1072004.mdio-mii:04 lan1 (uninitialized): phy: setting supported 0000000,00000000,000022ef advertising
0000000,00000000,000022ef
Aug 30 11:29:53 sw-dsl kernel: [    4.934514] DSA: tree 0 setup

Here, the DSA tree has finally finished initialising in the kernel.

Aug 30 11:29:53 sw-dsl kernel: [    4.986877] mv88e6085 f1072004.mdio-mii:04 lan1: configuring for phy/gmii link mode
Aug 30 11:29:53 sw-dsl kernel: [    4.986890] mv88e6085 f1072004.mdio-mii:04 lan1: major config gmii
Aug 30 11:29:53 sw-dsl kernel: [    4.986896] mv88e6085 f1072004.mdio-mii:04 lan1: phylink_mac_config: mode=phy/gmii/Unknown/Unknown adv=0000000,00000000,00000000 pause=00 link=0 an=0
Aug 30 11:29:53 sw-dsl kernel: [    4.986907] mv88e6085 f1072004.mdio-mii:04: p4: dsa_port_phylink_mac_config()
Aug 30 11:29:53 sw-dsl kernel: [    4.990199] 8021q: adding VLAN 0 to HW filter
on device lan1
Aug 30 11:29:54 sw-dsl kernel: [    5.041313] mv88e6085 f1072004.mdio-mii:04 lan1: phy link down gmii/Unknown/Unknown/off
Aug 30 11:29:56 sw-dsl kernel: [    7.630016] mv88e6085 f1072004.mdio-mii:04 lan4: phy link up gmii/1Gbps/Full/off
Aug 30 11:29:56 sw-dsl kernel: [    7.630031] mv88e6085 f1072004.mdio-mii:04 lan4: phylink_mac_config: mode=phy/gmii/1Gbps/Full adv=0000000,00000000,00000000 pause=00 link=1 an=0
Aug 30 11:29:56 sw-dsl kernel: [    7.630043] mv88e6085 f1072004.mdio-mii:04: p1: dsa_port_phylink_mac_config()
Aug 30 11:29:56 sw-dsl kernel: [    7.630294] mv88e6085 f1072004.mdio-mii:04 lan4: Link is Up - 1Gbps/Full - flow control off
Aug 30 11:29:56 sw-dsl kernel: [    7.630312] brdsl: port 1(lan4) entered blocking state
Aug 30 11:29:56 sw-dsl kernel: [    7.630321] brdsl: port 1(lan4) entered forwarding state

I then notice that my Internet connection hasn't come back, so I start
poking about with it, first adding it to the bridge:

Aug 30 11:31:13 sw-dsl kernel: [   84.990122] brdsl: port 3(lan2) entered blocking state
Aug 30 11:31:13 sw-dsl kernel: [   84.990134] brdsl: port 3(lan2) entered disabled state
Aug 30 11:31:14 sw-dsl kernel: [   85.063971] device lan2 entered promiscuous mode

And then setting it to up state and configuring its vlan settings:

Aug 30 11:32:45 sw-dsl kernel: [  176.476090] mv88e6085 f1072004.mdio-mii:04 lan2: configuring for phy/gmii link mode
Aug 30 11:32:45 sw-dsl kernel: [  176.476103] mv88e6085 f1072004.mdio-mii:04 lan2: major config gmii
Aug 30 11:32:45 sw-dsl kernel: [  176.476109] mv88e6085 f1072004.mdio-mii:04 lan2: phylink_mac_config: mode=phy/gmii/Unknown/Unknown adv=0000000,00000000,00000000 pause=00 link=0 an=0
Aug 30 11:32:45 sw-dsl kernel: [  176.476120] mv88e6085 f1072004.mdio-mii:04: p3: dsa_port_phylink_mac_config()
Aug 30 11:32:45 sw-dsl kernel: [  176.479495] 8021q: adding VLAN 0 to HW filter
on device lan2
Aug 30 11:32:45 sw-dsl kernel: [  176.537796] mv88e6085 f1072004.mdio-mii:04 lan2: phy link down gmii/Unknown/Unknown/off
Aug 30 11:32:48 sw-dsl kernel: [  179.280863] mv88e6085 f1072004.mdio-mii:04 lan2: phy link up gmii/1Gbps/Full/rx/tx
Aug 30 11:32:48 sw-dsl kernel: [  179.280877] mv88e6085 f1072004.mdio-mii:04 lan2: phylink_mac_config: mode=phy/gmii/1Gbps/Full adv=0000000,00000000,00000000 pause=03 link=1 an=0
Aug 30 11:32:48 sw-dsl kernel: [  179.280888] mv88e6085 f1072004.mdio-mii:04: p3: dsa_port_phylink_mac_config()
Aug 30 11:32:48 sw-dsl kernel: [  179.280894] mv88e6085 f1072004.mdio-mii:04: p3: dsa_port_phylink_mac_link_up()
Aug 30 11:32:48 sw-dsl kernel: [  179.282958] mv88e6085 f1072004.mdio-mii:04 lan2: Link is Up - 1Gbps/Full - flow control rx/tx

I had:

iface brdsl inet manual
        bridge-ports lan2 lan4
        bridge-maxwait 0
	up brctl addif $IFACE eno2

I now have:
iface brdsl inet manual
        bridge-ports lan2 lan4
        bridge-waitport 10
        bridge-maxwait 0
        pre-up sleep 1
	up brctl addif $IFACE eno2

to ensure that all ports get properly configured.

What can be seen from the above is that there is most definitely a race.
It is possible to start configuring a DSA switch before the DSA switch
driver has finished being probed by the kernel.

Here is the kernel log from v5.7 which has never showed these problems,
because DSA seemed to always setup everything in kernel space prior to
userspace beginning configuration:

Aug 25 23:03:54 sw-dsl kernel: [    5.793137] mvneta f1030000.ethernet eno1: configuring for inband/1000base-x link mode
Aug 25 23:03:54 sw-dsl kernel: [    5.793148] mvneta f1030000.ethernet eno1: config interface 1000base-x
Aug 25 23:03:54 sw-dsl kernel: [    5.793157] mvneta f1030000.ethernet eno1: phylink_mac_config: mode=inband/1000base-x/Unknown/Unknown adv=000,00000200,00002240 pause=04 link=0 an=1
Aug 25 23:03:54 sw-dsl kernel: [    5.793168] mvneta f1030000.ethernet eno1: mac link down
Aug 25 23:03:54 sw-dsl kernel: [    5.793170] mvneta f1030000.ethernet eno1: mac link down
Aug 25 23:03:54 sw-dsl kernel: [    5.819769] mvneta f1030000.ethernet eno1: mac link up
Aug 25 23:03:54 sw-dsl kernel: [    5.819792] mvneta f1030000.ethernet eno1: Link is Up - 1Gbps/Full - flow control rx/tx
Aug 25 23:03:54 sw-dsl kernel: [    5.948900] 8021q: 802.1Q VLAN Support v1.8
  6.459779] mv88e6085 f1072004.mdio-mii:04: nonfatal error -95 setting MTU on port 0
Aug 25 23:03:54 sw-dsl kernel: [    6.462890] mv88e6085 f1072004.mdio-mii:04 lan5 (uninitialized): PHY [mv88e6xxx-0:00] driver [Marvell 88E1540] (irq=67)
Aug 25 23:03:54 sw-dsl kernel: [    6.462905] mv88e6085 f1072004.mdio-mii:04 lan5 (uninitialized): phy: setting supported 000,00000000,000022ef advertising 000,00000000,000022ef
Aug 25 23:03:54 sw-dsl kernel: [    6.465904] mv88e6085 f1072004.mdio-mii:04: nonfatal error -95 setting MTU on port 1
Aug 25 23:03:54 sw-dsl kernel: [    6.468101] mv88e6085 f1072004.mdio-mii:04 lan4 (uninitialized): PHY [mv88e6xxx-0:01] driver [Marvell 88E1540] (irq=68)
Aug 25 23:03:54 sw-dsl kernel: [    6.468109] mv88e6085 f1072004.mdio-mii:04 lan4 (uninitialized): phy: setting supported 000,00000000,000022ef advertising 000,00000000,000022ef
Aug 25 23:03:54 sw-dsl kernel: [    6.472162] mv88e6085 f1072004.mdio-mii:04: nonfatal error -95 setting MTU on port 2
Aug 25 23:03:54 sw-dsl kernel: [    6.474247] mv88e6085 f1072004.mdio-mii:04 lan3 (uninitialized): PHY [mv88e6xxx-0:02] driver [Marvell 88E1540] (irq=69)
Aug 25 23:03:54 sw-dsl kernel: [    6.474261] mv88e6085 f1072004.mdio-mii:04 lan3 (uninitialized): phy: setting supported 000,00000000,000022ef advertising 000,00000000,000022ef
Aug 25 23:03:54 sw-dsl kernel: [    6.481824] mv88e6085 f1072004.mdio-mii:04: nonfatal error -95 setting MTU on port 3
Aug 25 23:03:54 sw-dsl kernel: [    6.486354] mv88e6085 f1072004.mdio-mii:04 lan2 (uninitialized): PHY [mv88e6xxx-0:03] driver [Marvell 88E1540] (irq=70)
Aug 25 23:03:54 sw-dsl kernel: [    6.486363] mv88e6085 f1072004.mdio-mii:04 lan2 (uninitialized): phy: setting supported 000,00000000,000022ef advertising 000,00000000,000022ef
Aug 25 23:03:54 sw-dsl kernel: [    6.498494] mv88e6085 f1072004.mdio-mii:04: nonfatal error -95 setting MTU on port 4
Aug 25 23:03:54 sw-dsl kernel: [    6.502272] mv88e6085 f1072004.mdio-mii:04 lan1 (uninitialized): PHY [mv88e6xxx-0:04] driver [Marvell 88E1540] (irq=71)
Aug 25 23:03:54 sw-dsl kernel: [    6.502279] mv88e6085 f1072004.mdio-mii:04 lan1 (uninitialized): phy: setting supported 000,00000000,000022ef advertising 000,00000000,000022ef
Aug 25 23:03:54 sw-dsl kernel: [    6.532258] mv88e6085 f1072004.mdio-mii:04: nonfatal error -95 setting MTU on port 6
Aug 25 23:03:54 sw-dsl kernel: [    6.535877] mvneta f1030000.ethernet eno1: Link is Down
Aug 25 23:03:54 sw-dsl kernel: [    6.541733] mvneta f1030000.ethernet eno1: configuring for inband/1000base-x link mode
Aug 25 23:03:54 sw-dsl kernel: [    6.541741] mvneta f1030000.ethernet eno1: config interface 1000base-x
Aug 25 23:03:54 sw-dsl kernel: [    6.541754] mvneta f1030000.ethernet eno1: phylink_mac_config: mode=inband/1000base-x/Unknown/Unknown adv=000,00000200,00002240 pause=04 link=0 an=1
Aug 25 23:03:54 sw-dsl kernel: [    6.541771] mvneta f1030000.ethernet eno1: mac link down
Aug 25 23:03:54 sw-dsl kernel: [    6.541779] mvneta f1030000.ethernet eno1: mac link down
Aug 25 23:03:54 sw-dsl kernel: [    6.541907] DSA: tree 0 setup

Here, the kernel DSA switch driver has finished doing its setup
before we even get to configuring the bridge device below.

Aug 25 23:03:54 sw-dsl kernel: [    6.569105] mvneta f1030000.ethernet eno1: mac link up
Aug 25 23:03:54 sw-dsl kernel: [    6.569113] mvneta f1030000.ethernet eno1: mac link up
Aug 25 23:03:54 sw-dsl kernel: [    6.569139] mvneta f1030000.ethernet eno1: Link is Up - 1Gbps/Full - flow control rx/tx
Aug 25 23:03:55 sw-dsl kernel: [    6.931763] brdsl: port 1(lan2) entered blocking state
Aug 25 23:03:55 sw-dsl kernel: [    6.931769] brdsl: port 1(lan2) entered disabled state
Aug 25 23:03:55 sw-dsl kernel: [    6.932863] device lan2 entered promiscuous mode
Aug 25 23:03:55 sw-dsl kernel: [    7.032838] device eno1 entered promiscuous mode
Aug 25 23:03:55 sw-dsl kernel: [    7.032902] mv88e6085 f1072004.mdio-mii:04 lan2: configuring for phy/gmii link mode
Aug 25 23:03:55 sw-dsl kernel: [    7.032907] mv88e6085 f1072004.mdio-mii:04 lan2: config interface gmii
Aug 25 23:03:55 sw-dsl kernel: [    7.032916] mv88e6085 f1072004.mdio-mii:04 lan2: phylink_mac_config: mode=phy/gmii/Unknown/Unknown adv=000,00000000,00000000 pause=00 link=0 an=0
Aug 25 23:03:55 sw-dsl kernel: [    7.032920] mv88e6085 f1072004.mdio-mii:04: p3: dsa_port_phylink_mac_config()
Aug 25 23:03:55 sw-dsl kernel: [    7.037225] 8021q: adding VLAN 0 to HW filter
on device lan2
Aug 25 23:03:55 sw-dsl kernel: [    7.044979] brdsl: port 2(lan4) entered blocking state
Aug 25 23:03:55 sw-dsl kernel: [    7.044985] brdsl: port 2(lan4) entered disabled state
Aug 25 23:03:55 sw-dsl kernel: [    7.056189] device lan4 entered promiscuous mode
Aug 25 23:03:55 sw-dsl kernel: [    7.107067] mv88e6085 f1072004.mdio-mii:04 lan4: configuring for phy/gmii link mode
Aug 25 23:03:55 sw-dsl kernel: [    7.107073] mv88e6085 f1072004.mdio-mii:04 lan4: config interface gmii
Aug 25 23:03:55 sw-dsl kernel: [    7.107080] mv88e6085 f1072004.mdio-mii:04 lan4: phylink_mac_config: mode=phy/gmii/Unknown/Unknown adv=000,00000000,00000000 pause=00 link=0 an=0
Aug 25 23:03:55 sw-dsl kernel: [    7.107084] mv88e6085 f1072004.mdio-mii:04: p1: dsa_port_phylink_mac_config()
Aug 25 23:03:55 sw-dsl kernel: [    7.118831] 8021q: adding VLAN 0 to HW filter
on device lan4
Aug 25 23:03:55 sw-dsl kernel: [    7.153604] brdsl: port 3(eno2) entered blocking state
Aug 25 23:03:55 sw-dsl kernel: [    7.153610] brdsl: port 3(eno2) entered disabled state
Aug 25 23:03:55 sw-dsl kernel: [    7.153720] mv88e6085 f1072004.mdio-mii:04 lan2: phy link down gmii/Unknown/Unknown/off
Aug 25 23:03:55 sw-dsl kernel: [    7.153790] device eno2 entered promiscuous mode
Aug 25 23:03:55 sw-dsl kernel: [    7.153890] brdsl: port 3(eno2) entered blocking state
Aug 25 23:03:55 sw-dsl kernel: [    7.153895] brdsl: port 3(eno2) entered forwarding state
Aug 25 23:03:55 sw-dsl kernel: [    7.153930] IPv6: ADDRCONF(NETDEV_CHANGE): brdsl: link becomes ready
Aug 25 23:03:55 sw-dsl kernel: [    7.295739] mv88e6085 f1072004.mdio-mii:04 lan4: phy link down gmii/Unknown/Unknown/off
Aug 25 23:03:55 sw-dsl kernel: [    7.575615] mv88e6085 f1072004.mdio-mii:04 lan1: configuring for phy/gmii link mode
Aug 25 23:03:55 sw-dsl kernel: [    7.575622] mv88e6085 f1072004.mdio-mii:04 lan1: config interface gmii
Aug 25 23:03:55 sw-dsl kernel: [    7.575630] mv88e6085 f1072004.mdio-mii:04 lan1: phylink_mac_config: mode=phy/gmii/Unknown/Unknown adv=000,00000000,00000000 pause=00 link=0 an=0
Aug 25 23:03:55 sw-dsl kernel: [    7.575634] mv88e6085 f1072004.mdio-mii:04: p4: dsa_port_phylink_mac_config()
Aug 25 23:03:55 sw-dsl kernel: [    7.579334] 8021q: adding VLAN 0 to HW filter
on device lan1
Aug 25 23:03:55 sw-dsl kernel: [    7.635966] mv88e6085 f1072004.mdio-mii:04 lan1: phy link down gmii/Unknown/Unknown/off

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!