Old problem still present on 11-ALPHA1 - Pi2

[Bernd Walter]

On Mon, Jul 11, 2016 at 08:28:19PM -0500, Karl Denninger wrote:
> 
> 
> On 7/11/2016 15:58, Bernd Walter wrote:
> > On Mon, Jul 11, 2016 at 12:21:53PM -0500, Karl Denninger wrote:
> >> On 7/11/2016 11:38, Hans Petter Selasky wrote:
> >>> On 07/11/16 18:15, Karl Denninger wrote:
> >>> Did you try to set any media options, like 10MBps instead of 100Mbps ?
> >>>
> >> Yes; it makes no difference.
> >>
> >>> What does ifconfig say?
> >>>
> >>> --HPS
> >> No difference -- both are 100BaseTX connected.
> >>
> >> Machine with the problem:
> >> % ifconfig ue0
> >> ue0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
> >>         options=80009<RXCSUM,VLAN_MTU,LINKSTATE>
> >>         ether b8:27:eb:08:12:1c
> >>         inet 192.168.1.200 netmask 0xffffff00 broadcast 192.168.1.255
> >>         media: Ethernet autoselect (100baseTX <full-duplex>)
> >>         status: active
> >>         nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
> >>
> >>
> >> Machine without:
> >> % ifconfig ue0
> >> ue0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
> >>         options=80009<RXCSUM,VLAN_MTU,LINKSTATE>
> >>         ether b8:27:eb:85:21:de
> >>         inet 192.168.1.214 netmask 0xffffff00 broadcast 192.168.1.255
> >>         media: Ethernet autoselect (100baseTX <full-duplex>)
> >>         status: active
> >>         nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
> >>
> >> The only difference I can see between them is that the one that exhibits
> >> the flapping has vlans defined on the interface (which are working
> >> normally.)
> >>
> >> Current code on both machines:
> >> % uname -v
> >> FreeBSD 11.0-BETA1 #0 r302526: Sun Jul 10 10:39:31 CDT 2016    
> >> karl at NewFS.denninger.net:/pics/CrossBuild/obj/arm.armv6/pics/CrossBuild/src/sys/RPI2
> >>
> >> However, this has been an issue since the first 11-Current builds that
> >> had RPI2 capability in them, so it's not version-dependent either.
> > Sure it is not the board, powersupply, cable or switchport?
> Yes, considering that I have (multiple times) swapped literally
> everything (I have a bunch of PI2s here.)  Just for grins and giggles I
> did it again; swapped in a known working (no problems of this sort)
> board, power supply that was used with it and network cable, and moved
> it to a different switch port.
> 
> The problem is still there.
> 
> It *only* happens if I have the VLANs enabled.  If I am running a single
> network on an interface it's fine.
> > Check if the red power LED on the Raspberry is on - it goes off under
> > a certain supply voltage, although the board contiues to work.
> Uh, the red LED only comes on during the boot sequence until the kernel
> init's the GPIO on FreeBSD.  You're thinking of Linux.  I have a little
> program that runs and slowly blinks the green LED though once started;
> it's purpose is to provide a visible "system is running" indication.

Strange - I'll have to test it, but I could have sworn that the power LED is
independend from the OS.

> > AFAIK all Raspberries have the same ethernet chip.
> > Well - some earlier B (not B+) had used the 9512 instead of the 9514.
> > Doesn't sound very logical if the same driver behaves different.
> > A link down/up isn't something I would expect from the host controller
> > causing this either.
> > I also never had this problem on a Pi2.
> How many people are running three networks (base plus two VLANs) on them?

Not just Pi2 - I wonder how many do VLAN with USB ethernet at all?

> >> I have been unable to find a way to log the *reason* the flap occurs
> >> (e.g. nothing in the logs indicating why it thinks link-sense
> >> disappeared, if it actually thinks it did, or if something in the code
> >> performed what amounted to an interface reset.)
> > Usually it is the PHY (which is integrated into the 9514), that detects
> > and negotiates the link.
> > The PHY runs on it's own internal state machine.
> > The OS just gets informed, so that it can trigger some processing,
> > such as updating the MAC for the negotiated link speed/duplex, logging
> > the event, ...
> I know.
> 
> This has been an issue since the first RPI2 builds with this particular
> configuration -- and still is.  If I could figure out *why* it thinks
> the PHY is going down I could track it down, but there's nothing I can
> find that tells me that.

The strange thing is tha VLANs have nothing to do with the link at all.
The only obvious difference for the PHY is that it may see more traffic
with more LANs.
I currently have no Pi running FreeBSD accessable - I run my 24/7
FreeBSD ARM systems on Wandboards, but you ifconfig doewsn't show any
VLAN offloading capabilities, so not an explanation either.

> Oh, and the switch doesn't think it flapped either (!!); there is
> nothing in the switch log about the link being lost and restored.

So it is the receiver side which has a problem.
I assume if you had packet loss you would have mentioned.
Makes me wonder if this is really a link loss at all and not just
some kind of missinformation.
The PHY status is something, which usually gets polled, so maybe
data corruption at any time may lead to this problem?

-- 
B.Walter <bernd at bwct.de> http://www.bwct.de
Modbus/TCP Ethernet I/O Baugruppen, ARM basierte FreeBSD Rechner uvm.