8.1 xl + dual-speed Netgear hub = yoyo

[perryh at pluto.rain.com]

Damien Fleuriot <ml at my.gd> wrote:
> On 10/21/11 5:00 PM, perryh at pluto.rain.com wrote:
> > I have an 8.1-RELEASE system with an xl on the mainboard:
> >   xl0: <3Com 3c905C-TX Fast Etherlink XL> port 0xdc80-0xdcff mem 0xf8fffc00-0xf8fffc7f irq 16 at device 4.0 on pci2
> >   miibus0: <MII bus> on xl0
> >   xlphy0: <3c905C 10/100 internal PHY> PHY 24 on miibus0
> >   xlphy0:  10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto
> >   xl0: Ethernet address: 00:b0:d0:22:5a:14
> >   xl0: [ITHREAD]
> > It has been working properly while connected to an old 10-BaseT
> > hub, but when I moved it to a (not as old) Netgear 10/100 dual-
> > speed hub the link started to yo-yo:
>
> Pray tell, what's a "dual-speed hub" , marketing mumbo-jumbo ?

That's what Netgear calls it :)

> If that's a hub that supports negotiation of different speeds
> (10 vs 100), then yes, I call that marketing mumbo-jumbo ;)

It supports negotiation of either 10 or 100 on each port
independently, so it must internally have a 2-port switch
between the 10- and 100- sides.  "10/100 dual-speed hub"
seems more compact than "marketing mumbo-jumbo hub" :)

> >   Oct 21 07:16:00 fbsd81 kernel: xl0: link state changed to DOWN
> >   Oct 21 07:16:02 fbsd81 kernel: xl0: link state changed to UP
> >   Oct 21 07:16:12 fbsd81 kernel: xl0: link state changed to DOWN
> [snip]
> > Both connections were using the same (short) Cat5 cable, I tried
> > two different ports on the 10/100 hub, and other systems work OK
> > on that 10/100 hub.
> > 
> > How do I get this interface to operate properly at 100MB?
>
> You change your faulty cable and enjoy ;)
> It is totally possible that your cable be the cause, and that it
> can operate just fine at 10MB but not at 100.

I tried a (different) brand-new cable.  Same problem.  I suppose
maybe the xl's 100MB phy is dodgy, but it does work after a fashion
-- some packets do get through during the times when the link is UP.
Anything else to try?