Link up/down messages from 5200 ethernet driver

[Jon Smirl]

On 12/6/07, Grant Likely <grant.likely at secretlab.ca> wrote:
> On 12/5/07, Jon Smirl <jonsmirl at gmail.com> wrote:
> > On 12/6/07, Jon Smirl <jonsmirl at gmail.com> wrote:
> > > On 12/5/07, Grant Likely <grant.likely at secretlab.ca> wrote:
> > > > On 12/5/07, Jon Smirl <jonsmirl at gmail.com> wrote:
> > > > > Why does the fec5200 driver sometimes not print 'PHY' correctly?
> > > > >
> > > > > phyCORE-MPC5200B-tiny login: TؤV� f0003000:10 - Link is Down
> > > > > T�Y: f0003000:10 - Link is Up - 100/Full
> > > > > T�Y: f0003000:10 - Link is Down
> > > > > PHY: f0003000:10 - Link is Up - 100/Full
> > > >
> > > > Weird; that line comes from drivers/net/phy/phy.c in
> > > > phy_print_status(), and it's just a a pr_info statement.  I suppose it
> > > > might be a stack overrun, but I'd expect more severe symptoms if that
> > > > was the case.
> > > >
> > > > That *looks* like a serial stream corruption.  Is that the output of
> > > > your serial port?  Does dmesg show the same corruption?
> > >
> > > That's the serial port output.
> > > dmesg is ok.
> > >
> > > Nothing else I do can mess up the serial port.
> >
> > Maybe the KERN_INFO prefix is sending out control characters that mess
> > up the serial output?
>
> More likely the Ethernet link state change is interfering with the
> serial line at the electrical level.  Try tweaking the serial clock up
> or down a tiny bit, that might make it more stable.  (I've had to do
> that on one of my boards here to get stable serial output).

That appears to be the problem. It's my Efika that is corrupting the
message. On the Efika Ethernet and serial are right next to each
other. My Phytec system is ok, serial and Ethernet are at opposite
ends of the board.

>
> Cheers,
> g.
>
>
> --
> Grant Likely, B.Sc., P.Eng.
> Secret Lab Technologies Ltd.
> grant.likely at secretlab.ca
> (403) 399-0195
>


-- 
Jon Smirl
jonsmirl at gmail.com