LXT972 FEC problem on MPC855

Ricardo Scop scop at digitel.com.br
Tue Aug 27 08:34:24 EST 2002


Maybe I have a contribution...

On Monday 26 August 2002 18:32, Xiaogeng (Shawn) Jin wrote:
> > You are passing bad/insufficient boot arguments to the Linux  kernel;
> > unfortunaltely you don;t show us this part of the boot messages, so I
> > cannot even guess what you're doing wrong.
> Finally I figured out the problem and solved it. The problem is that the
> kernel didn't get the LINK status correctly. The 'fep->link' was always
> 0 which means the link is down or autonegotiation is in progress.
> In the code which defines 'phy_info_lxt971', it says that somehow LXT971
> tells me that the link is down when the first read after power-up. So
> you have to read MII_REG_SR to set 'fep->phy_status' accordingly. But in
> my case, the read action occurred too early to wait till the link is up.
> So what I did is to delay 5s before reading MII_REG_SR during opening
> FEC device. I guess it takes the link a while to autonegotiate the speed.

Hmm. I suppose PHY should interrupt when link status change, and therefore
phy_status would be updated accordingly. So, maybe you have a problem with
your board's PHY interrupt signal.

Hope this helps.


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