Re: nfe/PXE problem

> > On Tue, Mar 13, 2007 at 09:10:38AM +0200, Danny Braniss wrote:
> >  > 
> >  > > well, I can PXE boot this box if I use an fxp NIC, with the nfe I tracked the 
> >  > > problem
> >  > > to sys/nfsclient/nfs_diskless, where in nfs_setup_diskless(void)
> >  > > it does not find the nfe interface, ie, something does not match, but the 
> >  > > interface
> >  > > was detected!.
> >  > > i'll try and do some more debugging.
> >  > > 
> >  > ok, I found the problem, in nfs_diskless.c nfs_setup_diskless(),
> >  > there is a loop to search for the interface that was used to boot from,
> >  > and no match is found because the hadrware ethernet address
> >  > in the nfe is in the wrong byte order! and so the bcmp(...) fails.
> > 
> > Good catch!
> > 
> >  > Interestingly, if booting NOT via PXE the Ethernet address is OK!
> >  > 
> >  > nfe0: <NVIDIA nForce 430 MCP13 Networking Adapter> port 0xdc00-0xdc07 mem 
> >  > 0xfe02c000-0xfe02cfff irq 22 at device 20.0 on pci0
> >  > 	nfe0: Ethernet address: 00:18:f3:a9:6c:57
> >  > and via PXE:
> >  > 	nfe0: Ethernet address: 57:6c:a9:f3:18:00
> >  > 
> >  > can someone with the right knowledge fix this?
> >  > 
> > 
> > AFAIK there is no known way to get an ethernet address via EEPROM on
> > NVIDIA NIC so nfe(4) reads specific address registers to get ethernet
> > address as a workaround. The address registers are filled
> > automatically by hardware after hardware reset. This type of
> > acquisition of ethernet address is *NOT* correct way as it could get
> > a fake etherent address since adiministor can program other ethernet
> > address into the NIC.(e.g. ifconfig(8) can change ethernet address.)
> > Therefore nfe(4) is very careful to save original ethernet address
> > in device attach phase and restores the ethernet address at device
> > detach time.
> > To make matters worse, it seems that ethernet address in NVIDIA NIC
> > is loaded backwards into registers so nfe(4) corrects it in
> > nfe_init_locked(). However, it seems PXE code does not do necessary
> > swapping for ethernet address and does not restore original MAC
> > address in the end of PXE phase so the NIC will have bogusly
> > programmed MAC address. When kernel boots and nfe(4) is attached it
> > will load the bogus ethernet address which was already programmed by
> > PXE. If /etc/start_if.nfe0 is honored in diskless boot you can override
> > the ethernet address to use the same ethernet address as PXE did.
> > 
> > Even if there is a way to get an ethernet address from EEPROM, PXE
> > should be fixed first since it uses bogus ethernet address in booting
> > stage. If I encounter the same situation I would contact vendor for
> > updated PXE image for the NVIDIA NIC. If that is not available I think
> > the only remaining option would be adding a new tunable to swap the
> > ethernet address.
> > 
> > I'm not familiar with PXE and I din't use PXE for a long time so I
> > could be completely wrong.
> 
> not completely :-)
> the DHCP/PXE boot works with the 'correct ethernet address'.
> this is because I use the static/registered mac, and so a bogus mac address
> can't get past the DHCP/PXE stage.
> so, the PXE is using the correct mac address.
> I can't use /etc/... because of the horse-cart problem, it's booting
> diskless, and the 'disk' is nfs readable via the NIC, but the NIC is not 
> working
> 
> the question now, is to see if the nfe driver can check if it was
> used by the PXE, and flip the address. or have NVIDIA comeup with
> a patch ...

new twist to the Nvidia saga:
the problem (of the inverted mac) happens with the latest bios, a
previous version is ok - unfourtunately, it seems impossible to downgrade.

danny