[vortex] 3c905C: Packet losses (a more precise description)

[Andrew Morton]

Giuseppe Ciaccio wrote:
> 
> I use the 3c90xcfg.exe DOS utility shipped together the NIC.
> With such utility, I can disable the autoneg.
> Then, I reboot with Linux and get the above.

I see.  EEPROM settings.  Thanks.

> > > ...
> > > This means that the 3c905C adapters will however use flow ctl when connected
> > > by a crossover cable.  Since there is no packet loss in this case,
> > > the faulty device must be the switch.
> >
> > The 3c905 never generates flow control frames - this is a driver
> > responsibility and the Linux drivers don't do it.
> >
> > With the driver you have, an incoming flow control frame will be
> > either discarded due to a filtered-out MAC address, or dropped
> > on the floor by the networking code due to unrecognised ethertype.
> 
> Driver responsibility ?!?  I was pretty sure 802.3x STOP-GO packets
> were hardware-managed.  I'm sure it is so with the Alteon AceNIC
> Gigabit Eth card, and thought it was the same with all other 802.3x-capable
> devices.

That's my understanding.  The 3c905C will recognise and act upon
incoming PAUSE frames if programmed to do so.  But it won't generate
outgoing ones in hardware (pretty sure of this).  This is presumably why
the datasheet rabbits on so much about how to put packets into the
_head_ of the outgoing DPD list.