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

[Donald Becker]

On Wed, 5 Jul 2000, Giuseppe Ciaccio wrote:

> Kernel is 2.2.16.  Driver is compiled in the kernel (no module).
> 
> NICs are 3COM 3c905C.
> Three kind of networks:
> 	crossover cable,
> 	repeater hub,
> 	Intel Express 510T 100base-TX switch (flow control DISABLED!!!).
> 
> Boot-time probe message:
> 3c59x.c:v0.99H 27May00 Donald Becker http://cesdis.gsfc.nasa.gov/linux/drivers/v
> ortex.html

That message implies that this is my current driver version.  It is not --
it's based on a version over a year old.  One that predates the Tornado.

> eth1: 3Com 3c905C Tornado at 0xa000,  00:01:02:0d:a7:84, IRQ 5
>   8K byte-wide RAM 5:3 Rx:Tx split, autoselect/Autonegotiate interface.
>   MII transceiver found at address 24, status 782d.

Note the transceiver addrss is 24.


> Switch (N-WAY autoneg enabled):
> mii-diag reports:
> Basic registers of MII PHY #24:  3000 782d 0040 6176 05e1 45e1 0003 0000.
>  Basic mode control register 0x3000: Auto-negotiation enabled.
>  You have link beat, and everything is working OK.
>  Your link partner advertised 45e1: Flow-control 100baseTx-FD 100baseTx 10baseT-
> FD 10baseT, w/ 802.3X flow control.
> 
> (NOTE: the switch advertises flow-ctl although disabled!  A bug in mii-diag?
> A bug in the switch firmware?)

It's not a bug in 'mii-diag'.  Your switch must be advertising full control
even when that feature is disabled.

> 237 packets lost, out of 120219 (loss rate = 2%).

0.2%

> Second scenario:  N-WAY autoneg disabled in both NICs

How did you disable N-Way?  

> Switch (N-WAY autoneg enabled):
> 
> mii-diag reports:
> 
> Basic registers of MII PHY #0:  0000 0000 0000 0000 0000 0000 0000 0000.

This is strange -- the PHY address should be 24.  That was what was
reporting in the detection message above.

Any data interpretation from 'mii-diag' is bogus -- the registers are
reporting all zeros.


Donald Becker				becker@scyld.com
Scyld Computing Corporation		http://www.scyld.com
410 Severn Ave. Suite 210		Beowulf Clusters / Linux Installations
Annapolis MD 21403