Re: Various 802.1Q VLAN driver patches.

[Patrick Schaaf <bof@bof.de>]

On Fri, Mar 01, 2002 at 02:17:22PM -0500, Jeff Garzik wrote:
> Ben Greear wrote:
> > --- linux-2.4.16/drivers/net/eepro100.c Mon Nov 12 18:47:18 2001
> > +++ linux/drivers/net/eepro100.c        Tue Dec 18 11:36:11 2001
> > @@ -510,12 +510,12 @@
> >   static const char i82557_config_cmd[CONFIG_DATA_SIZE] = {
> >          22, 0x08, 0, 0,  0, 0, 0x32, 0x03,  1, /* 1=Use MII  0=Use AUI */
> >          0, 0x2E, 0,  0x60, 0,
> > -       0xf2, 0x48,   0, 0x40, 0xf2, 0x80,              /* 0x40=Force full-duplex */
> > +       0xf2, 0x48,   0, 0x40, 0xfa, 0x80,              /* 0x40=Force full-duplex */
> >          0x3f, 0x05, };
> >   static const char i82558_config_cmd[CONFIG_DATA_SIZE] = {
> >          22, 0x08, 0, 1,  0, 0, 0x22, 0x03,  1, /* 1=Use MII  0=Use AUI */
> >          0, 0x2E, 0,  0x60, 0x08, 0x88,
> > -       0x68, 0, 0x40, 0xf2, 0x84,              /* Disable FC */
> > +       0x68, 0, 0x40, 0xfa, 0x84,              /* Disable FC */
> >          0x31, 0x05, };
> 
> hmmm. hmmm. hmmm.
> 
> I am sorely tempted to drop this patch, simply because it's changing one
> magic number to another.  One key question I have is, what the fsck does
> this patch really do???  If it turns on VLAN [de-]tagging
> unconditionally, for example, that's unacceptable.

This patch, from all I know using it, does exactly one thing: it permits
receiving (and sending) slightly larger frames, for setting the MTU on the
base interface to 1504, so the VLAN interfaces themselves can run the
normal 1500 byte MTU.

I have been using the patch to this end on several eepro100 based systems,
over the last year, with no surprises.

I agree that such an array of magic constants is very very undesirable.

best regards
  Patrick