On Tue, Nov 30, 2004 at 11:06:44PM +0100, Roger Luethi wrote:

quoted

quoted

Perhaps the via-rhine simply can't send out packets back-to-back and
needs 14 byte times of inter-packet gap.  I couldn't find any stray +2
in the driver anywhere but I'm just checking.

Or the via-rhine driver is not programming one of the registers
proper to get optimal spacing.

As with most Donald Becker drivers, many of the register layouts
are not documented in the sources so it's not possible to just
scan the driver looking for potential problems like this.
For example, maybe the TxConfig register has an "IPG" field but
we'll never know by reading anything in the driver source.

Presumably Donald Becker had only access to the publicly available
documentation at the time which is very incomplete and buggy. What
little time my day job leaves for hacking via-rhine is consumed by the
WOL issues that have come up with 2.6.9+, but if you have a specific
question that can be answered by someone who knows the chip but not
necessarily Linux I can try and poke my contacts.

"Is the hardware capable of sending back-to-back packets (i.e. with
an inter-packet gap of no more than 96 bit times)?"

"Can misprogramming the chip lead to the effect that the inter-packet
gap is never less than 112 bit times?"

Thanks in advance.

Of course, you can always check if VIA's driver has the same issue. If
it doesn't, chances are we can borrow the fix.

Hmm, didn't know they had such a driver.  Where can I find it?


cheers,
Lennert