Re: [PATCH] starfire reads irq before pci_enable_device.

Ion Badulescu
2001-02-09T00:47:48Z

On Thu, 8 Feb 2001, Donald Becker wrote:

> > Or we can just tell people, "hey, don't use this 64-bit PCI card on a real
> > 64-bit system, it's broken by design"? I don't think that's a good
> > solution either.
>
> This is not a 64 bit PCI issue.

I know. It was just an ironic comment: we have a card with a 64-bit PCI
bus, we have a 64-bit system which very likely has some 64-bit PCI slots
on its motherboard, perfect match, right? Well, au contraire, the
performance is going to suck big-time, at least for Rx.

> It is an issue with the protocol
> stack. The IP protocol handling code must expect that the header words
> will be misaligned in some circumstances.

I won't get into this...

> It's amusing that a full receive copy is added without any concern, in
> the same discussion where zero-copy transmit is treated as a holy grail!

Amusing? Maybe. Zerocopy will still help with Tx, and with Rx we're just
trying to contain the damage, *with the existent stack*.

> This might be a transceiver preamble issue with the specific
> transceivers on the recent cards. Debugging this type of problem
> sometimes requires a D-Oscope on the MII data pins.
>
> Normally I would suspect a timing problem with a very fast machine, but
> the Starfire hardware generates its own preamble and clock signals, not
> the driver code.

See my previous mail. It turned out to be just a confused chipset.

Thanks,
Ion

--
It is better to keep your mouth shut and be thought a fool,
than to open it and remove all doubt.