Re: [PATCH] starfire reads irq before pci_enable_device.

Jeff Garzik
2001-02-13T13:07:48Z

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On 12 Feb 2001, Jes Sorensen wrote:
> >>>>> "Gérard" == Gérard Roudier <groudier@club-internet.fr> writes:
> Gérard> In PCI, it is the Memory Write and Invalidate PCI transaction
> Gérard> that is intended to allow core-logics to optimize DMA this
> Gérard> way. For normal Memory Write PCI transactions or when the
> Gérard> core-logic is aliasing MWI to MW, the snooping may well
> Gérard> happen. All that stuff, very probably, varies a lot depending
> Gérard> on the core-logic.
>
> In fact one has to look out for this and disable the feature in some
> cases. On the acenic not disabling Memory Write and Invalidate costs
> ~20% on performance on some systems.

And in another message, On Mon, 12 Feb 2001, David S. Miller wrote:
> 3) The acenic/gbit performance anomalies have been cured
> by reverting the PCI mem_inval tweaks.

Just to be clear, acenic should or should not use MWI?

And can a general rule be applied here? Newer Tulip hardware also
has the ability to enable/disable MWI usage, IIRC.

Jeff