Re: PCI MMIO flushing and stuff (was Re: 2.2.15 with eepro100: eth0:

From: Alan Cox (alan@lxorguk.ukuu.org.uk)
Date: Sun May 21 2000 - 08:50:55 EDT

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> > > What happens when PCI DMA writes to an address which is currently clean
> > > within a CPU cache?
> >
> > It goes dirty
>
> Are you sure? It should be invalidated shouldn't it?

It depends how smart the CPU/Bus is and if the line is clean but exclusive.
I dont know if x86 supports it but in this case the CPU can steal the
transaction and write it to cache taking the line dirty but still exclusive

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