Re: [PATCH] starfire reads irq before pci_enable_device.

Ion Badulescu (ionut@cs.columbia.edu)
Fri, 9 Feb 2001 15:32:35 -0800 (PST)


On Fri, 9 Feb 2001, Alan Cox wrote:

> > 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!
>
> For non routing paths its virtually free because the DMA forced the lines
> from cache anyway.

Are you actually sure about this? I thought DMA from PCI devices reached
the main memory without polluting the L2 cache. Otherwise any large DMA
transfer would kill the cache (think frame grabbers...)

Ion

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

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