Re: [PATCH] starfire reads irq before pci_enable_device.

[Alan Cox]

> > 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...)

DMA to main memory normally invalidates those lines in the CPU cache rather
than the cache snooping and updating its view of them.