On Tuesday 13 June 2006 06:49, David Miller wrote: > From: Andi Kleen <[EMAIL PROTECTED]> > Date: Tue, 13 Jun 2006 05:47:49 +0200 > > > I've been playing with the idea of writing "early1394" that just > > turns the DMA controller on as early as possible similar to earlyprintk > > on the target. Then it would be possible to use it for early > > debugging too. But so far it's not done yet. > > Does this raw1394 thing with firescope just assume DMA address == > physical address?
Yes. > How would it work to access all of physical > memory properly on IOMMU platforms? It assumes you don't have an IOMMU - relies on all memory being accessible by ohci1394. On x86-64 it can't access > 4GB also, but that's normally ok because the kernel log buffer is below that. I guess if you use 1394 with remote DMA for other protocols (like video etc.) there must be some way for the subsystem to map the memory even on IOMMU systems. I admit I haven't dived that deeply into the 1394 subsystem so I don't know how that works. -Andi - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html