RE: DMA memory limitation?

> The important thing is that pci_alloc_consistent and the other PCI DMA
> functions work as advertised on IA64.  If you pass NULL to
> pci_alloc_consistent, IA64 should give you an ISA DMA-able 
> address.  If
> you don't, you get a 32-bit PCI DMA address.  Use of GFP_DMA is a
> arch-specific detail, so don't let me confuse you there.

Until recently, on IA-64, pci_alloc_consistent() given a NULL pci_dev would
fault.  It's been fixed in at least the most recent IA-64 patch.
pci_map_single() and pci_map_sg() still have the same problem, as they
dereference pci_dev w/o checking for NULL first.

-- 
Matt Domsch
Sr. Software Engineer
Dell Linux Solutions
www.dell.com/linux
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