problem with blk_queue_bounce_limit()

From: Christoph Hellwig <[email protected]>
Date: Fri, 6 Jun 2003 08:44:10 +0100

PCI_DMA_BUS_IS_PHYS should be a propert of each struct device because a machine might have a iommu for one bus type but not another,

We know of no such systems. Even in mixed-bus environments such as sparc64 SBUS+PCI systems.

Actually, I know of such a system, although, I will admit they're obscure. Certain PA-RISC machines with EISA buses have an IOMMU on the EISA bus alone (not on the GSC bus). It's job was really to cope with the ISA DMA issue nicely, but it qualifies.

It was for machines like this that I've already been thinking about introducing a dma_is_phys(dev) macro, which I originally left out of the generic device DMA API.

James