On Wed, May 23, 2007 at 09:03:02PM -0700, Christoph Lameter wrote: > On Thu, 24 May 2007, Paul Mackerras wrote: > > Also there is the problem that some drivers use ZONE_DMA allocations > > because their device can only generate addresses below some limit, but > > on a platform with an IOMMU there is in fact no restriction on what > > memory the device can access. > > That problem is to some extend addressed by switching ZONE_DMA off which > results in GFP_DMA becoming meaningless. And if GFP_DMA and ZONE_DMA is > gone from a platform then the MAX_DMA_ADDRESS inconsistencies are solved > since the cause of the inconsistencies has evaporated.
Suffice it to say then that with this approach ARM will _never_ be able to have ZONE_DMA turned off, even on platforms where there are no DMA restrictions. I guess that's something we'll just have to live with. -- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
