Hi, I noticed using dma_mmap_coherent() on pages allocated via dma_alloc_coherent() results in a warning on x86: map pfn RAM range req uncached-minus for [mem 0x21d500000-0x21d51ffff], got write-back which comes from arch/x86/mm/pat.c. Looking at the code, it seems that dma_mmap_coherent() blindly assumes that the pages are with pgprot_noncached(), but on x86, it's obviously not. Maybe some other archs have the same problem. How should we fix this? Defining a new pgprot_xxx(), and falling back to pgprot_noncached if undefined? Or is it just x86 and do it only there? thanks, Takashi -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>