Hello *, Continuing my blind investigation on ccio-dma stuff, I read those 2 different comments: in include/asm-parisc/scatterlist.h, scartterlist structure is defined like this: struct scatterlist { #ifdef CONFIG_DEBUG_SG unsigned long sg_magic; #endif unsigned long page_link; unsigned int offset; unsigned int length; /* an IOVA can be 64-bits on some PA-Risc platforms. */ dma_addr_t iova; /* I/O Virtual Address */ __u32 iova_length; /* bytes mapped */ }; in absolute the comment "an IOVA can be 64-bits on some PA-Risc platforms." seems ok. but otoh, include/asm-parisc/types.h, defined dma_addr_t like this: /* Dma addresses are 32-bits wide. */ typedef u32 dma_addr_t; typedef u64 dma64_addr_t; #endif /* __ASSEMBLY__ */ OK it's just a comment but imho there is interesting matter in x86: typedef u64 dma64_addr_t; #if defined(CONFIG_X86_64) || defined(CONFIG_HIGHMEM64G) /* DMA addresses come in 32-bit and 64-bit flavours. */ typedef u64 dma_addr_t; #else typedef u32 dma_addr_t; #endif But I simply have no idea which "#if defined" would be the most relevant for parisc, any idea? Cheers, r. - To unsubscribe from this list: send the line "unsubscribe linux-parisc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html