On Dec 12, 2011, at 10:27 PM, Benjamin Herrenschmidt wrote: > On Mon, 2011-12-12 at 21:55 -0600, Becky Bruce wrote: >> 1) dma_direct_alloc_coherent strips GFP_HIGHMEM out of the flags field >> when calling the actual allocator and the iotlb version does not. I >> don't know how much this matters - I did a quick grep and I don't see >> any users that specify that, but somebody went through the trouble of >> putting it in there in the first place and without knowing why I >> wasn't willing to get rid of it. Now, since my patch it looks like >> someone added a VM_BUG_ON into __get_free_pages() if GFP_HIGHMEM so >> this would get caught. However, I don't know if we really want to >> throw a bug there. >> >> 2) The iotlb code doesn't deal with the !coherent parts like 8xx. We >> can work around that by setting up the dma_ops differently for that >> case instead. > > Does the rest of it handle them ? I mean swiotlb_map_sg_attrs etc...
The non-coherent "specialness" is in the dma sync stuff and no, I don't think the iotlb stuff deals with that properly. Do you not have a problem with 1)? If not then I think we can look at switching over; 2) was more of a secondary thing. -B _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev