> I have more information about DMA on the board that I'm using; probably, I > can make dma-contig work with my device.
Ok, the driver STA2X11 now works with a patched dma-contig allocator. So, my streaming allocator it is not mandatory. I based my work on the previous work made by Windriver, but now I understand the DMA problem and the solution easy. I investigated (asked to Alessandro Rubini who worked on this board) about this DMA issue. The problem is that on the sta2x11 architecture only the first 512MB are available through the PCI bus, but the allocator can allocate memory for DMA above this limit. By using GFP_DMA flags the allocation take place under the 16MB so it works. If you think that the streaming allocator can be useful for someone else (who has performance problem with uncached DMA like Jonathan when he did dma-nc allocator), I can resend the patch. I cannot do performance test at the moment because I don't have the time, so I cannot personally justify the presence of a new allocator. I think that I will do some performance test with this driver; if I will find that dma-streaming works better I will propose it again. I will propose V4 patches soon. -- Federico Vaga -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
