On Thu, 09 Oct 2008 16:05:57 -0700 Yinghai Lu <yinghai@xxxxxxxxxx> wrote: > Grant Grundler wrote: > > On Thu, Oct 09, 2008 at 02:51:32PM -0700, Yinghai Lu wrote: > >> On Thu, Oct 9, 2008 at 2:35 PM, Matthew Wilcox <matthew@xxxxxx> wrote: > >>> Why's that interesting to the sysadmin of the machine? To the driver > >>> writer, certainly. But what's the use of it to the people using the > >>> machine? > > ... > >> make linux kernel act like black box as other os? > > > > I don't understand your reply. > > If someone thinks linux is a black box, printing this message won't help them. > > > could find out easily why some driver doesn't set dma mask correctly. > like why > qlogic qla2xxx only set consistent to 64bit, > emulex lpfc not set consistent to 64bit IIRC, except for one SGI architecture, coherent_dma_mask is meaningless, dma_mask is always equal to coherent_dma_mask. Lots of IOMMU implementations ignore coherent_dma_mask and use dma_mask for alloc_coherent(). Some drivers doesn't set up coherent_dma_mask. Theoretically, we need to fix this but it doesn't cause any problem. That's why nobody cares about it, I guess. -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
