On Fri, 19 Mar 2010, Catalin Marinas wrote: > On Fri, 2010-03-19 at 17:59 +0000, Nicolas Pitre wrote: > > On Fri, 19 Mar 2010, Russell King - ARM Linux wrote: > > > > > On Fri, Mar 19, 2010 at 09:17:19AM -0400, Nicolas Pitre wrote: > > > > And in this case, the same SATA driver is used on two different system, > > > > one being ARMv5 with absolutely no issues with highmem, and the other > > > > being ARMv6 with highmem problems. So that pretty much rules out IDE > > > > driver bugs. > > > > > > No it doesn't - there's more changes between ARMv5 and ARMv6 than just > > > the cache model. There's weak memory ordering effects too. > > > > Sure. But at the moment we have: > > > > - ARMv5 without highmem -> works > > > > - ARMv5 with highmem -> works > > > > - ARMv6 without highmem -> works > > > > - ARMv6 with highmem -> fails > > > > In all four cases the SATA driver, the hard disk and the filesystem on > > it are identical. In the two ARMv5 cases the system and the kernel are > > identical. Ditto for the two ARMv6 cases. > > Which ARMv6 processor is this? Marvell 88AP510 aka Dove. But the same issue was reported on OMAP. > Is the SATA driver using DMA (I think I read this in the thread but it > started as MMC issues and got confused)? Any block device using DMA is affected. Drivers using PIO are not, neither is NFS. And again, using the _same_ kernel with mem=512m so to be sure highmem doesn't kick in exhibits no issue even with DMA. Nicolas -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
