On Friday 16 January 2015 14:55:45 Will Deacon wrote: > Hi Tom, > > On Fri, Jan 16, 2015 at 02:45:30PM +0000, Tom Lendacky wrote: > > I have tested ACPI-enablement patches for the amd-xgbe/amd-xgbe-phy > > drivers that I'm about to submit upstream with the V7 patch series > > on the AMD Seattle server platform. There does not appear to be support > > for the _CCA attribute in this patch series. The amd-xgbe driver will > > setup the device domain and cache attributes based on the presence of > > this attribute, but it requires the arch support to assign the proper > > DMA operations in order for it to all work correctly. > > > > Overriding the _CCA attribute in the driver, I was able to successfully > > test the driver and this patch series. > > Hopefully this will all be addressed when the IORT parts of ACPI have > settled down (the current proposal allows for these attributes to be > described as well as their interaction with things like IOMMUs). > > In the meantime, are you falling back to non-coherent DMA? If so, what > attributes have you settled on? We need to be really careful not to > corrupt data during cache invalidatation when mapping a non-coherent > buffer for the CPU. I think in case of ACPI we should use cache-coherent as the default, as this is what all servers will use for DMA masters. Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
