On Tue, 2012-07-10 at 17:06 -0600, Shuah Khan wrote: > On Tue, 2012-07-10 at 13:32 -0400, Konrad Rzeszutek Wilk wrote: > > On Tue, Jul 10, 2012 at 10:55:07AM -0600, Shuah Khan wrote: > > > On Mon, 2012-07-09 at 16:25 -0400, Konrad Rzeszutek Wilk wrote: > > > > On Fri, Jul 06, 2012 at 05:06:12PM -0600, Shuah Khan wrote: > > > > > Remove SWIOTLB overflow buffer support and return DMA_ERROR_CODE > > > > > (a value of zero) to make it consistent with iommu implementation > > > > > on Intel, AMD, and swiotlb-xen. > > > > > > > > While this is a good forward step and this needs to be done eventually, > > > > you should first send out patches for the drivers that don't check > > > > for the DMA_ERROR_CODE when doing mapping. In other words for the > > > > drivers that map but don't call dma_mapping_error to check. > > > > > > > > When that is fixed and *all the drivers that don't call > > > > dma_mapping_error > > > > are fixed, then this patch makes sense. > > > > > > The challenge will be catching all the drivers and have confidence that > > > all of them are covered. I will start looking into this to get a feel > > > for how many drivers needs fixing. > > > > I don't know if all is needed. Some of them might be dead or not used > > at all anymore - who knows? This treasure hunt would give a good idea > > of which ones are not using the PCI/DMA API right at least. > > > > If it is say, CONFIG_ISA enabled, well, we could #ifdef the overflow > > buffer in the swiotlb with that option. And then work through fixing > > up those drivers - except that finding folks with that driver to > > see if it works .. yuck.. I do have some few ISA cards and some boxes > > with ISA slots :-) > > Looking at the history CONFIG_ISA was disabled back in 2002 and > CONFIG_ISA_DMA_API was disabled in 2004. Sounds like it will be fun > finding drivers that could fail.
Correction. CONFIG_ISA_DMA_API is made configurable on x86_64 it appears back in 2011. -- Shuah -- 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/
