Re: [RFC PATCH] dma-iommu: Add iommu_dma_max_mapping_size()

[Christoph Hellwig]

On Tue, May 17, 2022 at 11:40:52AM +0100, Robin Murphy wrote:
> Indeed, sorry but NAK for this being nonsense. As I've said at least once 
> before, if the unnecessary SAC address allocation attempt slows down your 
> workload, make it not do that in the first place. If you don't like the 
> existing command-line parameter then fine, there are plenty of other 
> options, it just needs to be done in a way that doesn't break x86 systems 
> with dodgy firmware, as my first attempt turned out to.

What broke x86?