On Wed, Sep 30, 2020 at 06:39:18PM +0200, Paul Cercueil wrote: >> dma_alloc_pages gives you cached memory, so you can't just use an >> uncached protection for the userspace mmap here. If you want uncached >> memory you need to use dma_alloc_coherent paired with dma_mmap_coherent. >> Or dma_alloc_wc for a slightly different flavor of uncached. (both >> of the map to dma_alloc_attrs / dma_mmap_attrs eventually). > > I don't want uncached memory, I want non-coherent cached memory. We don't have such a thing in the Linux API at all.
