On Mon, Feb 11, 2019 at 04:27:40PM +0100, Stefan Wahren wrote: > >> All my results refers to the mainline kernel we all should talk about. I > >> started a gist which try to describe the mainline variant: > >> https://gist.github.com/lategoodbye/c7317a42bf7f9c07f5a91baed8c68f75 > > So to summarize: > > - Raspberry Pi Foundation kernel works just with RFC series > > - mainline kernel works out of the box > > > > is my understanding correct? > > not really. > > Compiling the mainline kernel with arm/multi_v7_defconfig it works. > Using the same kernel but with arm64/defconfig doesn't work. But i don't > think this is a 32/64 bit issue. The arm64 defconfig is much more > complex (e.g. enables more IOMMU stuff). One possible thing that could be broken with IOMMU is allocating big buffers via page_fraq_alloc(). Theoretically that should work, but who knows. You can check my patch posted recently, it make the driver stop doing big allocations via page_frag_alloc(): https://lore.kernel.org/linux-wireless/1549872974-7268-1-git-send-email-sgruszka@xxxxxxxxxx/ Stanislaw
