Re: [PATCH 1/4] of/fdt: Update zone_dma_bits when running in bcm2711

[Christoph Hellwig]

On Fri, Oct 09, 2020 at 06:10:52PM +0100, Catalin Marinas wrote:
> kdump wants DMA-able memory and,

DMAable by whom?  The only way to guranteed DMAable memory is to use
the DMA memory allocator(s) and pass a specific device to them.  Everyting
else is just fundamentally broken.  Note that even when device is not
DMAable we can still use swiotlb to access it.