Re: [PATCH v2 2/2] dma-contiguous: Use fallback alloc_pages for single pages

From: Christoph Hellwig
Date: Tue Aug 27 2019 - 07:55:48 EST

On Tue, Aug 27, 2019 at 06:03:14PM +0900, Masahiro Yamada wrote:
> Yes, this makes my driver working again
> when CONFIG_DMA_CMA=y.
> If I apply the following, my driver gets back working
> irrespective of CONFIG_DMA_CMA.

That sounds a lot like the device simply isn't 64-bit DMA capable, and
previously always got CMA allocations under the limit it actually
supported. I suggest that you submit this quirk to the mmc maintainers.