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

From: Masahiro Yamada
Date: Wed Aug 28 2019 - 06:54:37 EST

Hi Christoph,

On Tue, Aug 27, 2019 at 8:55 PM Christoph Hellwig <hch@xxxxxx> wrote:
> 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.

I tested v5.2 and my MMC host controller works with
dma_address that exceeds 32-bit physical address.

So, I believe my MMC device is 64-bit DMA capable.

I am still looking into the code
to find out what was changed.

Best Regards
Masahiro Yamada