[alsa-devel] [PATCH] ASoC: omap-pcm: Lower the dma coherent mask to 32bits

[Russell King - ARM Linux]

On Fri, Dec 06, 2013 at 09:12:22AM +0100, Takashi Iwai wrote:
> But, it's still unclear why only get_coherent_dma_mask() takes max_pfn
> into account for the check of dma_to_pfn(dev, mask).
> 
> In dma_supported(), 
> 
> 	unsigned long limit;
> 	limit = dma_to_pfn(dev, mask);
> 	if (limit < arm_dma_pfn_limit)
> 		return 0;
> 
> while in get_coherent_dma_mask(),
> 
> 	unsigned long max_dma_pfn;
> 	max_dma_pfn = min(max_pfn, arm_dma_pfn_limit);
> 	if (dma_to_pfn(dev, mask) < max_dma_pfn)
> 		return 0;
> 
> So, the current code looks to me that the results from
> dma_set_coherent_mask() and the actual allocation may conflict.

I did ask Peter to replace *both* with the same thing.