Re: [PATCH v2 5/5] of: address: Always use dma_default_coherent for default coherency

[Jiaxun Yang]

> 2023年3月1日 13:06，Christoph Hellwig <hch@xxxxxx> 写道：
> 
>> - select OF_DMA_DEFAULT_COHERENT if !NOT_COHERENT_CACHE
> 
> Doesn't powerpc need to select CONFIG_ARCH_DMA_DEFAULT_COHERENT now,
> or even better should be doing that in the patch adding that
> symbol?

If I read the code correctly for powerpc OF_DMA_DEFAULT_COHERENT is only selected
with !NOT_COHERENT_CACHE, which means non-coherent dma support is disabled….

> 
> In fact I wonder if adding CONFIG_ARCH_DMA_DEFAULT_COHERENT and removing
> OF_DMA_DEFAULT_COHERENT should be one patch, as that seems to bring
> over the intent a little better I'd say.