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

2023年3月1日 13:06，Christoph Hellwig [off-list ref] 写道：

quoted

- 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.