Messages in this thread | | | From | Manuel Lauss <> | Date | Wed, 26 Jun 2019 09:16:46 +0200 | Subject | Re: [PATCH] au1200fb: don't use DMA_ATTR_NON_CONSISTENT |
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On Tue, Jun 25, 2019 at 2:13 PM Christoph Hellwig <hch@lst.de> wrote: > > au1200fb allocates DMA memory using DMA_ATTR_NON_CONSISTENT, but never > calls dma_cache_sync to synchronize the memory between the CPU and the > device. If it was use on a not cache coherent bus that would be fatal, > but as far as I can tell from the naming and the mips platform > implementation it always is used in cache coherent systems. Remove > the DMA_ATTR_NON_CONSISTENT flag, which is a no-op in that case.
Very early au1200 chips, on which this driver apparently was developed on, had issues with cache coherency, but this was fixed in a later step, none of the 3 steppings I have access to exhibit any problems with this patch applied.
> Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-By: Manuel Lauss <manuel.lauss@gmail.com>
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