Messages in this thread | | | Date | Wed, 17 Jun 2009 08:58:19 +0100 | From | Chris Pringle <> | Subject | Re: PowerPC PCI DMA issues (prefetch/coherency?) |
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> You could enable CONFIG_NOT_COHERENT_CACHE. > I've just tried this (I had to edit Kconfig in power/platforms to make the build system accept it), and interestingly it's making no difference. I'm using streaming mappings, and are using the pci_map_sg functions to ensure the memory is mapped/flushed correctly. I've also explicitly put in a pci_dma_sync_sg_for_device, however that's also not made any difference. Turning the cpu cache snoop off has the same affect as it did without CONFIG_NOT_COHERENT_CACHE; it gets much worse. Any other ideas?
Will back off the low latency patches next, and give 2.6.30 a try - see if that makes any difference.
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