Hi Russell, On 5/25/2017 8:35 PM, Russell King - ARM Linux wrote: > On Wed, May 24, 2017 at 02:26:13PM +0300, Laurent Pinchart wrote: >> Again, the patch I propose is the simplest v4.12-rc fix I can think of, short >> of reverting your complete IOMMU probe deferral patch series. Let's focus on >> the v4.12-rc fix, and then discuss how to move forward in v4.13 and beyond. > > Except, I don't think it fixes the problem that Sricharan is trying to > fix, namely that of DMA ops that have been setup, torn down, and are > trying to be re-setup again. The issue here is that results in a stale > setup, because the dma_ops are left in-place from the first iommu setup, > but the iommu mapping has been disposed of. > > Your patch only avoids the problem of tearing down someone else's DMA > ops. We need a combination of both patches together. > > What needs to happen for Sricharan's problem to be resolved is: > > 1. move all of __arm_iommu_detach_device() into arm_iommu_detach_device(). > 2. replace the __arm_iommu_detach_device() call in arm_teardown_iommu_dma_ops() > with arm_iommu_detach_device(). > > as I don't see any need to have a different order in > arm_teardown_iommu_dma_ops(). > Right, both patches are required and i was also thining the same thing about using arm_iommu_detach_device from arm_teardown_iommu_dma_ops instead. Will repost with this. Regards, Sricharan -- "QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
