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(). -- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up according to speedtest.net. -- 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
