Re: [PATCH v4 05/16] iommu: Move bus setup to IOMMU device registration
From: Jon Hunter <jonathanh@nvidia.com>
Date: 2022-10-18 06:14:01
Also in:
linux-iommu, linux-tegra, lkml
On 06/10/2022 16:27, Robin Murphy wrote:
quoted hunk ↗ jump to hunk
On 2022-10-06 15:01, Jon Hunter wrote:quoted
Hi Robin, On 15/08/2022 17:20, Robin Murphy wrote:quoted
Move the bus setup to iommu_device_register(). This should allow bus_iommu_probe() to be correctly replayed for multiple IOMMU instances, and leaves bus_set_iommu() as a glorified no-op to be cleaned up next. At this point we can also handle cleanup better than just rolling back the most-recently-touched bus upon failure - which may release devices owned by other already-registered instances, and still leave devices on other buses with dangling pointers to the failed instance. Now it's easy to clean up the exact footprint of a given instance, no more, no less.Since this change, I have noticed that the DRM driver on Tegra20 is failing to probe and I am seeing ... tegra-gr2d 54140000.gr2d: failed to attach to domain: -19 drm drm: failed to initialize 54140000.gr2d: -19 Bisect points to this change and reverting it fixes it. Let me know if you have any thoughts.Oh, apparently what's happened is that I've inadvertently enabled the tegra-gart driver, since it seems that *wasn't* calling bus_set_iommu() before. Looking at the history, it appears to have been that way since c7e3ca515e78 ("iommu/tegra: gart: Do not register with bus"), so essentially that driver has been broken and useless for close to 8 years now :( Given that, I'd be inclined to "fix" it as below, or just give up and delete the whole thing. Thanks, Robin. ----->8-----diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig index 5c5cb5bee8b6..7b3f7fd6e527 100644 --- a/drivers/iommu/Kconfig +++ b/drivers/iommu/Kconfig@@ -230,6 +230,7 @@ config TEGRA_IOMMU_GART bool "Tegra GART IOMMU Support" depends on ARCH_TEGRA_2x_SOC depends on TEGRA_MC + depends on BROKEN select IOMMU_API help Enables support for remapping discontiguous physical memory
Thanks Robin. This works for me. Thierry, Dmitry, we need a fix for v6.1 and so OK with the above? Jon -- nvpublic _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel