diff options
Diffstat (limited to 'arm-tegra-fix-nouveau-crash.patch')
| -rw-r--r-- | arm-tegra-fix-nouveau-crash.patch | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/arm-tegra-fix-nouveau-crash.patch b/arm-tegra-fix-nouveau-crash.patch new file mode 100644 index 000000000..d1d7c61a6 --- /dev/null +++ b/arm-tegra-fix-nouveau-crash.patch @@ -0,0 +1,64 @@ +From 369971aa0101c4cfb84dacaaaa1b5cc5790c14ff Mon Sep 17 00:00:00 2001 +From: Thierry Reding <treding@nvidia.com> +Date: Wed, 11 Apr 2018 10:34:17 +0200 +Subject: [PATCH] drm/nouveau: tegra: Detach from ARM DMA/IOMMU mapping + +Depending on the kernel configuration, early ARM architecture setup code +may have attached the GPU to a DMA/IOMMU mapping that transparently uses +the IOMMU to back the DMA API. Tegra requires special handling for IOMMU +backed buffers (a special bit in the GPU's MMU page tables indicates the +memory path to take: via the SMMU or directly to the memory controller). +Transparently backing DMA memory with an IOMMU prevents Nouveau from +properly handling such memory accesses and causes memory access faults. + +As a side-note: buffers other than those allocated in instance memory +don't need to be physically contiguous from the GPU's perspective since +the GPU can map them into contiguous buffers using its own MMU. Mapping +these buffers through the IOMMU is unnecessary and will even lead to +performance degradation because of the additional translation. + +Signed-off-by: Thierry Reding <treding@nvidia.com> +--- + drivers/gpu/drm/nouveau/nvkm/engine/device/tegra.c | 19 +++++++++++++++++++ + 1 file changed, 19 insertions(+) + +diff --git a/drivers/gpu/drm/nouveau/nvkm/engine/device/tegra.c b/drivers/gpu/drm/nouveau/nvkm/engine/device/tegra.c +index 1f07999aea1d..ac7706f56f6f 100644 +--- a/drivers/gpu/drm/nouveau/nvkm/engine/device/tegra.c ++++ b/drivers/gpu/drm/nouveau/nvkm/engine/device/tegra.c +@@ -19,6 +19,11 @@ + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER + * DEALINGS IN THE SOFTWARE. + */ ++ ++#if IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU) ++#include <asm/dma-iommu.h> ++#endif ++ + #include <core/tegra.h> + #ifdef CONFIG_NOUVEAU_PLATFORM_DRIVER + #include "priv.h" +@@ -105,6 +110,20 @@ nvkm_device_tegra_probe_iommu(struct nvkm_device_tegra *tdev) + unsigned long pgsize_bitmap; + int ret; + ++#if IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU) ++ if (dev->archdata.mapping) { ++ struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev); ++ ++ arm_iommu_release_mapping(mapping); ++ arm_iommu_detach_device(dev); ++ ++ if (dev->archdata.dma_coherent) ++ set_dma_ops(dev, &arm_coherent_dma_ops); ++ else ++ set_dma_ops(dev, &arm_dma_ops); ++ } ++#endif ++ + if (!tdev->func->iommu_bit) + return; + +-- +2.16.3 + |