From 5ca2110ba5e3f8fb8b548721b0db01bae6545be3 Mon Sep 17 00:00:00 2001 From: Robin Murphy Date: Thu, 20 Oct 2022 15:23:40 +0100 Subject: [PATCH] gpu: host1x: Avoid trying to use GART on Tegra20 [ Upstream commit c2418f911a31a266af4fbaca998dc73d3676475a ] Since commit c7e3ca515e78 ("iommu/tegra: gart: Do not register with bus") quite some time ago, the GART driver has effectively disabled itself to avoid issues with the GPU driver expecting it to work in ways that it doesn't. As of commit 57365a04c921 ("iommu: Move bus setup to IOMMU device registration") that bodge no longer works, but really the GPU driver should be responsible for its own behaviour anyway. Make the workaround explicit. Reported-by: Jon Hunter Suggested-by: Dmitry Osipenko Signed-off-by: Robin Murphy Tested-by: Jon Hunter Signed-off-by: Thierry Reding Signed-off-by: Sasha Levin --- drivers/gpu/drm/tegra/drm.c | 4 ++++ drivers/gpu/host1x/dev.c | 4 ++++ 2 files changed, 8 insertions(+) diff --git a/drivers/gpu/drm/tegra/drm.c b/drivers/gpu/drm/tegra/drm.c index 611cd8dad46ed..4f5affdc60807 100644 --- a/drivers/gpu/drm/tegra/drm.c +++ b/drivers/gpu/drm/tegra/drm.c @@ -1083,6 +1083,10 @@ static bool host1x_drm_wants_iommu(struct host1x_device *dev) struct host1x *host1x = dev_get_drvdata(dev->dev.parent); struct iommu_domain *domain; + /* Our IOMMU usage policy doesn't currently play well with GART */ + if (of_machine_is_compatible("nvidia,tegra20")) + return false; + /* * If the Tegra DRM clients are backed by an IOMMU, push buffers are * likely to be allocated beyond the 32-bit boundary if sufficient diff --git a/drivers/gpu/host1x/dev.c b/drivers/gpu/host1x/dev.c index fc9f54282f7d6..c2a4bf2aae615 100644 --- a/drivers/gpu/host1x/dev.c +++ b/drivers/gpu/host1x/dev.c @@ -204,6 +204,10 @@ static void host1x_setup_sid_table(struct host1x *host) static bool host1x_wants_iommu(struct host1x *host1x) { + /* Our IOMMU usage policy doesn't currently play well with GART */ + if (of_machine_is_compatible("nvidia,tegra20")) + return false; + /* * If we support addressing a maximum of 32 bits of physical memory * and if the host1x firewall is enabled, there's no need to enable -- 2.30.2