[Intel-gfx] [PATCH] drm/i915/selftests: Disable iommu for the mock device

[Chris Wilson]

On some machines, the iommu cannot allocate a domain for the mock device
causing the dma_map_sg() to fail, and the selftest to fail with -ENOMEM.
For the mock selftests, we are using a fake device and do not care about
iommu; so convince intel_iommu to treat us as a dummy device with an
identity mapping (and no iommu domain).

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=101080
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/selftests/mock_gem_device.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/i915/selftests/mock_gem_device.c b/drivers/gpu/drm/i915/selftests/mock_gem_device.c
index 678723430d78..38ed006be5be 100644
--- a/drivers/gpu/drm/i915/selftests/mock_gem_device.c
+++ b/drivers/gpu/drm/i915/selftests/mock_gem_device.c
@@ -146,6 +146,9 @@ struct drm_i915_private *mock_gem_device(void)
 	dev_set_name(&pdev->dev, "mock");
 	dma_coerce_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
 
+	/* hack to disable iommu for the fake device; force identity mapping */
+	pdev->dev.archdata.iommu = (void *)-1;
+
 	dev_pm_domain_set(&pdev->dev, &pm_domain);
 	pm_runtime_enable(&pdev->dev);
 	pm_runtime_dont_use_autosuspend(&pdev->dev);
-- 
2.14.1