[igt-dev] [PATCH i-g-t] i915/gem_ctx_engines: Use an offset hint to avoid overlap

[Chris Wilson]

As Braswell is using aliasing-ppgtt, softpinning is trick as we have to
avoid overlapping with HW objects in the GGTT (like context images).
Typically allocations are from either end, so if we provide a hint to
use the middle, we should be safe from overlap.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 tests/i915/gem_ctx_engines.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/tests/i915/gem_ctx_engines.c b/tests/i915/gem_ctx_engines.c
index 1e82e51ee..55794a438 100644
--- a/tests/i915/gem_ctx_engines.c
+++ b/tests/i915/gem_ctx_engines.c
@@ -425,7 +425,10 @@ static void independent(int i915)
 		.value = to_user_pointer(&engines),
 		.size = sizeof(engines),
 	};
-	struct drm_i915_gem_exec_object2 results = { .handle = gem_create(i915, 4096) };
+	struct drm_i915_gem_exec_object2 results = {
+		.handle = gem_create(i915, 4096),
+		.offset = gem_aperture_size(i915) / 2,
+	};
 	const uint32_t bbe = MI_BATCH_BUFFER_END;
 	int timeline = sw_sync_timeline_create();
 	uint32_t last, *map;
-- 
2.24.0