[igt-dev] [PATCH i-g-t] i915/gem_ctx_param: Keep the engine active while peeking at vm layout

[Chris Wilson]

The implicit soft-pinning we use to probe the vm layout using execbuf,
depends on the batch remaining active (not retired) between execbufs.
Naturally, if the background retire worker runs the batch is retired and
the implicit soft-pinning is free to use a fresh address.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 tests/i915/gem_ctx_param.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/tests/i915/gem_ctx_param.c b/tests/i915/gem_ctx_param.c
index bd1ee3996..63e0db38d 100644
--- a/tests/i915/gem_ctx_param.c
+++ b/tests/i915/gem_ctx_param.c
@@ -161,6 +161,7 @@ static void test_vm(int i915)
 		.param = I915_CONTEXT_PARAM_VM,
 	};
 	uint32_t parent, child;
+	igt_spin_t *spin;
 
 	/*
 	 * Proving 2 contexts share the same GTT is quite tricky as we have no
@@ -177,6 +178,15 @@ static void test_vm(int i915)
 	parent = gem_context_create(i915);
 	child = gem_context_create(i915);
 
+	/* Create a background spinner to keep the engines busy */
+	spin = igt_spin_new(i915);
+	for (int i = 0; i < 16; i++) {
+		spin->execbuf.rsvd1 = gem_context_create(i915);
+		gem_context_set_priority(i915, spin->execbuf.rsvd1, 1023);
+		gem_execbuf(i915, &spin->execbuf);
+		gem_context_destroy(i915, spin->execbuf.rsvd1);
+	}
+
 	/* Using implicit soft-pinning */
 	eb.rsvd1 = parent;
 	batch.offset = nonzero_offset;
@@ -226,6 +236,7 @@ static void test_vm(int i915)
 	gem_context_destroy(i915, child);
 	gem_vm_destroy(i915, arg.value);
 
+	igt_spin_free(i915, spin);
 	gem_sync(i915, batch.handle);
 	gem_close(i915, batch.handle);
 }
-- 
2.24.0