i915/gem_exec_schedule: Check deps along implicit inter-engine semaphores

Given an implicit semaphore from one engine to the next, check that if
we skip the wait on that semaphore the following batch although
submitted early (as it depends along the single engine timeline) is not
executed ahead of its dependency.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>

1 files changed, 82 insertions, 0 deletions

diff --git a/tests/i915/gem_exec_schedule.c b/tests/i915/gem_exec_schedule.c
index a55b8452..330e8a54 100644
--- a/tests/i915/gem_exec_schedule.c
+++ b/tests/i915/gem_exec_schedule.c
@@ -603,6 +603,86 @@ static void semaphore_resolve(int i915)
 	gem_context_destroy(i915, outer);
 }
 
+static void semaphore_noskip(int i915)
+{
+	const int gen = intel_gen(intel_get_drm_devid(i915));
+	unsigned int engine, other;
+	uint32_t ctx;
+
+	igt_require(gen >= 6); /* MI_STORE_DWORD_IMM convenience */
+
+	ctx = gem_context_create(i915);
+
+	for_each_physical_engine(i915, engine) {
+	for_each_physical_engine(i915, other) {
+		struct drm_i915_gem_exec_object2 obj[3];
+		struct drm_i915_gem_execbuffer2 eb;
+		uint32_t handle, *cs, *map;
+		igt_spin_t *chain, *spin;
+
+		if (other == engine || !gem_can_store_dword(i915, other))
+			continue;
+
+		chain = __igt_spin_new(i915, .engine = engine);
+
+		spin = __igt_spin_new(i915, .engine = other);
+		igt_spin_end(spin); /* we just want its address for later */
+		gem_sync(i915, spin->handle);
+		igt_spin_reset(spin);
+
+		handle = gem_create(i915, 4096);
+		cs = map = gem_mmap__cpu(i915, handle, 0, 4096, PROT_WRITE);
+
+		/* Cancel the following spinner */
+		*cs++ = MI_STORE_DWORD_IMM;
+		if (gen >= 8) {
+			*cs++ = spin->obj[1].offset + offset_in_page(spin->condition);
+			*cs++ = 0;
+		} else {
+			*cs++ = 0;
+			*cs++ = spin->obj[1].offset + offset_in_page(spin->condition);
+		}
+		*cs++ = MI_BATCH_BUFFER_END;
+
+		*cs++ = MI_BATCH_BUFFER_END;
+		munmap(map, 4096);
+
+		/* port0: implicit semaphore from engine */
+		memset(obj, 0, sizeof(obj));
+		obj[0] = chain->obj[1];
+		obj[0].flags |= EXEC_OBJECT_WRITE;
+		obj[1] = spin->obj[1];
+		obj[2].handle = handle;
+		memset(&eb, 0, sizeof(eb));
+		eb.buffer_count = 3;
+		eb.buffers_ptr = to_user_pointer(obj);
+		eb.rsvd1 = ctx;
+		eb.flags = other;
+		gem_execbuf(i915, &eb);
+
+		/* port1: dependency chain from port0 */
+		memset(obj, 0, sizeof(obj));
+		obj[0].handle = handle;
+		obj[0].flags = EXEC_OBJECT_WRITE;
+		obj[1] = spin->obj[1];
+		memset(&eb, 0, sizeof(eb));
+		eb.buffer_count = 2;
+		eb.buffers_ptr = to_user_pointer(obj);
+		eb.flags = other;
+		gem_execbuf(i915, &eb);
+
+		igt_spin_set_timeout(chain, NSEC_PER_SEC / 100);
+		gem_sync(i915, spin->handle); /* To hang unless cancel runs! */
+
+		gem_close(i915, handle);
+		igt_spin_free(i915, spin);
+		igt_spin_free(i915, chain);
+	}
+	}
+
+	gem_context_destroy(i915, ctx);
+}
+
 static void reorder(int fd, unsigned ring, unsigned flags)
 #define EQUAL 1
 {
@@ -1592,6 +1672,8 @@ igt_main
 			semaphore_codependency(fd);
 		igt_subtest("semaphore-resolve")
 			semaphore_resolve(fd);
+		igt_subtest("semaphore-noskip")
+			semaphore_noskip(fd);
 
 		igt_subtest("smoketest-all")
 			smoketest(fd, ALL_ENGINES, 30);