[PATCH v3 i-g-t 13/15] lib/i915: Add helper for non-destructive engine property updates

[John.C.Harrison@xxxxxxxxx]

From: John Harrison <John.C.Harrison@xxxxxxxxx>

Various tests want to configure engine properties such as pre-emption
timeout and heartbeat interval. Some don't bother to restore the
original values again afterwards. So, add a helper to make it easier
to do this.

v2: Fix for platforms with no pre-emption capability.

Signed-off-by: John Harrison <John.C.Harrison@xxxxxxxxx>
---
 lib/i915/gem_engine_topology.c | 46 ++++++++++++++++++++++++++++++++++
 lib/i915/gem_engine_topology.h |  9 +++++++
 2 files changed, 55 insertions(+)

diff --git a/lib/i915/gem_engine_topology.c b/lib/i915/gem_engine_topology.c
index 729f42b0a..bd12d0bc9 100644
--- a/lib/i915/gem_engine_topology.c
+++ b/lib/i915/gem_engine_topology.c
@@ -488,6 +488,52 @@ int gem_engine_property_printf(int i915, const char *engine, const char *attr,
 	return ret;
 }
 
+/* Ensure fast hang detection */
+void gem_engine_properties_configure(int fd, struct gem_engine_properties *params)
+{
+	int ret;
+	struct gem_engine_properties write = *params;
+
+	ret = gem_engine_property_scanf(fd, write.engine->name,
+					"heartbeat_interval_ms",
+					"%d", &params->heartbeat_interval);
+	igt_assert_eq(ret, 1);
+
+	ret = gem_engine_property_printf(fd, write.engine->name,
+					 "heartbeat_interval_ms", "%d",
+					 write.heartbeat_interval);
+	igt_assert_lt(0, ret);
+
+	if (gem_scheduler_has_preemption(fd)) {
+		ret = gem_engine_property_scanf(fd, write.engine->name,
+						"preempt_timeout_ms",
+						"%d", &params->preempt_timeout);
+		igt_assert_eq(ret, 1);
+
+		ret = gem_engine_property_printf(fd, write.engine->name,
+						 "preempt_timeout_ms", "%d",
+						 write.preempt_timeout);
+		igt_assert_lt(0, ret);
+	}
+}
+
+void gem_engine_properties_restore(int fd, const struct gem_engine_properties *saved)
+{
+	int ret;
+
+	ret = gem_engine_property_printf(fd, saved->engine->name,
+					 "heartbeat_interval_ms", "%d",
+					 saved->heartbeat_interval);
+	igt_assert_lt(0, ret);
+
+	if (gem_scheduler_has_preemption(fd)) {
+		ret = gem_engine_property_printf(fd, saved->engine->name,
+						 "preempt_timeout_ms", "%d",
+						 saved->preempt_timeout);
+		igt_assert_lt(0, ret);
+	}
+}
+
 uint32_t gem_engine_mmio_base(int i915, const char *engine)
 {
 	unsigned int mmio = 0;
diff --git a/lib/i915/gem_engine_topology.h b/lib/i915/gem_engine_topology.h
index 4cfab560b..b413aa8ab 100644
--- a/lib/i915/gem_engine_topology.h
+++ b/lib/i915/gem_engine_topology.h
@@ -115,6 +115,15 @@ struct intel_execution_engine2 gem_eb_flags_to_engine(unsigned int flags);
 	     ((e__) = intel_get_current_physical_engine(&i__##e__)); \
 	     intel_next_engine(&i__##e__))
 
+struct gem_engine_properties {
+	const struct intel_execution_engine2 *engine;
+	int preempt_timeout;
+	int heartbeat_interval;
+};
+
+void gem_engine_properties_configure(int fd, struct gem_engine_properties *params);
+void gem_engine_properties_restore(int fd, const struct gem_engine_properties *saved);
+
 __attribute__((format(scanf, 4, 5)))
 int gem_engine_property_scanf(int i915, const char *engine, const char *attr,
 			      const char *fmt, ...);
-- 
2.25.1