[Intel-gfx] [PATCH] drm/i915: Disable semaphore inter-engine sync without timeslicing

[Chris Wilson]

Since the remove of the no-semaphore boosting, we rely on timeslicing to
reorder past inter-dependency hogs across the engines. However, if we
require preemption to support timeslicing, and not all machine support
preemption.

Testcase: igt/gem_exec_schedule/semaphore-codependency # bdw/bsw
Fixes: 18e4af04d218 ("drm/i915: Drop no-semaphore boosting")
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
Cc: Mika Kuoppala <mika.kuoppala at linux.intel.com>
---
 drivers/gpu/drm/i915/gem/i915_gem_context.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
index 900ea8b7fc8f..f5d59d18cd5b 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
@@ -230,7 +230,7 @@ static void intel_context_set_gem(struct intel_context *ce,
 		ce->timeline = intel_timeline_get(ctx->timeline);
 
 	if (ctx->sched.priority >= I915_PRIORITY_NORMAL &&
-	    intel_engine_has_semaphores(ce->engine))
+	    intel_engine_has_timeslices(ce->engine))
 		__set_bit(CONTEXT_USE_SEMAPHORES, &ce->flags);
 }
 
@@ -1969,7 +1969,7 @@ static int __apply_priority(struct intel_context *ce, void *arg)
 {
 	struct i915_gem_context *ctx = arg;
 
-	if (!intel_engine_has_semaphores(ce->engine))
+	if (!intel_engine_has_timeslices(ce->engine))
 		return 0;
 
 	if (ctx->sched.priority >= I915_PRIORITY_NORMAL)
-- 
2.20.1