[Intel-gfx] [PATCH 07/27] drm/i915/guc: Don't call switch_to_kernel_context with GuC submission

[Matthew Brost]

Calling switch_to_kernel_context isn't needed if the engine PM reference
is taken while all contexts are pinned. By not calling
switch_to_kernel_context we save on issuing a request to the engine.

v2:
 (Daniel Vetter)
  - Add FIXME comment about pushing switch_to_kernel_context to backend

Signed-off-by: Matthew Brost <matthew.brost at intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>
---
 drivers/gpu/drm/i915/gt/intel_engine_pm.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/gpu/drm/i915/gt/intel_engine_pm.c b/drivers/gpu/drm/i915/gt/intel_engine_pm.c
index 1f07ac4e0672..11fee66daf60 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_pm.c
+++ b/drivers/gpu/drm/i915/gt/intel_engine_pm.c
@@ -162,6 +162,15 @@ static bool switch_to_kernel_context(struct intel_engine_cs *engine)
 	unsigned long flags;
 	bool result = true;
 
+	/*
+	 * No need to switch_to_kernel_context if GuC submission
+	 *
+	 * FIXME: This execlists specific backend behavior in generic code, this
+	 * should be pushed to the backend.
+	 */
+	if (intel_engine_uses_guc(engine))
+		return true;
+
 	/* GPU is pointing to the void, as good as in the kernel context. */
 	if (intel_gt_is_wedged(engine->gt))
 		return true;
-- 
2.32.0