[PATCH] drm/i915/guc: Skip suspend/resume GuC action on platforms w/o GuC submission

[don.hiatt at intel.com]

From: Don Hiatt <don.hiatt at intel.com>

NB: For Trybot only, split out the active submission logic

On some platforms (e.g. KBL) that do not support GuC submission, but
the user enabled the GuC communication (e.g for HuC authentication)
calling the GuC EXIT_S_STATE action results in lose of ability to
enter RC6. We can remove the GuC suspend/resume entirely as we do
not need to save the GuC submission status.

v2: Do not suspend/resume the GuC on platforms that do not support
    Guc Submission.
v3: Fix typo, move suspend logic to remove goto.
v4: XXX -- use guc_submission_active

Signed-off-by: Don Hiatt <don.hiatt at intel.com>
---
 drivers/gpu/drm/i915/gt/uc/intel_guc.c            |  7 +++++++
 drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c |  2 +-
 drivers/gpu/drm/i915/gt/uc/intel_guc_submission.h |  1 +
 drivers/gpu/drm/i915/gt/uc/intel_uc.c             |  8 ++++++++
 drivers/gpu/drm/i915/i915_drv.h                   | 14 ++++++++++++++
 5 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc.c b/drivers/gpu/drm/i915/gt/uc/intel_guc.c
index f12959182182..56ad4a74bb8b 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc.c
@@ -587,6 +587,13 @@ int intel_guc_suspend(struct intel_guc *guc)
 		GUC_POWER_D1, /* any value greater than GUC_POWER_D0 */
 	};
 
+	/*
+	 * If GuC communication is enabled but submission is not supported,
+	 * we do not need to suspend the GuC.
+	 */
+	if (!intel_guc_submission_is_enabled(guc))
+		return 0;
+
 	/*
 	 * The ENTER_S_STATE action queues the save/restore operation in GuC FW
 	 * and then returns, so waiting on the H2G is not enough to guarantee
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
index 2498c55e0ea5..0aaef7c07879 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
@@ -1081,7 +1081,7 @@ static void guc_interrupts_release(struct intel_gt *gt)
 	rps->pm_intrmsk_mbz &= ~ARAT_EXPIRED_INTRMSK;
 }
 
-static void guc_set_default_submission(struct intel_engine_cs *engine)
+void guc_set_default_submission(struct intel_engine_cs *engine)
 {
 	/*
 	 * We inherit a bunch of functions from execlists that we'd like
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.h b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.h
index 54d716828352..a0132f061ebc 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.h
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.h
@@ -63,5 +63,6 @@ void intel_guc_submission_disable(struct intel_guc *guc);
 void intel_guc_submission_fini(struct intel_guc *guc);
 int intel_guc_preempt_work_create(struct intel_guc *guc);
 void intel_guc_preempt_work_destroy(struct intel_guc *guc);
+void guc_set_default_submission(struct intel_engine_cs *engine);
 
 #endif
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_uc.c b/drivers/gpu/drm/i915/gt/uc/intel_uc.c
index 629b19377a29..4dd43b99a334 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_uc.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_uc.c
@@ -605,6 +605,14 @@ static int __uc_resume(struct intel_uc *uc, bool enable_communication)
 	if (enable_communication)
 		guc_enable_communication(guc);
 
+	/*
+	 * If GuC communication is enabled but submission is not supported,
+	 * we do not need to resume the GuC but we do need to enable the
+	 * GuC communication on resume (above).
+	 */
+	if (!intel_guc_submission_is_enabled(guc))
+		return 0;
+
 	err = intel_guc_resume(guc);
 	if (err) {
 		DRM_DEBUG_DRIVER("Failed to resume GuC, err=%d", err);
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index a22d969cb352..d54a5cba0745 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -78,8 +78,10 @@
 
 #include "gt/intel_lrc.h"
 #include "gt/intel_engine.h"
+#include "gt/intel_gt.h"
 #include "gt/intel_gt_types.h"
 #include "gt/intel_workarounds.h"
+#include "gt/uc/intel_guc_submission.h"
 #include "gt/uc/intel_uc.h"
 
 #include "intel_device_info.h"
@@ -2028,4 +2030,16 @@ i915_coherent_map_type(struct drm_i915_private *i915)
 	return HAS_LLC(i915) ? I915_MAP_WB : I915_MAP_WC;
 }
 
+static inline bool intel_guc_submission_is_enabled(struct intel_guc *guc)
+{
+	struct intel_gt *gt = guc_to_gt(guc);
+	struct intel_engine_cs *engine;
+	enum intel_engine_id id;
+
+	for_each_engine(engine, gt, id)
+		return engine->set_default_submission ==
+			guc_set_default_submission;
+	return false;
+}
+
 #endif
-- 
2.20.1