[Intel-gfx] [RFCv3 12/15] drm/i915: Support context single submission

[Zhi Wang]

This patch introduces the support of context signle submission. As GVT
context may come from different guests, which requires different
configuration of render registers. It can't be combined in a dual ELSP
submission combo.

We make this function as a context feature in context creation service.
Only GVT-g will create this kinds of GEM context currently.

Signed-off-by: Zhi Wang <zhi.a.wang at intel.com>
---
 drivers/gpu/drm/i915/i915_drv.h  |  1 +
 drivers/gpu/drm/i915/intel_lrc.c | 10 +++++++++-
 drivers/gpu/drm/i915/intel_lrc.h |  1 +
 3 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 68b821a..d7fc738 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -895,6 +895,7 @@ struct intel_context {
 		bool need_status_change_notification;
 		struct atomic_notifier_head status_notifier_head;
 	} engine[I915_NUM_RINGS];
+	bool single_submission;
 
 	struct list_head link;
 };
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index ae1ab92..3a047fe 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -472,6 +472,9 @@ static void execlists_context_unqueue(struct intel_engine_cs *ring)
 				 execlist_link) {
 		if (!req0) {
 			req0 = cursor;
+			/* req0 ctx requires single submission, stop picking */
+			if (req0->ctx->single_submission)
+				break;
 		} else if (req0->ctx == cursor->ctx) {
 			/* Same ctx: ignore first request, as second request
 			 * will update tail past first request's workload */
@@ -480,7 +483,12 @@ static void execlists_context_unqueue(struct intel_engine_cs *ring)
 				       &ring->execlist_retired_req_list);
 			req0 = cursor;
 		} else {
-			req1 = cursor;
+			/*
+			 * req0 ctx doesn't require single submission, but
+			 * next req ctx requires, stop picking req1
+			 */
+			if (!cursor->ctx->single_submission)
+				req1 = cursor;
 			break;
 		}
 	}
diff --git a/drivers/gpu/drm/i915/intel_lrc.h b/drivers/gpu/drm/i915/intel_lrc.h
index 15791d4..4873dd8 100644
--- a/drivers/gpu/drm/i915/intel_lrc.h
+++ b/drivers/gpu/drm/i915/intel_lrc.h
@@ -107,6 +107,7 @@ struct intel_lr_context_alloc_params {
 	u32 ringbuffer_size;
 	bool ctx_needs_init;
 	bool ctx_needs_status_change_notification;
+	bool ctx_needs_single_submission;
 };
 
 void intel_lr_context_free(struct intel_context *ctx);
-- 
1.9.1