[PATCH 11/15] drm/i915: Record space required for request emission

[Chris Wilson]

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_gem_request.c |  1 +
 drivers/gpu/drm/i915/intel_lrc.c        |  6 ++++++
 drivers/gpu/drm/i915/intel_ringbuffer.c | 29 +++++++++++++++++++++++++++--
 drivers/gpu/drm/i915/intel_ringbuffer.h |  1 +
 4 files changed, 35 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_request.c b/drivers/gpu/drm/i915/i915_gem_request.c
index d09cfb368a5d..d542fa90a7cf 100644
--- a/drivers/gpu/drm/i915/i915_gem_request.c
+++ b/drivers/gpu/drm/i915/i915_gem_request.c
@@ -424,6 +424,7 @@ i915_gem_request_alloc(struct intel_engine_cs *engine,
 	 * away, e.g. because a GPU scheduler has deferred it.
 	 */
 	req->reserved_space = MIN_SPACE_FOR_ADD_REQUEST;
+	GEM_BUG_ON(req->reserved_space < engine->emit_request_sz);
 
 	if (i915.enable_execlists)
 		ret = intel_logical_ring_alloc_request_extras(req);
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 00fcf36ba919..7e944a0acc10 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -1572,6 +1572,8 @@ static int gen8_emit_request(struct drm_i915_gem_request *request)
 	return intel_logical_ring_advance(request);
 }
 
+static const int gen8_emit_request_sz = 6 + WA_TAIL_DWORDS;
+
 static int gen8_emit_request_render(struct drm_i915_gem_request *request)
 {
 	struct intel_ring *ring = request->ring;
@@ -1603,6 +1605,8 @@ static int gen8_emit_request_render(struct drm_i915_gem_request *request)
 	return intel_logical_ring_advance(request);
 }
 
+static const int gen8_emit_request_render_sz = 8 + WA_TAIL_DWORDS;
+
 static int gen8_init_rcs_context(struct drm_i915_gem_request *req)
 {
 	int ret;
@@ -1677,6 +1681,7 @@ logical_ring_default_vfuncs(struct intel_engine_cs *engine)
 	engine->reset_hw = reset_common_ring;
 	engine->emit_flush = gen8_emit_flush;
 	engine->emit_request = gen8_emit_request;
+	engine->emit_request_sz = gen8_emit_request_sz;
 	engine->submit_request = execlists_submit_request;
 
 	engine->irq_enable = gen8_logical_ring_enable_irq;
@@ -1799,6 +1804,7 @@ int logical_render_ring_init(struct intel_engine_cs *engine)
 	engine->init_context = gen8_init_rcs_context;
 	engine->emit_flush = gen8_emit_flush_render;
 	engine->emit_request = gen8_emit_request_render;
+	engine->emit_request_sz = gen8_emit_request_render_sz;
 
 	ret = intel_engine_create_scratch(engine, 4096);
 	if (ret)
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 597e35c9b699..c8c9ad40fd93 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -1405,6 +1405,8 @@ static int i9xx_emit_request(struct drm_i915_gem_request *req)
 	return 0;
 }
 
+static const int i9xx_emit_request_sz = 4;
+
 /**
  * gen6_sema_emit_request - Update the semaphore mailbox registers
  *
@@ -1458,6 +1460,8 @@ static int gen8_render_emit_request(struct drm_i915_gem_request *req)
 	return 0;
 }
 
+static const int gen8_render_emit_request_sz = 8;
+
 /**
  * intel_ring_sync - sync the waiter to the signaller on seqno
  *
@@ -2677,8 +2681,21 @@ static void intel_ring_default_vfuncs(struct drm_i915_private *dev_priv,
 	engine->reset_hw = reset_ring_common;
 
 	engine->emit_request = i9xx_emit_request;
-	if (i915.semaphores)
+	engine->emit_request_sz = i9xx_emit_request_sz;
+	if (i915.semaphores) {
+		int num_rings;
+
 		engine->emit_request = gen6_sema_emit_request;
+
+		num_rings = hweight32(INTEL_INFO(dev_priv)->ring_mask) - 1;
+		if (INTEL_GEN(dev_priv) >= 8) {
+			engine->emit_request_sz += num_rings * 6;
+		} else {
+			engine->emit_request_sz += num_rings * 3;
+			if (num_rings & 1)
+				engine->emit_request_sz++;
+		}
+	}
 	engine->submit_request = i9xx_submit_request;
 
 	if (INTEL_GEN(dev_priv) >= 8)
@@ -2706,9 +2723,17 @@ int intel_init_render_ring_buffer(struct intel_engine_cs *engine)
 	if (INTEL_GEN(dev_priv) >= 8) {
 		engine->init_context = intel_rcs_ctx_init;
 		engine->emit_request = gen8_render_emit_request;
+		engine->emit_request_sz = gen8_render_emit_request_sz;
 		engine->emit_flush = gen8_render_ring_flush;
-		if (i915.semaphores)
+		if (i915.semaphores) {
+			int num_rings;
+
 			engine->semaphore.signal = gen8_rcs_signal;
+
+			num_rings =
+				hweight32(INTEL_INFO(dev_priv)->ring_mask) - 1;
+			engine->emit_request_sz += num_rings * 6;
+		}
 	} else if (INTEL_GEN(dev_priv) >= 6) {
 		engine->init_context = intel_rcs_ctx_init;
 		engine->emit_flush = gen7_render_ring_flush;
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index dfa64929eae1..fdf2134d1128 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -227,6 +227,7 @@ struct intel_engine_cs {
 #define I915_DISPATCH_PINNED BIT(1)
 #define I915_DISPATCH_RS     BIT(2)
 	int		(*emit_request)(struct drm_i915_gem_request *req);
+	int		emit_request_sz;
 
 	/* Pass the request to the hardware queue (e.g. directly into
 	 * the legacy ringbuffer or to the end of an execlist).
-- 
2.9.3