[Intel-gfx] [PATCH] drm/i915/ringbuffer: Drop gen7_xcs_emit_breadcrumb

[Chris Wilson]

The additional flushes for gen7 appear to have been a red herring as the
more efficacious workaround seems to be commit 476af9c26063 ("drm/i915/gen6:
Flush RING_IMR changes before changing the global GT IMR"). Trusting the
updated results means we can remove the special casing for gen7_xcs and
reduce it to the gen6_xcs_emit_breadcrumb.

References: 476af9c26063 ("drm/i915/gen6: Flush RING_IMR changes before changing the global GT IMR")
Fixes: 1212bd821de8 ("drm/i915/ringbuffer: Move irq seqno barrier to the GPU for gen7")
Testcase: igt/gem_sync
Testcase: igt/gem_exec_whisper
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/intel_ringbuffer.c | 54 ++++---------------------
 1 file changed, 8 insertions(+), 46 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 3d5d6b908148..2ac0c3a0d473 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -433,8 +433,8 @@ static const int gen7_rcs_emit_breadcrumb_sz = 6;
 
 static void gen6_xcs_emit_breadcrumb(struct i915_request *rq, u32 *cs)
 {
-	*cs++ = MI_FLUSH_DW | MI_FLUSH_DW_OP_STOREDW;
-	*cs++ = intel_hws_seqno_address(rq->engine) | MI_FLUSH_DW_USE_GTT;
+	*cs++ = MI_FLUSH_DW | MI_FLUSH_DW_OP_STOREDW | MI_FLUSH_DW_STORE_INDEX;
+	*cs++ = I915_GEM_HWS_INDEX_ADDR | MI_FLUSH_DW_USE_GTT;
 	*cs++ = rq->global_seqno;
 	*cs++ = MI_USER_INTERRUPT;
 
@@ -443,34 +443,6 @@ static void gen6_xcs_emit_breadcrumb(struct i915_request *rq, u32 *cs)
 }
 static const int gen6_xcs_emit_breadcrumb_sz = 4;
 
-#define GEN7_XCS_WA 32
-static void gen7_xcs_emit_breadcrumb(struct i915_request *rq, u32 *cs)
-{
-	int i;
-
-	*cs++ = MI_FLUSH_DW | MI_FLUSH_DW_OP_STOREDW;
-	*cs++ = intel_hws_seqno_address(rq->engine) | MI_FLUSH_DW_USE_GTT;
-	*cs++ = rq->global_seqno;
-
-	for (i = 0; i < GEN7_XCS_WA; i++) {
-		*cs++ = MI_STORE_DWORD_INDEX;
-		*cs++ = I915_GEM_HWS_INDEX_ADDR;
-		*cs++ = rq->global_seqno;
-	}
-
-	*cs++ = MI_FLUSH_DW;
-	*cs++ = 0;
-	*cs++ = 0;
-
-	*cs++ = MI_USER_INTERRUPT;
-	*cs++ = MI_NOOP;
-
-	rq->tail = intel_ring_offset(rq, cs);
-	assert_ring_tail_valid(rq->ring, rq->tail);
-}
-static const int gen7_xcs_emit_breadcrumb_sz = 8 + GEN7_XCS_WA * 3;
-#undef GEN7_XCS_WA
-
 static void set_hwstam(struct intel_engine_cs *engine, u32 mask)
 {
 	/*
@@ -2267,13 +2239,8 @@ int intel_init_bsd_ring_buffer(struct intel_engine_cs *engine)
 		engine->emit_flush = gen6_bsd_ring_flush;
 		engine->irq_enable_mask = GT_BSD_USER_INTERRUPT;
 
-		if (IS_GEN(dev_priv, 6)) {
-			engine->emit_breadcrumb = gen6_xcs_emit_breadcrumb;
-			engine->emit_breadcrumb_sz = gen6_xcs_emit_breadcrumb_sz;
-		} else {
-			engine->emit_breadcrumb = gen7_xcs_emit_breadcrumb;
-			engine->emit_breadcrumb_sz = gen7_xcs_emit_breadcrumb_sz;
-		}
+		engine->emit_breadcrumb = gen6_xcs_emit_breadcrumb;
+		engine->emit_breadcrumb_sz = gen6_xcs_emit_breadcrumb_sz;
 	} else {
 		engine->emit_flush = bsd_ring_flush;
 		if (IS_GEN(dev_priv, 5))
@@ -2296,13 +2263,8 @@ int intel_init_blt_ring_buffer(struct intel_engine_cs *engine)
 	engine->emit_flush = gen6_ring_flush;
 	engine->irq_enable_mask = GT_BLT_USER_INTERRUPT;
 
-	if (IS_GEN(dev_priv, 6)) {
-		engine->emit_breadcrumb = gen6_xcs_emit_breadcrumb;
-		engine->emit_breadcrumb_sz = gen6_xcs_emit_breadcrumb_sz;
-	} else {
-		engine->emit_breadcrumb = gen7_xcs_emit_breadcrumb;
-		engine->emit_breadcrumb_sz = gen7_xcs_emit_breadcrumb_sz;
-	}
+	engine->emit_breadcrumb = gen6_xcs_emit_breadcrumb;
+	engine->emit_breadcrumb_sz = gen6_xcs_emit_breadcrumb_sz;
 
 	return intel_init_ring_buffer(engine);
 }
@@ -2320,8 +2282,8 @@ int intel_init_vebox_ring_buffer(struct intel_engine_cs *engine)
 	engine->irq_enable = hsw_vebox_irq_enable;
 	engine->irq_disable = hsw_vebox_irq_disable;
 
-	engine->emit_breadcrumb = gen7_xcs_emit_breadcrumb;
-	engine->emit_breadcrumb_sz = gen7_xcs_emit_breadcrumb_sz;
+	engine->emit_breadcrumb = gen6_xcs_emit_breadcrumb;
+	engine->emit_breadcrumb_sz = gen6_xcs_emit_breadcrumb_sz;
 
 	return intel_init_ring_buffer(engine);
 }
-- 
2.20.1