[PATCH 06/60] drm/i915/ringbuffer: Remove irq-seqno w/a for gen6/7 rcs

Chris Wilson chris at chris-wilson.co.uk
Sat Dec 22 03:06:38 UTC 2018


Having transitioned to using PIPECONTROL to combine the flush with the
breadcrumb write using their post-sync functions, assume that this will
resolve the serialisation with the subsequent MI_USER_INTERRUPT. That is
when inspecting the breadcrumb after an interrupt we can rely on the write
being posted (i.e. the HWSP will be coherent).

Testing using gem_sync shows that the PIPECONTROL + CS stall does
serialise the command streamer sufficient that the breadcrumb lands
before the MI_USER_INTERRUPT. The same is not true for MI_FLUSH_DW.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/intel_ringbuffer.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 3e468c6eb86a..54f4cfd51bc5 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -2178,13 +2178,11 @@ int intel_init_render_ring_buffer(struct intel_engine_cs *engine)
 		engine->emit_flush = gen7_render_ring_flush;
 		engine->emit_breadcrumb = gen7_rcs_emit_breadcrumb;
 		engine->emit_breadcrumb_sz = gen7_rcs_emit_breadcrumb_sz;
-		engine->irq_seqno_barrier = gen6_seqno_barrier;
 	} else if (IS_GEN(dev_priv, 6)) {
 		engine->init_context = intel_rcs_ctx_init;
 		engine->emit_flush = gen6_render_ring_flush;
 		engine->emit_breadcrumb = gen6_rcs_emit_breadcrumb;
 		engine->emit_breadcrumb_sz = gen6_rcs_emit_breadcrumb_sz;
-		engine->irq_seqno_barrier = gen6_seqno_barrier;
 	} else if (IS_GEN(dev_priv, 5)) {
 		engine->emit_flush = gen4_render_ring_flush;
 	} else {
-- 
2.20.1



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