From f9228f7658734fe16ef7eec554d187a3d9577be8 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Mon, 11 Nov 2019 12:09:57 +0000 Subject: [PATCH] drm/i915/gt: Try an extra flush on the Haswell blitter On gen7, including Haswell, the MI_FLUSH_DW command is not synchronous with the command streamer nor is there an option to make it so. To hide this we add a large delay on the CS so that the breadcrumb should always be visible before the interrupt. However, that does not seem to be enough to ensure the memory is actually coherent with the read of the breadcrumb. The breadcrumb update is a post-sync op... Throw in a preliminary MI_FLUSH_DW before the breadcrumb update in the hope that helps. References: https://bugs.freedesktop.org/show_bug.cgi?id=112147 Testcase: igt/i915_selftest/live_blt Signed-off-by: Chris Wilson Acked-by: Mika Kuoppala Link: https://patchwork.freedesktop.org/patch/msgid/20191111120957.17732-1-chris@chris-wilson.co.uk --- drivers/gpu/drm/i915/gt/intel_ring_submission.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/gt/intel_ring_submission.c b/drivers/gpu/drm/i915/gt/intel_ring_submission.c index a47d5a7c32c96..fc29df7128108 100644 --- a/drivers/gpu/drm/i915/gt/intel_ring_submission.c +++ b/drivers/gpu/drm/i915/gt/intel_ring_submission.c @@ -454,6 +454,10 @@ static u32 *gen7_xcs_emit_breadcrumb(struct i915_request *rq, u32 *cs) GEM_BUG_ON(i915_request_active_timeline(rq)->hwsp_ggtt != rq->engine->status_page.vma); GEM_BUG_ON(offset_in_page(i915_request_active_timeline(rq)->hwsp_offset) != I915_GEM_HWS_SEQNO_ADDR); + *cs++ = MI_FLUSH_DW; + *cs++ = 0; + *cs++ = 0; + *cs++ = MI_FLUSH_DW | MI_FLUSH_DW_OP_STOREDW | MI_FLUSH_DW_STORE_INDEX; *cs++ = I915_GEM_HWS_SEQNO_ADDR | MI_FLUSH_DW_USE_GTT; *cs++ = rq->fence.seqno; @@ -469,7 +473,6 @@ static u32 *gen7_xcs_emit_breadcrumb(struct i915_request *rq, u32 *cs) *cs++ = 0; *cs++ = MI_USER_INTERRUPT; - *cs++ = MI_NOOP; rq->tail = intel_ring_offset(rq, cs); assert_ring_tail_valid(rq->ring, rq->tail); -- 2.39.5