From 826259f5e5260df5349907e60f8ad31b2ec7a485 Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Fri, 6 Mar 2020 07:16:12 +0000
Subject: drm/i915: Assert requests within a context are submitted in order
Git-commit: 1eaa251b66a6dfb53cc647fbd79e3b8512ccf8f3
Patch-mainline: v5.7-rc1
References: jsc#SLE-12680, jsc#SLE-12880, jsc#SLE-12882, jsc#SLE-12883, jsc#SLE-13496, jsc#SLE-15322
Check the flow of requests into the hardware to verify that are
submitted in order along their timeline.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200306071614.2846708-1-chris@chris-wilson.co.uk
Signed-off-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/i915/gt/intel_lrc.c | 4 ++++
drivers/gpu/drm/i915/i915_request.c | 11 +++++++++++
2 files changed, 15 insertions(+)
diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
index 07d137851763..1d63aef8e973 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -1622,6 +1622,7 @@ static bool can_merge_rq(const struct i915_request *prev,
if (!can_merge_ctx(prev->context, next->context))
return false;
+ GEM_BUG_ON(i915_seqno_passed(prev->fence.seqno, next->fence.seqno));
return true;
}
@@ -2141,6 +2142,9 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
GEM_BUG_ON(last &&
!can_merge_ctx(last->context,
rq->context));
+ GEM_BUG_ON(last &&
+ i915_seqno_passed(last->fence.seqno,
+ rq->fence.seqno));
submit = true;
last = rq;
diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index 92a4331df5fd..da88f9082b5a 100644
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -749,6 +749,7 @@ __i915_request_create(struct intel_context *ce, gfp_t gfp)
RCU_INIT_POINTER(rq->timeline, tl);
RCU_INIT_POINTER(rq->hwsp_cacheline, tl->hwsp_cacheline);
rq->hwsp_seqno = tl->hwsp_seqno;
+ GEM_BUG_ON(i915_request_completed(rq));
rq->rcustate = get_state_synchronize_rcu(); /* acts as smp_mb() */
@@ -1296,6 +1297,16 @@ __i915_request_add_to_timeline(struct i915_request *rq)
prev = to_request(__i915_active_fence_set(&timeline->last_request,
&rq->fence));
if (prev && !i915_request_completed(prev)) {
+ /*
+ * The requests are supposed to be kept in order. However,
+ * we need to be wary in case the timeline->last_request
+ * is used as a barrier for external modification to this
+ * context.
+ */
+ GEM_BUG_ON(prev->context == rq->context &&
+ i915_seqno_passed(prev->fence.seqno,
+ rq->fence.seqno));
+
if (is_power_of_2(prev->engine->mask | rq->engine->mask))
i915_sw_fence_await_sw_fence(&rq->submit,
&prev->submit,
--
2.28.0