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-rw-r--r--drivers/gpu/drm/i915/i915_request.c26
-rw-r--r--drivers/gpu/drm/i915/i915_scheduler_types.h1
2 files changed, 27 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index 9df2cb8d66d0..2c0de3a3b8e8 100644
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -1003,6 +1003,15 @@ emit_semaphore_wait(struct i915_request *to,
if (!rcu_access_pointer(from->hwsp_cacheline))
goto await_fence;
+ /*
+ * If this or its dependents are waiting on an external fence
+ * that may fail catastrophically, then we want to avoid using
+ * sempahores as they bypass the fence signaling metadata, and we
+ * lose the fence->error propagation.
+ */
+ if (from->sched.flags & I915_SCHED_HAS_EXTERNAL_CHAIN)
+ goto await_fence;
+
/* Just emit the first semaphore we see as request space is limited. */
if (already_busywaiting(to) & mask)
goto await_fence;
@@ -1065,12 +1074,29 @@ i915_request_await_request(struct i915_request *to, struct i915_request *from)
return ret;
}
+ if (from->sched.flags & I915_SCHED_HAS_EXTERNAL_CHAIN)
+ to->sched.flags |= I915_SCHED_HAS_EXTERNAL_CHAIN;
+
return 0;
}
+static void mark_external(struct i915_request *rq)
+{
+ /*
+ * The downside of using semaphores is that we lose metadata passing
+ * along the signaling chain. This is particularly nasty when we
+ * need to pass along a fatal error such as EFAULT or EDEADLK. For
+ * fatal errors we want to scrub the request before it is executed,
+ * which means that we cannot preload the request onto HW and have
+ * it wait upon a semaphore.
+ */
+ rq->sched.flags |= I915_SCHED_HAS_EXTERNAL_CHAIN;
+}
+
static int
__i915_request_await_external(struct i915_request *rq, struct dma_fence *fence)
{
+ mark_external(rq);
return i915_sw_fence_await_dma_fence(&rq->submit, fence,
fence->context ? I915_FENCE_TIMEOUT : 0,
I915_FENCE_GFP);
diff --git a/drivers/gpu/drm/i915/i915_scheduler_types.h b/drivers/gpu/drm/i915/i915_scheduler_types.h
index 7186875088a0..6ab2c5289bed 100644
--- a/drivers/gpu/drm/i915/i915_scheduler_types.h
+++ b/drivers/gpu/drm/i915/i915_scheduler_types.h
@@ -66,6 +66,7 @@ struct i915_sched_node {
struct i915_sched_attr attr;
unsigned int flags;
#define I915_SCHED_HAS_SEMAPHORE_CHAIN BIT(0)
+#define I915_SCHED_HAS_EXTERNAL_CHAIN BIT(1)
intel_engine_mask_t semaphores;
};