In the next few patches, we will have a hard requirement that we emit a
context-switch to the perma-pinned i915->kernel_context (so that we can
save the HW state using that context-switch). As the first context
itself may be classed as a kernel context, we want to be explicit in our
comparison. For an extra-layer of finesse, we can check the last
unretired context on the engine; as well as the last retired context
when idle.
v2: verbose verbosity
v3: Always force the switch, even when the engine is idle, and update
the assert that this happens before suspend.
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx> #v1
Reviewed-by: Mika Kuoppala <mika.kuoppala@xxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/i915_gem.c | 10 ++++++----
drivers/gpu/drm/i915/intel_engine_cs.c | 26 ++++++++++++++++++++++++--
2 files changed, 30 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 889ae8810d5f..824515556733 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -4693,14 +4693,16 @@ void __i915_gem_object_release_unless_active(struct drm_i915_gem_object *obj)
i915_gem_object_put(obj);
}
-static void assert_kernel_context_is_current(struct drm_i915_private *dev_priv)
+static void assert_kernel_context_is_current(struct drm_i915_private *i915)
{
+ struct i915_gem_context *kernel_context = i915->kernel_context;
struct intel_engine_cs *engine;
enum intel_engine_id id;
- for_each_engine(engine, dev_priv, id)
- GEM_BUG_ON(engine->last_retired_context &&
- !i915_gem_context_is_kernel(engine->last_retired_context));
+ for_each_engine(engine, i915, id) {
+ GEM_BUG_ON(__i915_gem_active_peek(&engine->timeline->last_request));
+ GEM_BUG_ON(engine->last_retired_context != kernel_context);
+ }
}
void i915_gem_sanitize(struct drm_i915_private *i915)
diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c
index a91355c41d45..047fca656b4d 100644
--- a/drivers/gpu/drm/i915/intel_engine_cs.c
+++ b/drivers/gpu/drm/i915/intel_engine_cs.c
@@ -1593,10 +1593,32 @@ bool intel_engines_are_idle(struct drm_i915_private *dev_priv)
return true;
}
+/**
+ * intel_engine_has_kernel_context:
+ * @engine: the engine
+ *
+ * Returns true if the last context to be executed on this engine, or has been
+ * executed if the engine is already idle, is the kernel context
+ * (#i915.kernel_context).
+ */
bool intel_engine_has_kernel_context(const struct intel_engine_cs *engine)
{
- return (!engine->last_retired_context ||
- i915_gem_context_is_kernel(engine->last_retired_context));
+ const struct i915_gem_context * const kernel_context =
+ engine->i915->kernel_context;
+ struct drm_i915_gem_request *rq;
+
+ lockdep_assert_held(&engine->i915->drm.struct_mutex);
+
+ /*
+ * Check the last context seen by the engine. If active, it will be
+ * the last request that remains in the timeline. When idle, it is
+ * the last executed context as tracked by retirement.
+ */
+ rq = __i915_gem_active_peek(&engine->timeline->last_request);
+ if (rq)
+ return rq->ctx == kernel_context;
+ else
+ return engine->last_retired_context == kernel_context;
}
void intel_engines_reset_default_submission(struct drm_i915_private *i915)
--
2.15.0
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