drm/i915: Invert the GEM wakeref hierarchy

In the current scheme, on submitting a request we take a single global
GEM wakeref, which trickles down to wake up all GT power domains. This
is undesirable as we would like to be able to localise our power
management to the available power domains and to remove the global GEM
operations from the heart of the driver. (The intent there is to push
global GEM decisions to the boundary as used by the GEM user interface.)

Now during request construction, each request is responsible via its
logical context to acquire a wakeref on each power domain it intends to
utilize. Currently, each request takes a wakeref on the engine(s) and
the engines themselves take a chipset wakeref. This gives us a
transition on each engine which we can extend if we want to insert more
powermangement control (such as soft rc6). The global GEM operations
that currently require a struct_mutex are reduced to listening to pm
events from the chipset GT wakeref. As we reduce the struct_mutex
requirement, these listeners should evaporate.

Perhaps the biggest immediate change is that this removes the
struct_mutex requirement around GT power management, allowing us greater
flexibility in request construction. Another important knock-on effect,
is that by tracking engine usage, we can insert a switch back to the
kernel context on that engine immediately, avoiding any extra delay or
inserting global synchronisation barriers. This makes tracking when an
engine and its associated contexts are idle much easier -- important for
when we forgo our assumed execution ordering and need idle barriers to
unpin used contexts. In the process, it means we remove a large chunk of
code whose only purpose was to switch back to the kernel context.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190424200717.1686-5-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/Makefile

@@ -71,6 +71,8 @@ gt-y += \
 	gt/intel_breadcrumbs.o \
 	gt/intel_context.o \
 	gt/intel_engine_cs.o \
+	gt/intel_engine_pm.o \
+	gt/intel_gt_pm.o \
 	gt/intel_hangcheck.o \
 	gt/intel_lrc.o \
 	gt/intel_reset.o \

drivers/gpu/drm/i915/gt/intel_context.c

@@ -10,6 +10,7 @@
 
 #include "intel_context.h"
 #include "intel_engine.h"
+#include "intel_engine_pm.h"
 
 static struct i915_global_context {
 	struct i915_global base;
@@ -162,7 +163,11 @@ intel_context_pin(struct i915_gem_context *ctx,
 		return ERR_PTR(-EINTR);
 
 	if (likely(!atomic_read(&ce->pin_count))) {
-		err = ce->ops->pin(ce);
+		intel_wakeref_t wakeref;
+
+		err = 0;
+		with_intel_runtime_pm(ce->engine->i915, wakeref)
+			err = ce->ops->pin(ce);
 		if (err)
 			goto err;
 
@@ -269,17 +274,10 @@ int __init i915_global_context_init(void)
 
 void intel_context_enter_engine(struct intel_context *ce)
 {
-	struct drm_i915_private *i915 = ce->gem_context->i915;
-
-	if (!i915->gt.active_requests++)
-		i915_gem_unpark(i915);
+	intel_engine_pm_get(ce->engine);
 }
 
 void intel_context_exit_engine(struct intel_context *ce)
 {
-	struct drm_i915_private *i915 = ce->gem_context->i915;
-
-	GEM_BUG_ON(!i915->gt.active_requests);
-	if (!--i915->gt.active_requests)
-		i915_gem_park(i915);
+	intel_engine_pm_put(ce->engine);
 }

drivers/gpu/drm/i915/gt/intel_engine.h

@@ -382,6 +382,8 @@ u64 intel_engine_get_last_batch_head(const struct intel_engine_cs *engine);
 void intel_engine_get_instdone(struct intel_engine_cs *engine,
 			       struct intel_instdone *instdone);
 
+void intel_engine_init_execlists(struct intel_engine_cs *engine);
+
 void intel_engine_init_breadcrumbs(struct intel_engine_cs *engine);
 void intel_engine_fini_breadcrumbs(struct intel_engine_cs *engine);
 
@@ -458,19 +460,14 @@ static inline void intel_engine_reset(struct intel_engine_cs *engine,
 {
 	if (engine->reset.reset)
 		engine->reset.reset(engine, stalled);
+	engine->serial++; /* contexts lost */
 }
 
-void intel_engines_sanitize(struct drm_i915_private *i915, bool force);
-void intel_gt_resume(struct drm_i915_private *i915);
-
 bool intel_engine_is_idle(struct intel_engine_cs *engine);
 bool intel_engines_are_idle(struct drm_i915_private *dev_priv);
 
 void intel_engine_lost_context(struct intel_engine_cs *engine);
 
-void intel_engines_park(struct drm_i915_private *i915);
-void intel_engines_unpark(struct drm_i915_private *i915);
-
 void intel_engines_reset_default_submission(struct drm_i915_private *i915);
 unsigned int intel_engines_has_context_isolation(struct drm_i915_private *i915);
 

drivers/gpu/drm/i915/gt/intel_engine_cs.c

@@ -27,6 +27,7 @@
 #include "i915_drv.h"
 
 #include "intel_engine.h"
+#include "intel_engine_pm.h"
 #include "intel_lrc.h"
 #include "intel_reset.h"
 
@@ -451,7 +452,7 @@ static void intel_engine_init_batch_pool(struct intel_engine_cs *engine)
 	i915_gem_batch_pool_init(&engine->batch_pool, engine);
 }
 
-static void intel_engine_init_execlist(struct intel_engine_cs *engine)
+void intel_engine_init_execlists(struct intel_engine_cs *engine)
 {
 	struct intel_engine_execlists * const execlists = &engine->execlists;
 
@@ -584,10 +585,11 @@ int intel_engine_setup_common(struct intel_engine_cs *engine)
 	i915_timeline_set_subclass(&engine->timeline, TIMELINE_ENGINE);
 
 	intel_engine_init_breadcrumbs(engine);
-	intel_engine_init_execlist(engine);
+	intel_engine_init_execlists(engine);
 	intel_engine_init_hangcheck(engine);
 	intel_engine_init_batch_pool(engine);
 	intel_engine_init_cmd_parser(engine);
+	intel_engine_init__pm(engine);
 
 	/* Use the whole device by default */
 	engine->sseu =
@@ -758,30 +760,6 @@ int intel_engine_init_common(struct intel_engine_cs *engine)
 	return ret;
 }
 
-void intel_gt_resume(struct drm_i915_private *i915)
-{
-	struct intel_engine_cs *engine;
-	enum intel_engine_id id;
-
-	/*
-	 * After resume, we may need to poke into the pinned kernel
-	 * contexts to paper over any damage caused by the sudden suspend.
-	 * Only the kernel contexts should remain pinned over suspend,
-	 * allowing us to fixup the user contexts on their first pin.
-	 */
-	for_each_engine(engine, i915, id) {
-		struct intel_context *ce;
-
-		ce = engine->kernel_context;
-		if (ce)
-			ce->ops->reset(ce);
-
-		ce = engine->preempt_context;
-		if (ce)
-			ce->ops->reset(ce);
-	}
-}
-
 /**
  * intel_engines_cleanup_common - cleans up the engine state created by
  *                                the common initiailizers.
@@ -1128,117 +1106,6 @@ void intel_engines_reset_default_submission(struct drm_i915_private *i915)
 		engine->set_default_submission(engine);
 }
 
-static bool reset_engines(struct drm_i915_private *i915)
-{
-	if (INTEL_INFO(i915)->gpu_reset_clobbers_display)
-		return false;
-
-	return intel_gpu_reset(i915, ALL_ENGINES) == 0;
-}
-
-/**
- * intel_engines_sanitize: called after the GPU has lost power
- * @i915: the i915 device
- * @force: ignore a failed reset and sanitize engine state anyway
- *
- * Anytime we reset the GPU, either with an explicit GPU reset or through a
- * PCI power cycle, the GPU loses state and we must reset our state tracking
- * to match. Note that calling intel_engines_sanitize() if the GPU has not
- * been reset results in much confusion!
- */
-void intel_engines_sanitize(struct drm_i915_private *i915, bool force)
-{
-	struct intel_engine_cs *engine;
-	enum intel_engine_id id;
-
-	GEM_TRACE("\n");
-
-	if (!reset_engines(i915) && !force)
-		return;
-
-	for_each_engine(engine, i915, id)
-		intel_engine_reset(engine, false);
-}
-
-/**
- * intel_engines_park: called when the GT is transitioning from busy->idle
- * @i915: the i915 device
- *
- * The GT is now idle and about to go to sleep (maybe never to wake again?).
- * Time for us to tidy and put away our toys (release resources back to the
- * system).
- */
-void intel_engines_park(struct drm_i915_private *i915)
-{
-	struct intel_engine_cs *engine;
-	enum intel_engine_id id;
-
-	for_each_engine(engine, i915, id) {
-		/* Flush the residual irq tasklets first. */
-		intel_engine_disarm_breadcrumbs(engine);
-		tasklet_kill(&engine->execlists.tasklet);
-
-		/*
-		 * We are committed now to parking the engines, make sure there
-		 * will be no more interrupts arriving later and the engines
-		 * are truly idle.
-		 */
-		if (wait_for(intel_engine_is_idle(engine), 10)) {
-			struct drm_printer p = drm_debug_printer(__func__);
-
-			dev_err(i915->drm.dev,
-				"%s is not idle before parking\n",
-				engine->name);
-			intel_engine_dump(engine, &p, NULL);
-		}
-
-		/* Must be reset upon idling, or we may miss the busy wakeup. */
-		GEM_BUG_ON(engine->execlists.queue_priority_hint != INT_MIN);
-
-		if (engine->park)
-			engine->park(engine);
-
-		if (engine->pinned_default_state) {
-			i915_gem_object_unpin_map(engine->default_state);
-			engine->pinned_default_state = NULL;
-		}
-
-		i915_gem_batch_pool_fini(&engine->batch_pool);
-		engine->execlists.no_priolist = false;
-	}
-
-	i915->gt.active_engines = 0;
-}
-
-/**
- * intel_engines_unpark: called when the GT is transitioning from idle->busy
- * @i915: the i915 device
- *
- * The GT was idle and now about to fire up with some new user requests.
- */
-void intel_engines_unpark(struct drm_i915_private *i915)
-{
-	struct intel_engine_cs *engine;
-	enum intel_engine_id id;
-
-	for_each_engine(engine, i915, id) {
-		void *map;
-
-		/* Pin the default state for fast resets from atomic context. */
-		map = NULL;
-		if (engine->default_state)
-			map = i915_gem_object_pin_map(engine->default_state,
-						      I915_MAP_WB);
-		if (!IS_ERR_OR_NULL(map))
-			engine->pinned_default_state = map;
-
-		if (engine->unpark)
-			engine->unpark(engine);
-
-		intel_engine_init_hangcheck(engine);
-	}
-}
-
 /**
  * intel_engine_lost_context: called when the GPU is reset into unknown state
  * @engine: the engine
@@ -1523,6 +1390,7 @@ void intel_engine_dump(struct intel_engine_cs *engine,
 	if (i915_reset_failed(engine->i915))
 		drm_printf(m, "*** WEDGED ***\n");
 
+	drm_printf(m, "\tAwake? %d\n", atomic_read(&engine->wakeref.count));
 	drm_printf(m, "\tHangcheck %x:%x [%d ms]\n",
 		   engine->hangcheck.last_seqno,
 		   engine->hangcheck.next_seqno,

drivers/gpu/drm/i915/gt/intel_engine_pm.c

+/*
+ * SPDX-License-Identifier: MIT
+ *
+ * Copyright © 2019 Intel Corporation
+ */
+
+#include "i915_drv.h"
+
+#include "intel_engine.h"
+#include "intel_engine_pm.h"
+#include "intel_gt_pm.h"
+
+static int intel_engine_unpark(struct intel_wakeref *wf)
+{
+	struct intel_engine_cs *engine =
+		container_of(wf, typeof(*engine), wakeref);
+	void *map;
+
+	GEM_TRACE("%s\n", engine->name);
+
+	intel_gt_pm_get(engine->i915);
+
+	/* Pin the default state for fast resets from atomic context. */
+	map = NULL;
+	if (engine->default_state)
+		map = i915_gem_object_pin_map(engine->default_state,
+					      I915_MAP_WB);
+	if (!IS_ERR_OR_NULL(map))
+		engine->pinned_default_state = map;
+
+	if (engine->unpark)
+		engine->unpark(engine);
+
+	intel_engine_init_hangcheck(engine);
+	return 0;
+}
+
+void intel_engine_pm_get(struct intel_engine_cs *engine)
+{
+	intel_wakeref_get(engine->i915, &engine->wakeref, intel_engine_unpark);
+}
+
+static bool switch_to_kernel_context(struct intel_engine_cs *engine)
+{
+	struct i915_request *rq;
+
+	/* Already inside the kernel context, safe to power down. */
+	if (engine->wakeref_serial == engine->serial)
+		return true;
+
+	/* GPU is pointing to the void, as good as in the kernel context. */
+	if (i915_reset_failed(engine->i915))
+		return true;
+
+	/*
+	 * Note, we do this without taking the timeline->mutex. We cannot
+	 * as we may be called while retiring the kernel context and so
+	 * already underneath the timeline->mutex. Instead we rely on the
+	 * exclusive property of the intel_engine_park that prevents anyone
+	 * else from creating a request on this engine. This also requires
+	 * that the ring is empty and we avoid any waits while constructing
+	 * the context, as they assume protection by the timeline->mutex.
+	 * This should hold true as we can only park the engine after
+	 * retiring the last request, thus all rings should be empty and
+	 * all timelines idle.
+	 */
+	rq = __i915_request_create(engine->kernel_context, GFP_NOWAIT);
+	if (IS_ERR(rq))
+		/* Context switch failed, hope for the best! Maybe reset? */
+		return true;
+
+	/* Check again on the next retirement. */
+	engine->wakeref_serial = engine->serial + 1;
+	__i915_request_commit(rq);
+
+	return false;
+}
+
+static int intel_engine_park(struct intel_wakeref *wf)
+{
+	struct intel_engine_cs *engine =
+		container_of(wf, typeof(*engine), wakeref);
+
+	/*
+	 * If one and only one request is completed between pm events,
+	 * we know that we are inside the kernel context and it is
+	 * safe to power down. (We are paranoid in case that runtime
+	 * suspend causes corruption to the active context image, and
+	 * want to avoid that impacting userspace.)
+	 */
+	if (!switch_to_kernel_context(engine))
+		return -EBUSY;
+
+	GEM_TRACE("%s\n", engine->name);
+
+	intel_engine_disarm_breadcrumbs(engine);
+
+	/* Must be reset upon idling, or we may miss the busy wakeup. */
+	GEM_BUG_ON(engine->execlists.queue_priority_hint != INT_MIN);
+
+	if (engine->park)
+		engine->park(engine);
+
+	if (engine->pinned_default_state) {
+		i915_gem_object_unpin_map(engine->default_state);
+		engine->pinned_default_state = NULL;
+	}
+
+	engine->execlists.no_priolist = false;
+
+	intel_gt_pm_put(engine->i915);
+	return 0;
+}
+
+void intel_engine_pm_put(struct intel_engine_cs *engine)
+{
+	intel_wakeref_put(engine->i915, &engine->wakeref, intel_engine_park);
+}
+
+void intel_engine_init__pm(struct intel_engine_cs *engine)
+{
+	intel_wakeref_init(&engine->wakeref);
+}
+
+int intel_engines_resume(struct drm_i915_private *i915)
+{
+	struct intel_engine_cs *engine;
+	enum intel_engine_id id;
+	int err = 0;
+
+	intel_gt_pm_get(i915);
+	for_each_engine(engine, i915, id) {
+		intel_engine_pm_get(engine);
+		engine->serial++; /* kernel context lost */
+		err = engine->resume(engine);
+		intel_engine_pm_put(engine);
+		if (err) {
+			dev_err(i915->drm.dev,
+				"Failed to restart %s (%d)\n",
+				engine->name, err);
+			break;
+		}
+	}
+	intel_gt_pm_put(i915);
+
+	return err;
+}

drivers/gpu/drm/i915/gt/intel_engine_pm.h

+/*
+ * SPDX-License-Identifier: MIT
+ *
+ * Copyright © 2019 Intel Corporation
+ */
+
+#ifndef INTEL_ENGINE_PM_H
+#define INTEL_ENGINE_PM_H
+
+struct drm_i915_private;
+struct intel_engine_cs;
+
+void intel_engine_pm_get(struct intel_engine_cs *engine);
+void intel_engine_pm_put(struct intel_engine_cs *engine);
+
+void intel_engine_init__pm(struct intel_engine_cs *engine);
+
+int intel_engines_resume(struct drm_i915_private *i915);
+
+#endif /* INTEL_ENGINE_PM_H */

drivers/gpu/drm/i915/gt/intel_engine_types.h

@@ -20,6 +20,7 @@
 #include "i915_selftest.h"
 #include "i915_timeline_types.h"
 #include "intel_sseu.h"
+#include "intel_wakeref.h"
 #include "intel_workarounds_types.h"
 
 #define I915_MAX_SLICES	3
@@ -287,6 +288,10 @@ struct intel_engine_cs {
 	struct intel_context *kernel_context; /* pinned */
 	struct intel_context *preempt_context; /* pinned; optional */
 
+	unsigned long serial;
+
+	unsigned long wakeref_serial;
+	struct intel_wakeref wakeref;
 	struct drm_i915_gem_object *default_state;
 	void *pinned_default_state;
 
@@ -359,7 +364,7 @@ struct intel_engine_cs {
 	void		(*irq_enable)(struct intel_engine_cs *engine);
 	void		(*irq_disable)(struct intel_engine_cs *engine);
 
-	int		(*init_hw)(struct intel_engine_cs *engine);
+	int		(*resume)(struct intel_engine_cs *engine);
 
 	struct {
 		void (*prepare)(struct intel_engine_cs *engine);

drivers/gpu/drm/i915/gt/intel_gt_pm.c

+/*
+ * SPDX-License-Identifier: MIT
+ *
+ * Copyright © 2019 Intel Corporation
+ */
+
+#include "i915_drv.h"
+#include "intel_gt_pm.h"
+#include "intel_pm.h"
+#include "intel_wakeref.h"
+
+static void pm_notify(struct drm_i915_private *i915, int state)
+{
+	blocking_notifier_call_chain(&i915->gt.pm_notifications, state, i915);
+}
+
+static int intel_gt_unpark(struct intel_wakeref *wf)
+{
+	struct drm_i915_private *i915 =
+		container_of(wf, typeof(*i915), gt.wakeref);
+
+	GEM_TRACE("\n");
+
+	/*
+	 * It seems that the DMC likes to transition between the DC states a lot
+	 * when there are no connected displays (no active power domains) during
+	 * command submission.
+	 *
+	 * This activity has negative impact on the performance of the chip with
+	 * huge latencies observed in the interrupt handler and elsewhere.
+	 *
+	 * Work around it by grabbing a GT IRQ power domain whilst there is any
+	 * GT activity, preventing any DC state transitions.
+	 */
+	i915->gt.awake = intel_display_power_get(i915, POWER_DOMAIN_GT_IRQ);
+	GEM_BUG_ON(!i915->gt.awake);
+
+	intel_enable_gt_powersave(i915);
+
+	i915_update_gfx_val(i915);
+	if (INTEL_GEN(i915) >= 6)
+		gen6_rps_busy(i915);
+
+	i915_pmu_gt_unparked(i915);
+
+	i915_queue_hangcheck(i915);
+
+	pm_notify(i915, INTEL_GT_UNPARK);
+
+	return 0;
+}
+
+void intel_gt_pm_get(struct drm_i915_private *i915)
+{
+	intel_wakeref_get(i915, &i915->gt.wakeref, intel_gt_unpark);
+}
+
+static int intel_gt_park(struct intel_wakeref *wf)
+{
+	struct drm_i915_private *i915 =
+		container_of(wf, typeof(*i915), gt.wakeref);
+	intel_wakeref_t wakeref = fetch_and_zero(&i915->gt.awake);
+
+	GEM_TRACE("\n");
+
+	pm_notify(i915, INTEL_GT_PARK);
+
+	i915_pmu_gt_parked(i915);
+	if (INTEL_GEN(i915) >= 6)
+		gen6_rps_idle(i915);
+
+	GEM_BUG_ON(!wakeref);
+	intel_display_power_put(i915, POWER_DOMAIN_GT_IRQ, wakeref);
+
+	return 0;
+}
+
+void intel_gt_pm_put(struct drm_i915_private *i915)
+{
+	intel_wakeref_put(i915, &i915->gt.wakeref, intel_gt_park);
+}
+
+void intel_gt_pm_init(struct drm_i915_private *i915)
+{
+	intel_wakeref_init(&i915->gt.wakeref);
+	BLOCKING_INIT_NOTIFIER_HEAD(&i915->gt.pm_notifications);
+}
+
+static bool reset_engines(struct drm_i915_private *i915)
+{
+	if (INTEL_INFO(i915)->gpu_reset_clobbers_display)
+		return false;
+
+	return intel_gpu_reset(i915, ALL_ENGINES) == 0;
+}
+
+/**
+ * intel_gt_sanitize: called after the GPU has lost power
+ * @i915: the i915 device
+ * @force: ignore a failed reset and sanitize engine state anyway
+ *
+ * Anytime we reset the GPU, either with an explicit GPU reset or through a
+ * PCI power cycle, the GPU loses state and we must reset our state tracking
+ * to match. Note that calling intel_gt_sanitize() if the GPU has not
+ * been reset results in much confusion!
+ */
+void intel_gt_sanitize(struct drm_i915_private *i915, bool force)
+{
+	struct intel_engine_cs *engine;
+	enum intel_engine_id id;
+
+	GEM_TRACE("\n");
+
+	if (!reset_engines(i915) && !force)
+		return;
+
+	for_each_engine(engine, i915, id)
+		intel_engine_reset(engine, false);
+}
+
+void intel_gt_resume(struct drm_i915_private *i915)
+{
+	struct intel_engine_cs *engine;
+	enum intel_engine_id id;
+
+	/*
+	 * After resume, we may need to poke into the pinned kernel
+	 * contexts to paper over any damage caused by the sudden suspend.
+	 * Only the kernel contexts should remain pinned over suspend,
+	 * allowing us to fixup the user contexts on their first pin.
+	 */
+	for_each_engine(engine, i915, id) {
+		struct intel_context *ce;
+
+		ce = engine->kernel_context;
+		if (ce)
+			ce->ops->reset(ce);
+
+		ce = engine->preempt_context;
+		if (ce)
+			ce->ops->reset(ce);
+	}
+}

drivers/gpu/drm/i915/gt/intel_gt_pm.h

+/*
+ * SPDX-License-Identifier: MIT
+ *
+ * Copyright © 2019 Intel Corporation
+ */
+
+#ifndef INTEL_GT_PM_H
+#define INTEL_GT_PM_H
+
+#include <linux/types.h>
+
+struct drm_i915_private;
+
+enum {
+	INTEL_GT_UNPARK,
+	INTEL_GT_PARK,
+};
+
+void intel_gt_pm_get(struct drm_i915_private *i915);
+void intel_gt_pm_put(struct drm_i915_private *i915);
+
+void intel_gt_pm_init(struct drm_i915_private *i915);
+
+void intel_gt_sanitize(struct drm_i915_private *i915, bool force);
+void intel_gt_resume(struct drm_i915_private *i915);
+
+#endif /* INTEL_GT_PM_H */

drivers/gpu/drm/i915/gt/intel_hangcheck.c

@@ -256,6 +256,7 @@ static void i915_hangcheck_elapsed(struct work_struct *work)
 	struct intel_engine_cs *engine;
 	enum intel_engine_id id;
 	unsigned int hung = 0, stuck = 0, wedged = 0;
+	intel_wakeref_t wakeref;
 
 	if (!i915_modparams.enable_hangcheck)
 		return;
@@ -266,6 +267,10 @@ static void i915_hangcheck_elapsed(struct work_struct *work)
 	if (i915_terminally_wedged(dev_priv))
 		return;
 
+	wakeref = intel_runtime_pm_get_if_in_use(dev_priv);
+	if (!wakeref)
+		return;
+
 	/* As enabling the GPU requires fairly extensive mmio access,
 	 * periodically arm the mmio checker to see if we are triggering
 	 * any invalid access.
@@ -313,6 +318,8 @@ static void i915_hangcheck_elapsed(struct work_struct *work)
 	if (hung)
 		hangcheck_declare_hang(dev_priv, hung, stuck);
 
+	intel_runtime_pm_put(dev_priv, wakeref);
+
 	/* Reset timer in case GPU hangs without another request being added */
 	i915_queue_hangcheck(dev_priv);
 }

drivers/gpu/drm/i915/gt/intel_lrc.c

@@ -1789,7 +1789,7 @@ static bool unexpected_starting_state(struct intel_engine_cs *engine)
 	return unexpected;
 }
 
-static int gen8_init_common_ring(struct intel_engine_cs *engine)
+static int execlists_resume(struct intel_engine_cs *engine)
 {
 	intel_engine_apply_workarounds(engine);
 	intel_engine_apply_whitelist(engine);
@@ -1822,7 +1822,7 @@ static void execlists_reset_prepare(struct intel_engine_cs *engine)
 	 * completed the reset in i915_gem_reset_finish(). If a request
 	 * is completed by one engine, it may then queue a request
 	 * to a second via its execlists->tasklet *just* as we are
-	 * calling engine->init_hw() and also writing the ELSP.
+	 * calling engine->resume() and also writing the ELSP.
 	 * Turning off the execlists->tasklet until the reset is over
 	 * prevents the race.
 	 */
@@ -2391,7 +2391,7 @@ static void
 logical_ring_default_vfuncs(struct intel_engine_cs *engine)
 {
 	/* Default vfuncs which can be overriden by each engine. */
-	engine->init_hw = gen8_init_common_ring;
+	engine->resume = execlists_resume;
 
 	engine->reset.prepare = execlists_reset_prepare;
 	engine->reset.reset = execlists_reset;

drivers/gpu/drm/i915/gt/intel_reset.c

@@ -9,6 +9,8 @@
 
 #include "i915_drv.h"
 #include "i915_gpu_error.h"
+#include "intel_engine_pm.h"
+#include "intel_gt_pm.h"
 #include "intel_reset.h"
 
 #include "intel_guc.h"
@@ -680,6 +682,7 @@ static void reset_prepare_engine(struct intel_engine_cs *engine)
 	 * written to the powercontext is undefined and so we may lose
 	 * GPU state upon resume, i.e. fail to restart after a reset.
 	 */
+	intel_engine_pm_get(engine);
 	intel_uncore_forcewake_get(engine->uncore, FORCEWAKE_ALL);
 	engine->reset.prepare(engine);
 }
@@ -715,6 +718,7 @@ static void reset_prepare(struct drm_i915_private *i915)
 	struct intel_engine_cs *engine;
 	enum intel_engine_id id;
 
+	intel_gt_pm_get(i915);
 	for_each_engine(engine, i915, id)
 		reset_prepare_engine(engine);
 
@@ -752,48 +756,10 @@ static int gt_reset(struct drm_i915_private *i915,
 static void reset_finish_engine(struct intel_engine_cs *engine)
 {
 	engine->reset.finish(engine);
+	intel_engine_pm_put(engine);
 	intel_uncore_forcewake_put(engine->uncore, FORCEWAKE_ALL);
 }
 
-struct i915_gpu_restart {
-	struct work_struct work;
-	struct drm_i915_private *i915;
-};
-
-static void restart_work(struct work_struct *work)
-{
-	struct i915_gpu_restart *arg = container_of(work, typeof(*arg), work);
-	struct drm_i915_private *i915 = arg->i915;
-	struct intel_engine_cs *engine;
-	enum intel_engine_id id;
-	intel_wakeref_t wakeref;
-
-	wakeref = intel_runtime_pm_get(i915);
-	mutex_lock(&i915->drm.struct_mutex);
-	WRITE_ONCE(i915->gpu_error.restart, NULL);
-
-	for_each_engine(engine, i915, id) {
-		struct i915_request *rq;
-
-		/*
-		 * Ostensibily, we always want a context loaded for powersaving,
-		 * so if the engine is idle after the reset, send a request
-		 * to load our scratch kernel_context.
-		 */
-		if (!intel_engine_is_idle(engine))
-			continue;
-
-		rq = i915_request_create(engine->kernel_context);
-		if (!IS_ERR(rq))
-			i915_request_add(rq);
-	}
-
-	mutex_unlock(&i915->drm.struct_mutex);
-	intel_runtime_pm_put(i915, wakeref);
-
-	kfree(arg);
-}
-
 static void reset_finish(struct drm_i915_private *i915)
 {
 	struct intel_engine_cs *engine;
@@ -803,29 +769,7 @@ static void reset_finish(struct drm_i915_private *i915)
 		reset_finish_engine(engine);
 		intel_engine_signal_breadcrumbs(engine);
 	}
-}
-
-static void reset_restart(struct drm_i915_private *i915)
-{
-	struct i915_gpu_restart *arg;
-
-	/*
-	 * Following the reset, ensure that we always reload context for
-	 * powersaving, and to correct engine->last_retired_context. Since
-	 * this requires us to submit a request, queue a worker to do that
-	 * task for us to evade any locking here.
-	 */
-	if (READ_ONCE(i915->gpu_error.restart))
-		return;
-
-	arg = kmalloc(sizeof(*arg), GFP_KERNEL);
-	if (arg) {
-		arg->i915 = i915;
-		INIT_WORK(&arg->work, restart_work);
-
-		WRITE_ONCE(i915->gpu_error.restart, arg);
-		queue_work(i915->wq, &arg->work);
-	}
+	intel_gt_pm_put(i915);
 }
 
 static void nop_submit_request(struct i915_request *request)
@@ -886,6 +830,7 @@ static void __i915_gem_set_wedged(struct drm_i915_private *i915)
 	 * in nop_submit_request.
 	 */
 	synchronize_rcu_expedited();
+	set_bit(I915_WEDGED, &error->flags);
 
 	/* Mark all executing requests as skipped */
 	for_each_engine(engine, i915, id)
@@ -893,9 +838,6 @@ static void __i915_gem_set_wedged(struct drm_i915_private *i915)
 
 	reset_finish(i915);
 
-	smp_mb__before_atomic();
-	set_bit(I915_WEDGED, &error->flags);
-
 	GEM_TRACE("end\n");
 }
 
@@ -953,7 +895,7 @@ static bool __i915_gem_unset_wedged(struct drm_i915_private *i915)
 	}
 	mutex_unlock(&i915->gt.timelines.mutex);
 
-	intel_engines_sanitize(i915, false);
+	intel_gt_sanitize(i915, false);
 
 	/*
 	 * Undo nop_submit_request. We prevent all new i915 requests from
@@ -1031,7 +973,6 @@ void i915_reset(struct drm_i915_private *i915,
 	GEM_TRACE("flags=%lx\n", error->flags);
 
 	might_sleep();
-	assert_rpm_wakelock_held(i915);
 	GEM_BUG_ON(!test_bit(I915_RESET_BACKOFF, &error->flags));
 
 	/* Clear any previous failed attempts at recovery. Time to try again. */
@@ -1084,8 +1025,6 @@ void i915_reset(struct drm_i915_private *i915,
 
 finish:
 	reset_finish(i915);
-	if (!__i915_wedged(error))
-		reset_restart(i915);
 	return;
 
 taint:
@@ -1134,6 +1073,9 @@ int i915_reset_engine(struct intel_engine_cs *engine, const char *msg)
 	GEM_TRACE("%s flags=%lx\n", engine->name, error->flags);
 	GEM_BUG_ON(!test_bit(I915_RESET_ENGINE + engine->id, &error->flags));
 
+	if (!intel_wakeref_active(&engine->wakeref))
+		return 0;
+
 	reset_prepare_engine(engine);
 
 	if (msg)
@@ -1165,7 +1107,7 @@ int i915_reset_engine(struct intel_engine_cs *engine, const char *msg)
 	 * have been reset to their default values. Follow the init_ring
 	 * process to program RING_MODE, HWSP and re-enable submission.
 	 */
-	ret = engine->init_hw(engine);
+	ret = engine->resume(engine);
 	if (ret)
 		goto out;
 
@@ -1422,25 +1364,6 @@ int i915_terminally_wedged(struct drm_i915_private *i915)
 	return __i915_wedged(error) ? -EIO : 0;
 }
 
-bool i915_reset_flush(struct drm_i915_private *i915)
-{
-	int err;
-
-	cancel_delayed_work_sync(&i915->gpu_error.hangcheck_work);
-
-	flush_workqueue(i915->wq);
-	GEM_BUG_ON(READ_ONCE(i915->gpu_error.restart));
-
-	mutex_lock(&i915->drm.struct_mutex);
-	err = i915_gem_wait_for_idle(i915,
-				     I915_WAIT_LOCKED |
-				     I915_WAIT_FOR_IDLE_BOOST,
-				     MAX_SCHEDULE_TIMEOUT);
-	mutex_unlock(&i915->drm.struct_mutex);
-
-	return !err;
-}
-
 static void i915_wedge_me(struct work_struct *work)
 {
 	struct i915_wedge_me *w = container_of(work, typeof(*w), work.work);

drivers/gpu/drm/i915/gt/intel_reset.h

@@ -34,7 +34,6 @@ int i915_reset_engine(struct intel_engine_cs *engine,
 		      const char *reason);
 
 void i915_reset_request(struct i915_request *rq, bool guilty);
-bool i915_reset_flush(struct drm_i915_private *i915);
 
 int __must_check i915_reset_trylock(struct drm_i915_private *i915);
 void i915_reset_unlock(struct drm_i915_private *i915, int tag);

drivers/gpu/drm/i915/gt/intel_ringbuffer.c

@@ -637,12 +637,15 @@ static bool stop_ring(struct intel_engine_cs *engine)
 	return (ENGINE_READ(engine, RING_HEAD) & HEAD_ADDR) == 0;
 }
 
-static int init_ring_common(struct intel_engine_cs *engine)
+static int xcs_resume(struct intel_engine_cs *engine)
 {
 	struct drm_i915_private *dev_priv = engine->i915;
 	struct intel_ring *ring = engine->buffer;
 	int ret = 0;
 
+	GEM_TRACE("%s: ring:{HEAD:%04x, TAIL:%04x}\n",
+		  engine->name, ring->head, ring->tail);
+
 	intel_uncore_forcewake_get(engine->uncore, FORCEWAKE_ALL);
 
 	if (!stop_ring(engine)) {
@@ -827,7 +830,7 @@ static int intel_rcs_ctx_init(struct i915_request *rq)
 	return 0;
 }
 
-static int init_render_ring(struct intel_engine_cs *engine)
+static int rcs_resume(struct intel_engine_cs *engine)
 {
 	struct drm_i915_private *dev_priv = engine->i915;
 
@@ -869,7 +872,7 @@ static int init_render_ring(struct intel_engine_cs *engine)
 	if (IS_GEN_RANGE(dev_priv, 6, 7))
 		I915_WRITE(INSTPM, _MASKED_BIT_ENABLE(INSTPM_FORCE_ORDERING));
 
-	return init_ring_common(engine);
+	return xcs_resume(engine);
 }
 
 static void cancel_requests(struct intel_engine_cs *engine)
@@ -2201,7 +2204,7 @@ static void intel_ring_default_vfuncs(struct drm_i915_private *dev_priv,
 
 	intel_ring_init_irq(dev_priv, engine);
 
-	engine->init_hw = init_ring_common;
+	engine->resume = xcs_resume;
 	engine->reset.prepare = reset_prepare;
 	engine->reset.reset = reset_ring;
 	engine->reset.finish = reset_finish;
@@ -2263,7 +2266,7 @@ int intel_init_render_ring_buffer(struct intel_engine_cs *engine)
 	if (IS_HASWELL(dev_priv))
 		engine->emit_bb_start = hsw_emit_bb_start;
 
-	engine->init_hw = init_render_ring;
+	engine->resume = rcs_resume;
 
 	ret = intel_init_ring_buffer(engine);
 	if (ret)

drivers/gpu/drm/i915/gt/mock_engine.c

@@ -24,6 +24,7 @@
 
 #include "i915_drv.h"
 #include "intel_context.h"
+#include "intel_engine_pm.h"
 
 #include "mock_engine.h"
 #include "selftests/mock_request.h"
@@ -268,6 +269,8 @@ struct intel_engine_cs *mock_engine(struct drm_i915_private *i915,
 	i915_timeline_set_subclass(&engine->base.timeline, TIMELINE_ENGINE);
 
 	intel_engine_init_breadcrumbs(&engine->base);
+	intel_engine_init_execlists(&engine->base);
+	intel_engine_init__pm(&engine->base);
 
 	/* fake hw queue */
 	spin_lock_init(&engine->hw_lock);

drivers/gpu/drm/i915/gt/selftest_hangcheck.c

@@ -24,6 +24,8 @@
 
 #include <linux/kthread.h>
 
+#include "intel_engine_pm.h"
+
 #include "i915_selftest.h"
 #include "selftests/i915_random.h"
 #include "selftests/igt_flush_test.h"
@@ -479,19 +481,6 @@ static int igt_reset_nop(void *arg)
 			break;
 		}
 
-		if (!i915_reset_flush(i915)) {
-			struct drm_printer p =
-				drm_info_printer(i915->drm.dev);
-
-			pr_err("%s failed to idle after reset\n",
-			       engine->name);
-			intel_engine_dump(engine, &p,
-					  "%s\n", engine->name);
-
-			err = -EIO;
-			break;
-		}
-
 		err = igt_flush_test(i915, 0);
 		if (err)
 			break;
@@ -594,19 +583,6 @@ static int igt_reset_nop_engine(void *arg)
 				err = -EINVAL;
 				break;
 			}
-
-			if (!i915_reset_flush(i915)) {
-				struct drm_printer p =
-					drm_info_printer(i915->drm.dev);
-
-				pr_err("%s failed to idle after reset\n",
-				       engine->name);
-				intel_engine_dump(engine, &p,
-						  "%s\n", engine->name);
-
-				err = -EIO;
-				break;
-			}
 		} while (time_before(jiffies, end_time));
 		clear_bit(I915_RESET_ENGINE + id, &i915->gpu_error.flags);
 		pr_info("%s(%s): %d resets\n", __func__, engine->name, count);
@@ -669,6 +645,7 @@ static int __igt_reset_engine(struct drm_i915_private *i915, bool active)
 		reset_engine_count = i915_reset_engine_count(&i915->gpu_error,
 							     engine);
 
+		intel_engine_pm_get(engine);
 		set_bit(I915_RESET_ENGINE + id, &i915->gpu_error.flags);
 		do {
 			if (active) {
@@ -721,21 +698,9 @@ static int __igt_reset_engine(struct drm_i915_private *i915, bool active)
 				err = -EINVAL;
 				break;
 			}
-
-			if (!i915_reset_flush(i915)) {
-				struct drm_printer p =
-					drm_info_printer(i915->drm.dev);
-
-				pr_err("%s failed to idle after reset\n",
-				       engine->name);
-				intel_engine_dump(engine, &p,
-						  "%s\n", engine->name);
-
-				err = -EIO;
-				break;
-			}
 		} while (time_before(jiffies, end_time));
 		clear_bit(I915_RESET_ENGINE + id, &i915->gpu_error.flags);
+		intel_engine_pm_put(engine);
 
 		if (err)
 			break;
@@ -942,6 +907,7 @@ static int __igt_reset_engines(struct drm_i915_private *i915,
 			get_task_struct(tsk);
 		}
 
+		intel_engine_pm_get(engine);
 		set_bit(I915_RESET_ENGINE + id, &i915->gpu_error.flags);
 		do {
 			struct i915_request *rq = NULL;
@@ -1018,6 +984,7 @@ static int __igt_reset_engines(struct drm_i915_private *i915,
 			}
 		} while (time_before(jiffies, end_time));
 		clear_bit(I915_RESET_ENGINE + id, &i915->gpu_error.flags);
+		intel_engine_pm_put(engine);
 		pr_info("i915_reset_engine(%s:%s): %lu resets\n",
 			engine->name, test_name, count);
 
@@ -1069,7 +1036,9 @@ static int __igt_reset_engines(struct drm_i915_private *i915,
 		if (err)
 			break;
 
-		err = igt_flush_test(i915, 0);
+		mutex_lock(&i915->drm.struct_mutex);
+		err = igt_flush_test(i915, I915_WAIT_LOCKED);
+		mutex_unlock(&i915->drm.struct_mutex);
 		if (err)
 			break;
 	}

drivers/gpu/drm/i915/gt/selftest_workarounds.c

@@ -71,7 +71,6 @@ read_nonprivs(struct i915_gem_context *ctx, struct intel_engine_cs *engine)
 {
 	const u32 base = engine->mmio_base;
 	struct drm_i915_gem_object *result;
-	intel_wakeref_t wakeref;
 	struct i915_request *rq;
 	struct i915_vma *vma;
 	u32 srm, *cs;
@@ -103,9 +102,7 @@ read_nonprivs(struct i915_gem_context *ctx, struct intel_engine_cs *engine)
 	if (err)
 		goto err_obj;
 
-	rq = ERR_PTR(-ENODEV);
-	with_intel_runtime_pm(engine->i915, wakeref)
-		rq = i915_request_alloc(engine, ctx);
+	rq = i915_request_alloc(engine, ctx);
 	if (IS_ERR(rq)) {
 		err = PTR_ERR(rq);
 		goto err_pin;

drivers/gpu/drm/i915/i915_debugfs.c

@@ -2041,8 +2041,7 @@ static int i915_rps_boost_info(struct seq_file *m, void *data)
 	}
 
 	seq_printf(m, "RPS enabled? %d\n", rps->enabled);
-	seq_printf(m, "GPU busy? %s [%d requests]\n",
-		   yesno(dev_priv->gt.awake), dev_priv->gt.active_requests);
+	seq_printf(m, "GPU busy? %s\n", yesno(dev_priv->gt.awake));
 	seq_printf(m, "Boosts outstanding? %d\n",
 		   atomic_read(&rps->num_waiters));
 	seq_printf(m, "Interactive? %d\n", READ_ONCE(rps->power.interactive));
@@ -2061,9 +2060,7 @@ static int i915_rps_boost_info(struct seq_file *m, void *data)
 
 	seq_printf(m, "Wait boosts: %d\n", atomic_read(&rps->boosts));
 
-	if (INTEL_GEN(dev_priv) >= 6 &&
-	    rps->enabled &&
-	    dev_priv->gt.active_requests) {
+	if (INTEL_GEN(dev_priv) >= 6 && rps->enabled && dev_priv->gt.awake) {
 		u32 rpup, rpupei;
 		u32 rpdown, rpdownei;
 
@@ -3093,9 +3090,9 @@ static int i915_engine_info(struct seq_file *m, void *unused)
 
 	wakeref = intel_runtime_pm_get(dev_priv);
 
-	seq_printf(m, "GT awake? %s\n", yesno(dev_priv->gt.awake));
-	seq_printf(m, "Global active requests: %d\n",
-		   dev_priv->gt.active_requests);
+	seq_printf(m, "GT awake? %s [%d]\n",
+		   yesno(dev_priv->gt.awake),
+		   atomic_read(&dev_priv->gt.wakeref.count));
 	seq_printf(m, "CS timestamp frequency: %u kHz\n",
 		   RUNTIME_INFO(dev_priv)->cs_timestamp_frequency_khz);
 
@@ -3941,8 +3938,7 @@ i915_drop_caches_set(void *data, u64 val)
 
 	if (val & DROP_IDLE) {
 		do {
-			if (READ_ONCE(i915->gt.active_requests))
-				flush_delayed_work(&i915->gem.retire_work);
+			flush_delayed_work(&i915->gem.retire_work);
 			drain_delayed_work(&i915->gem.idle_work);
 		} while (READ_ONCE(i915->gt.awake));
 	}

drivers/gpu/drm/i915/i915_drv.c

@@ -47,8 +47,9 @@
 #include <drm/drm_probe_helper.h>
 #include <drm/i915_drm.h>
 
-#include "gt/intel_workarounds.h"
+#include "gt/intel_gt_pm.h"
 #include "gt/intel_reset.h"
+#include "gt/intel_workarounds.h"
 
 #include "i915_drv.h"
 #include "i915_pmu.h"
@@ -2323,7 +2324,7 @@ static int i915_drm_resume_early(struct drm_device *dev)
 
 	intel_power_domains_resume(dev_priv);
 
-	intel_engines_sanitize(dev_priv, true);
+	intel_gt_sanitize(dev_priv, true);
 
 	enable_rpm_wakeref_asserts(dev_priv);
 

drivers/gpu/drm/i915/i915_drv.h

@@ -2006,10 +2006,10 @@ struct drm_i915_private {
 			struct list_head hwsp_free_list;
 		} timelines;
 
-		intel_engine_mask_t active_engines;
 		struct list_head active_rings;
 		struct list_head closed_vma;
-		u32 active_requests;
+
+		struct intel_wakeref wakeref;
 
 		/**
 		 * Is the GPU currently considered idle, or busy executing
@@ -2020,12 +2020,16 @@ struct drm_i915_private {
 		 */
 		intel_wakeref_t awake;
 
+		struct blocking_notifier_head pm_notifications;
+
 		ktime_t last_init_time;
 
 		struct i915_vma *scratch;
 	} gt;
 
 	struct {
+		struct notifier_block pm_notifier;
+
 		/**
 		 * We leave the user IRQ off as much as possible,
 		 * but this means that requests will finish and never

drivers/gpu/drm/i915/i915_gem.c

@@ -39,6 +39,8 @@
 #include <linux/dma-buf.h>
 #include <linux/mman.h>
 
+#include "gt/intel_engine_pm.h"
+#include "gt/intel_gt_pm.h"
 #include "gt/intel_mocs.h"
 #include "gt/intel_reset.h"
 #include "gt/intel_workarounds.h"
@@ -2888,9 +2890,6 @@ wait_for_timelines(struct drm_i915_private *i915,
 	struct i915_gt_timelines *gt = &i915->gt.timelines;
 	struct i915_timeline *tl;
 
-	if (!READ_ONCE(i915->gt.active_requests))
-		return timeout;
-
 	mutex_lock(&gt->mutex);
 	list_for_each_entry(tl, &gt->active_list, link) {
 		struct i915_request *rq;
@@ -2930,9 +2929,10 @@ wait_for_timelines(struct drm_i915_private *i915,
 int i915_gem_wait_for_idle(struct drm_i915_private *i915,
 			   unsigned int flags, long timeout)
 {
-	GEM_TRACE("flags=%x (%s), timeout=%ld%s\n",
+	GEM_TRACE("flags=%x (%s), timeout=%ld%s, awake?=%s\n",
 		  flags, flags & I915_WAIT_LOCKED ? "locked" : "unlocked",
-		  timeout, timeout == MAX_SCHEDULE_TIMEOUT ? " (forever)" : "");
+		  timeout, timeout == MAX_SCHEDULE_TIMEOUT ? " (forever)" : "",
+		  yesno(i915->gt.awake));
 
 	/* If the device is asleep, we have no requests outstanding */
 	if (!READ_ONCE(i915->gt.awake))
@@ -4154,7 +4154,7 @@ void i915_gem_sanitize(struct drm_i915_private *i915)
 	 * it may impact the display and we are uncertain about the stability
 	 * of the reset, so this could be applied to even earlier gen.
 	 */
-	intel_engines_sanitize(i915, false);
+	intel_gt_sanitize(i915, false);
 
 	intel_uncore_forcewake_put(&i915->uncore, FORCEWAKE_ALL);
 	intel_runtime_pm_put(i915, wakeref);
@@ -4212,27 +4212,6 @@ static void init_unused_rings(struct drm_i915_private *dev_priv)
 	}
 }
 
-static int __i915_gem_restart_engines(void *data)
-{
-	struct drm_i915_private *i915 = data;
-	struct intel_engine_cs *engine;
-	enum intel_engine_id id;
-	int err;
-
-	for_each_engine(engine, i915, id) {
-		err = engine->init_hw(engine);
-		if (err) {
-			DRM_ERROR("Failed to restart %s (%d)\n",
-				  engine->name, err);
-			return err;
-		}
-	}
-
-	intel_engines_set_scheduler_caps(i915);
-
-	return 0;
-}
-
 int i915_gem_init_hw(struct drm_i915_private *dev_priv)
 {
 	int ret;
@@ -4291,12 +4270,13 @@ int i915_gem_init_hw(struct drm_i915_private *dev_priv)
 	intel_mocs_init_l3cc_table(dev_priv);
 
 	/* Only when the HW is re-initialised, can we replay the requests */
-	ret = __i915_gem_restart_engines(dev_priv);
+	ret = intel_engines_resume(dev_priv);
 	if (ret)
 		goto cleanup_uc;
 
 	intel_uncore_forcewake_put(&dev_priv->uncore, FORCEWAKE_ALL);
 
+	intel_engines_set_scheduler_caps(dev_priv);
 	return 0;
 
 cleanup_uc:
@@ -4602,6 +4582,7 @@ int i915_gem_init(struct drm_i915_private *dev_priv)
 err_init_hw:
 	mutex_unlock(&dev_priv->drm.struct_mutex);
 
+	i915_gem_set_wedged(dev_priv);
 	i915_gem_suspend(dev_priv);
 	i915_gem_suspend_late(dev_priv);
 
@@ -4663,6 +4644,8 @@ int i915_gem_init(struct drm_i915_private *dev_priv)
 
 void i915_gem_fini(struct drm_i915_private *dev_priv)
 {
+	GEM_BUG_ON(dev_priv->gt.awake);
+
 	i915_gem_suspend_late(dev_priv);
 	intel_disable_gt_powersave(dev_priv);
 
@@ -4757,6 +4740,8 @@ int i915_gem_init_early(struct drm_i915_private *dev_priv)
 {
 	int err;
 
+	intel_gt_pm_init(dev_priv);
+
 	INIT_LIST_HEAD(&dev_priv->gt.active_rings);
 	INIT_LIST_HEAD(&dev_priv->gt.closed_vma);
 

drivers/gpu/drm/i915/i915_gem.h

@@ -75,9 +75,6 @@ struct drm_i915_private;
 
 #define I915_GEM_IDLE_TIMEOUT (HZ / 5)
 
-void i915_gem_park(struct drm_i915_private *i915);
-void i915_gem_unpark(struct drm_i915_private *i915);
-
 static inline void __tasklet_disable_sync_once(struct tasklet_struct *t)
 {
 	if (!atomic_fetch_inc(&t->count))

drivers/gpu/drm/i915/i915_gem_context.c

@@ -824,26 +824,6 @@ int i915_gem_vm_destroy_ioctl(struct drm_device *dev, void *data,
 	return 0;
 }
 
-static struct i915_request *
-last_request_on_engine(struct i915_timeline *timeline,
-		       struct intel_engine_cs *engine)
-{
-	struct i915_request *rq;
-
-	GEM_BUG_ON(timeline == &engine->timeline);
-
-	rq = i915_active_request_raw(&timeline->last_request,
-				     &engine->i915->drm.struct_mutex);
-	if (rq && rq->engine->mask & engine->mask) {
-		GEM_TRACE("last request on engine %s: %llx:%llu\n",
-			  engine->name, rq->fence.context, rq->fence.seqno);
-		GEM_BUG_ON(rq->timeline != timeline);
-		return rq;
-	}
-
-	return NULL;
-}
-
 struct context_barrier_task {
 	struct i915_active base;
 	void (*task)(void *data);
@@ -871,7 +851,6 @@ static int context_barrier_task(struct i915_gem_context *ctx,
 	struct drm_i915_private *i915 = ctx->i915;
 	struct context_barrier_task *cb;
 	struct intel_context *ce, *next;
-	intel_wakeref_t wakeref;
 	int err = 0;
 
 	lockdep_assert_held(&i915->drm.struct_mutex);
@@ -884,7 +863,6 @@ static int context_barrier_task(struct i915_gem_context *ctx,
 	i915_active_init(i915, &cb->base, cb_retire);
 	i915_active_acquire(&cb->base);
 
-	wakeref = intel_runtime_pm_get(i915);
 	rbtree_postorder_for_each_entry_safe(ce, next, &ctx->hw_contexts, node) {
 		struct intel_engine_cs *engine = ce->engine;
 		struct i915_request *rq;
@@ -914,7 +892,6 @@ static int context_barrier_task(struct i915_gem_context *ctx,
 		if (err)
 			break;
 	}
-	intel_runtime_pm_put(i915, wakeref);
 
 	cb->task = err ? NULL : task; /* caller needs to unwind instead */
 	cb->data = data;
@@ -924,54 +901,6 @@ static int context_barrier_task(struct i915_gem_context *ctx,
 	return err;
 }
 
-int i915_gem_switch_to_kernel_context(struct drm_i915_private *i915,
-				      intel_engine_mask_t mask)
-{
-	struct intel_engine_cs *engine;
-
-	GEM_TRACE("awake?=%s\n", yesno(i915->gt.awake));
-
-	lockdep_assert_held(&i915->drm.struct_mutex);
-	GEM_BUG_ON(!i915->kernel_context);
-
-	/* Inoperable, so presume the GPU is safely pointing into the void! */
-	if (i915_terminally_wedged(i915))
-		return 0;
-
-	for_each_engine_masked(engine, i915, mask, mask) {
-		struct intel_ring *ring;
-		struct i915_request *rq;
-
-		rq = i915_request_create(engine->kernel_context);
-		if (IS_ERR(rq))
-			return PTR_ERR(rq);
-
-		/* Queue this switch after all other activity */
-		list_for_each_entry(ring, &i915->gt.active_rings, active_link) {
-			struct i915_request *prev;
-
-			prev = last_request_on_engine(ring->timeline, engine);
-			if (!prev)
-				continue;
-
-			if (prev->gem_context == i915->kernel_context)
-				continue;
-
-			GEM_TRACE("add barrier on %s for %llx:%lld\n",
-				  engine->name,
-				  prev->fence.context,
-				  prev->fence.seqno);
-			i915_sw_fence_await_sw_fence_gfp(&rq->submit,
-							 &prev->submit,
-							 I915_FENCE_GFP);
-		}
-
-		i915_request_add(rq);
-	}
-
-	return 0;
-}
-
 static int get_ppgtt(struct drm_i915_file_private *file_priv,
 		     struct i915_gem_context *ctx,
 		     struct drm_i915_gem_context_param *args)
@@ -1169,9 +1098,7 @@ static int gen8_emit_rpcs_config(struct i915_request *rq,
 static int
 gen8_modify_rpcs(struct intel_context *ce, struct intel_sseu sseu)
 {
-	struct drm_i915_private *i915 = ce->engine->i915;
 	struct i915_request *rq;
-	intel_wakeref_t wakeref;
 	int ret;
 
 	lockdep_assert_held(&ce->pin_mutex);
@@ -1185,14 +1112,9 @@ gen8_modify_rpcs(struct intel_context *ce, struct intel_sseu sseu)
 	if (!intel_context_is_pinned(ce))
 		return 0;
 
-	/* Submitting requests etc needs the hw awake. */
-	wakeref = intel_runtime_pm_get(i915);
-
 	rq = i915_request_create(ce->engine->kernel_context);
-	if (IS_ERR(rq)) {
-		ret = PTR_ERR(rq);
-		goto out_put;
-	}
+	if (IS_ERR(rq))
+		return PTR_ERR(rq);
 
 	/* Queue this switch after all other activity by this context. */
 	ret = i915_active_request_set(&ce->ring->timeline->last_request, rq);
@@ -1216,9 +1138,6 @@ gen8_modify_rpcs(struct intel_context *ce, struct intel_sseu sseu)
 
 out_add:
 	i915_request_add(rq);
-out_put:
-	intel_runtime_pm_put(i915, wakeref);
-
 	return ret;
 }
 

drivers/gpu/drm/i915/i915_gem_context.h

@@ -141,10 +141,6 @@ int i915_gem_context_open(struct drm_i915_private *i915,
 			  struct drm_file *file);
 void i915_gem_context_close(struct drm_file *file);
 
-int i915_switch_context(struct i915_request *rq);
-int i915_gem_switch_to_kernel_context(struct drm_i915_private *i915,
-				      intel_engine_mask_t engine_mask);
-
 void i915_gem_context_release(struct kref *ctx_ref);
 struct i915_gem_context *
 i915_gem_context_create_gvt(struct drm_device *dev);

drivers/gpu/drm/i915/i915_gem_evict.c

@@ -36,15 +36,8 @@ I915_SELFTEST_DECLARE(static struct igt_evict_ctl {
 	bool fail_if_busy:1;
 } igt_evict_ctl;)
 
-static bool ggtt_is_idle(struct drm_i915_private *i915)
-{
-	return !i915->gt.active_requests;
-}
-
 static int ggtt_flush(struct drm_i915_private *i915)
 {
-	int err;
-
 	/*
 	 * Not everything in the GGTT is tracked via vma (otherwise we
 	 * could evict as required with minimal stalling) so we are forced
@@ -52,19 +45,10 @@ static int ggtt_flush(struct drm_i915_private *i915)
 	 * the hopes that we can then remove contexts and the like only
 	 * bound by their active reference.
 	 */
-	err = i915_gem_switch_to_kernel_context(i915, i915->gt.active_engines);
-	if (err)
-		return err;
-
-	err = i915_gem_wait_for_idle(i915,
-				     I915_WAIT_INTERRUPTIBLE |
-				     I915_WAIT_LOCKED,
-				     MAX_SCHEDULE_TIMEOUT);
-	if (err)
-		return err;
-
-	GEM_BUG_ON(!ggtt_is_idle(i915));
-	return 0;
+	return i915_gem_wait_for_idle(i915,
+				      I915_WAIT_INTERRUPTIBLE |
+				      I915_WAIT_LOCKED,
+				      MAX_SCHEDULE_TIMEOUT);
 }
 
 static bool
@@ -222,24 +206,17 @@ i915_gem_evict_something(struct i915_address_space *vm,
 	 * us a termination condition, when the last retired context is
 	 * the kernel's there is no more we can evict.
 	 */
-	if (!ggtt_is_idle(dev_priv)) {
-		if (I915_SELFTEST_ONLY(igt_evict_ctl.fail_if_busy))
-			return -EBUSY;
+	if (I915_SELFTEST_ONLY(igt_evict_ctl.fail_if_busy))
+		return -EBUSY;
 
-		ret = ggtt_flush(dev_priv);
-		if (ret)
-			return ret;
+	ret = ggtt_flush(dev_priv);
+	if (ret)
+		return ret;
 
-		cond_resched();
-		goto search_again;
-	}
+	cond_resched();
 
-	/*
-	 * If we still have pending pageflip completions, drop
-	 * back to userspace to give our workqueues time to
-	 * acquire our locks and unpin the old scanouts.
-	 */
-	return intel_has_pending_fb_unpin(dev_priv) ? -EAGAIN : -ENOSPC;
+	flags |= PIN_NONBLOCK;
+	goto search_again;
 
 found:
 	/* drm_mm doesn't allow any other other operations while

drivers/gpu/drm/i915/i915_gem_pm.c

@@ -4,136 +4,63 @@
  * Copyright © 2019 Intel Corporation
  */
 
+#include "gt/intel_gt_pm.h"
+
 #include "i915_drv.h"
 #include "i915_gem_pm.h"
 #include "i915_globals.h"
-#include "intel_pm.h"
 
-static void __i915_gem_park(struct drm_i915_private *i915)
+static void i915_gem_park(struct drm_i915_private *i915)
 {
-	intel_wakeref_t wakeref;
-
-	GEM_TRACE("\n");
+	struct intel_engine_cs *engine;
+	enum intel_engine_id id;
 
 	lockdep_assert_held(&i915->drm.struct_mutex);
-	GEM_BUG_ON(i915->gt.active_requests);
-	GEM_BUG_ON(!list_empty(&i915->gt.active_rings));
-
-	if (!i915->gt.awake)
-		return;
-
-	/*
-	 * Be paranoid and flush a concurrent interrupt to make sure
-	 * we don't reactivate any irq tasklets after parking.
-	 *
-	 * FIXME: Note that even though we have waited for execlists to be idle,
-	 * there may still be an in-flight interrupt even though the CSB
-	 * is now empty. synchronize_irq() makes sure that a residual interrupt
-	 * is completed before we continue, but it doesn't prevent the HW from
-	 * raising a spurious interrupt later. To complete the shield we should
-	 * coordinate disabling the CS irq with flushing the interrupts.
-	 */
-	synchronize_irq(i915->drm.irq);
-
-	intel_engines_park(i915);
-	i915_timelines_park(i915);
-
-	i915_pmu_gt_parked(i915);
-	i915_vma_parked(i915);
-
-	wakeref = fetch_and_zero(&i915->gt.awake);
-	GEM_BUG_ON(!wakeref);
-
-	if (INTEL_GEN(i915) >= 6)
-		gen6_rps_idle(i915);
-
-	intel_display_power_put(i915, POWER_DOMAIN_GT_IRQ, wakeref);
-
-	i915_globals_park();
-}
-
-static bool switch_to_kernel_context_sync(struct drm_i915_private *i915,
-					  unsigned long mask)
-{
-	bool result = true;
-
-	/*
-	 * Even if we fail to switch, give whatever is running a small chance
-	 * to save itself before we report the failure. Yes, this may be a
-	 * false positive due to e.g. ENOMEM, caveat emptor!
-	 */
-	if (i915_gem_switch_to_kernel_context(i915, mask))
-		result = false;
 
-	if (i915_gem_wait_for_idle(i915,
-				   I915_WAIT_LOCKED |
-				   I915_WAIT_FOR_IDLE_BOOST,
-				   I915_GEM_IDLE_TIMEOUT))
-		result = false;
+	for_each_engine(engine, i915, id) {
+		/*
+		 * We are committed now to parking the engines, make sure there
+		 * will be no more interrupts arriving later and the engines
+		 * are truly idle.
+		 */
+		if (wait_for(intel_engine_is_idle(engine), 10)) {
+			struct drm_printer p = drm_debug_printer(__func__);
 
-	if (!result) {
-		if (i915_modparams.reset) { /* XXX hide warning from gem_eio */
 			dev_err(i915->drm.dev,
-				"Failed to idle engines, declaring wedged!\n");
-			GEM_TRACE_DUMP();
+				"%s is not idle before parking\n",
+				engine->name);
+			intel_engine_dump(engine, &p, NULL);
 		}
+		tasklet_kill(&engine->execlists.tasklet);
 
-		/* Forcibly cancel outstanding work and leave the gpu quiet. */
-		i915_gem_set_wedged(i915);
+		i915_gem_batch_pool_fini(&engine->batch_pool);
 	}
 
-	i915_retire_requests(i915); /* ensure we flush after wedging */
-	return result;
+	i915_timelines_park(i915);
+	i915_vma_parked(i915);
+
+	i915_globals_park();
 }
 
 static void idle_work_handler(struct work_struct *work)
 {
 	struct drm_i915_private *i915 =
 		container_of(work, typeof(*i915), gem.idle_work.work);
-	bool rearm_hangcheck;
-
-	if (!READ_ONCE(i915->gt.awake))
-		return;
-
-	if (READ_ONCE(i915->gt.active_requests))
-		return;
-
-	rearm_hangcheck =
-		cancel_delayed_work_sync(&i915->gpu_error.hangcheck_work);
 
 	if (!mutex_trylock(&i915->drm.struct_mutex)) {
 		/* Currently busy, come back later */
 		mod_delayed_work(i915->wq,
 				 &i915->gem.idle_work,
 				 msecs_to_jiffies(50));
-		goto out_rearm;
+		return;
 	}
 
-	/*
-	 * Flush out the last user context, leaving only the pinned
-	 * kernel context resident. Should anything unfortunate happen
-	 * while we are idle (such as the GPU being power cycled), no users
-	 * will be harmed.
-	 */
-	if (!work_pending(&i915->gem.idle_work.work) &&
-	    !i915->gt.active_requests) {
-		++i915->gt.active_requests; /* don't requeue idle */
-
-		switch_to_kernel_context_sync(i915, i915->gt.active_engines);
-
-		if (!--i915->gt.active_requests) {
-			__i915_gem_park(i915);
-			rearm_hangcheck = false;
-		}
-	}
+	intel_wakeref_lock(&i915->gt.wakeref);
+	if (!intel_wakeref_active(&i915->gt.wakeref))
+		i915_gem_park(i915);
+	intel_wakeref_unlock(&i915->gt.wakeref);
 
 	mutex_unlock(&i915->drm.struct_mutex);
-
-out_rearm:
-	if (rearm_hangcheck) {
-		GEM_BUG_ON(!i915->gt.awake);
-		i915_queue_hangcheck(i915);
-	}
 }
 
 static void retire_work_handler(struct work_struct *work)
@@ -147,97 +74,76 @@ static void retire_work_handler(struct work_struct *work)
 		mutex_unlock(&i915->drm.struct_mutex);
 	}
 
-	/*
-	 * Keep the retire handler running until we are finally idle.
-	 * We do not need to do this test under locking as in the worst-case
-	 * we queue the retire worker once too often.
-	 */
-	if (READ_ONCE(i915->gt.awake))
+	if (intel_wakeref_active(&i915->gt.wakeref))
 		queue_delayed_work(i915->wq,
 				   &i915->gem.retire_work,
 				   round_jiffies_up_relative(HZ));
 }
 
-void i915_gem_park(struct drm_i915_private *i915)
+static int pm_notifier(struct notifier_block *nb,
+		       unsigned long action,
+		       void *data)
 {
-	GEM_TRACE("\n");
+	struct drm_i915_private *i915 =
+		container_of(nb, typeof(*i915), gem.pm_notifier);
 
-	lockdep_assert_held(&i915->drm.struct_mutex);
-	GEM_BUG_ON(i915->gt.active_requests);
+	switch (action) {
+	case INTEL_GT_UNPARK:
+		i915_globals_unpark();
+		queue_delayed_work(i915->wq,
+				   &i915->gem.retire_work,
+				   round_jiffies_up_relative(HZ));
+		break;
 
-	if (!i915->gt.awake)
-		return;
+	case INTEL_GT_PARK:
+		mod_delayed_work(i915->wq,
+				 &i915->gem.idle_work,
+				 msecs_to_jiffies(100));
+		break;
+	}
 
-	/* Defer the actual call to __i915_gem_park() to prevent ping-pongs */
-	mod_delayed_work(i915->wq, &i915->gem.idle_work, msecs_to_jiffies(100));
+	return NOTIFY_OK;
 }
 
-void i915_gem_unpark(struct drm_i915_private *i915)
+static bool switch_to_kernel_context_sync(struct drm_i915_private *i915)
 {
-	GEM_TRACE("\n");
-
-	lockdep_assert_held(&i915->drm.struct_mutex);
-	GEM_BUG_ON(!i915->gt.active_requests);
-	assert_rpm_wakelock_held(i915);
-
-	if (i915->gt.awake)
-		return;
-
-	/*
-	 * It seems that the DMC likes to transition between the DC states a lot
-	 * when there are no connected displays (no active power domains) during
-	 * command submission.
-	 *
-	 * This activity has negative impact on the performance of the chip with
-	 * huge latencies observed in the interrupt handler and elsewhere.
-	 *
-	 * Work around it by grabbing a GT IRQ power domain whilst there is any
-	 * GT activity, preventing any DC state transitions.
-	 */
-	i915->gt.awake = intel_display_power_get(i915, POWER_DOMAIN_GT_IRQ);
-	GEM_BUG_ON(!i915->gt.awake);
-
-	i915_globals_unpark();
-
-	intel_enable_gt_powersave(i915);
-	i915_update_gfx_val(i915);
-	if (INTEL_GEN(i915) >= 6)
-		gen6_rps_busy(i915);
-	i915_pmu_gt_unparked(i915);
-
-	intel_engines_unpark(i915);
+	bool result = true;
 
-	i915_queue_hangcheck(i915);
+	do {
+		if (i915_gem_wait_for_idle(i915,
+					   I915_WAIT_LOCKED |
+					   I915_WAIT_FOR_IDLE_BOOST,
+					   I915_GEM_IDLE_TIMEOUT) == -ETIME) {
+			/* XXX hide warning from gem_eio */
+			if (i915_modparams.reset) {
+				dev_err(i915->drm.dev,
+					"Failed to idle engines, declaring wedged!\n");
+				GEM_TRACE_DUMP();
+			}
+
+			/*
+			 * Forcibly cancel outstanding work and leave
+			 * the gpu quiet.
+			 */
+			i915_gem_set_wedged(i915);
+			result = false;
+		}
+	} while (i915_retire_requests(i915) && result);
 
-	queue_delayed_work(i915->wq,
-			   &i915->gem.retire_work,
-			   round_jiffies_up_relative(HZ));
+	GEM_BUG_ON(i915->gt.awake);
+	return result;
 }
 
 bool i915_gem_load_power_context(struct drm_i915_private *i915)
 {
-	/* Force loading the kernel context on all engines */
-	if (!switch_to_kernel_context_sync(i915, ALL_ENGINES))
-		return false;
-
-	/*
-	 * Immediately park the GPU so that we enable powersaving and
-	 * treat it as idle. The next time we issue a request, we will
-	 * unpark and start using the engine->pinned_default_state, otherwise
-	 * it is in limbo and an early reset may fail.
-	 */
-	__i915_gem_park(i915);
-
-	return true;
+	return switch_to_kernel_context_sync(i915);
 }
 
 void i915_gem_suspend(struct drm_i915_private *i915)
 {
-	intel_wakeref_t wakeref;
-
 	GEM_TRACE("\n");
 
-	wakeref = intel_runtime_pm_get(i915);
+	flush_workqueue(i915->wq);
 
 	mutex_lock(&i915->drm.struct_mutex);
 
@@ -250,10 +156,16 @@ void i915_gem_suspend(struct drm_i915_private *i915)
 	 * state. Fortunately, the kernel_context is disposable and we do
 	 * not rely on its state.
 	 */
-	switch_to_kernel_context_sync(i915, i915->gt.active_engines);
+	switch_to_kernel_context_sync(i915);
 
 	mutex_unlock(&i915->drm.struct_mutex);
-	i915_reset_flush(i915);
+
+	/*
+	 * Assert that we successfully flushed all the work and
+	 * reset the GPU back to its idle, low power state.
+	 */
+	GEM_BUG_ON(i915->gt.awake);
+	cancel_delayed_work_sync(&i915->gpu_error.hangcheck_work);
 
 	drain_delayed_work(&i915->gem.retire_work);
 
@@ -263,17 +175,9 @@ void i915_gem_suspend(struct drm_i915_private *i915)
 	 */
 	drain_delayed_work(&i915->gem.idle_work);
 
-	flush_workqueue(i915->wq);
-
-	/*
-	 * Assert that we successfully flushed all the work and
-	 * reset the GPU back to its idle, low power state.
-	 */
-	GEM_BUG_ON(i915->gt.awake);
+	i915_gem_drain_freed_objects(i915);
 
 	intel_uc_suspend(i915);
-
-	intel_runtime_pm_put(i915, wakeref);
 }
 
 void i915_gem_suspend_late(struct drm_i915_private *i915)
@@ -362,4 +266,8 @@ void i915_gem_init__pm(struct drm_i915_private *i915)
 {
 	INIT_DELAYED_WORK(&i915->gem.idle_work, idle_work_handler);
 	INIT_DELAYED_WORK(&i915->gem.retire_work, retire_work_handler);
+
+	i915->gem.pm_notifier.notifier_call = pm_notifier;
+	blocking_notifier_chain_register(&i915->gt.pm_notifications,
+					 &i915->gem.pm_notifier);
 }

drivers/gpu/drm/i915/i915_gem_pm.h

@@ -17,9 +17,6 @@ void i915_gem_init__pm(struct drm_i915_private *i915);
 bool i915_gem_load_power_context(struct drm_i915_private *i915);
 void i915_gem_resume(struct drm_i915_private *i915);
 
-void i915_gem_unpark(struct drm_i915_private *i915);
-void i915_gem_park(struct drm_i915_private *i915);
-
 void i915_gem_idle_work_handler(struct work_struct *work);
 
 void i915_gem_suspend(struct drm_i915_private *i915);

drivers/gpu/drm/i915/i915_gpu_error.h

@@ -179,8 +179,6 @@ struct i915_gpu_state {
 	struct scatterlist *sgl, *fit;
 };
 
-struct i915_gpu_restart;
-
 struct i915_gpu_error {
 	/* For hangcheck timer */
 #define DRM_I915_HANGCHECK_PERIOD 1500 /* in ms */
@@ -241,8 +239,6 @@ struct i915_gpu_error {
 	wait_queue_head_t reset_queue;
 
 	struct srcu_struct reset_backoff_srcu;
-
-	struct i915_gpu_restart *restart;
 };
 
 struct drm_i915_error_state_buf {

drivers/gpu/drm/i915/i915_request.c

@@ -430,6 +430,8 @@ void __i915_request_submit(struct i915_request *request)
 	/* Transfer from per-context onto the global per-engine timeline */
 	move_to_timeline(request, &engine->timeline);
 
+	engine->serial++;
+
 	trace_i915_request_execute(request);
 }
 
@@ -1145,7 +1147,6 @@ struct i915_request *__i915_request_commit(struct i915_request *rq)
 	list_add_tail(&rq->ring_link, &ring->request_list);
 	if (list_is_first(&rq->ring_link, &ring->request_list))
 		list_add(&ring->active_link, &rq->i915->gt.active_rings);
-	rq->i915->gt.active_engines |= rq->engine->mask;
 	rq->emitted_jiffies = jiffies;
 
 	/*
@@ -1440,21 +1441,20 @@ long i915_request_wait(struct i915_request *rq,
 	return timeout;
 }
 
-void i915_retire_requests(struct drm_i915_private *i915)
+bool i915_retire_requests(struct drm_i915_private *i915)
 {
 	struct intel_ring *ring, *tmp;
 
 	lockdep_assert_held(&i915->drm.struct_mutex);
 
-	if (!i915->gt.active_requests)
-		return;
-
 	list_for_each_entry_safe(ring, tmp,
 				 &i915->gt.active_rings, active_link) {
 		intel_ring_get(ring); /* last rq holds reference! */
 		ring_retire_requests(ring);
 		intel_ring_put(ring);
 	}
+
+	return !list_empty(&i915->gt.active_rings);
 }
 
 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)

drivers/gpu/drm/i915/i915_request.h

@@ -425,6 +425,6 @@ static inline void i915_request_mark_complete(struct i915_request *rq)
 	rq->hwsp_seqno = (u32 *)&rq->fence.seqno; /* decouple from HWSP */
 }
 
-void i915_retire_requests(struct drm_i915_private *i915);
+bool i915_retire_requests(struct drm_i915_private *i915);
 
 #endif /* I915_REQUEST_H */

drivers/gpu/drm/i915/intel_uc.c

@@ -481,26 +481,22 @@ void intel_uc_reset_prepare(struct drm_i915_private *i915)
 	intel_uc_sanitize(i915);
 }
 
-int intel_uc_suspend(struct drm_i915_private *i915)
+void intel_uc_suspend(struct drm_i915_private *i915)
 {
 	struct intel_guc *guc = &i915->guc;
+	intel_wakeref_t wakeref;
 	int err;
 
-	if (!USES_GUC(i915))
-		return 0;
-
 	if (guc->fw.load_status != INTEL_UC_FIRMWARE_SUCCESS)
-		return 0;
-
-	err = intel_guc_suspend(guc);
-	if (err) {
-		DRM_DEBUG_DRIVER("Failed to suspend GuC, err=%d", err);
-		return err;
-	}
+		return;
 
-	guc_disable_communication(guc);
+	with_intel_runtime_pm(i915, wakeref) {
+		err = intel_guc_suspend(guc);
+		if (err)
+			DRM_DEBUG_DRIVER("Failed to suspend GuC, err=%d", err);
 
-	return 0;
+		guc_disable_communication(guc);
+	}
 }
 
 int intel_uc_resume(struct drm_i915_private *i915)

drivers/gpu/drm/i915/intel_uc.h

@@ -39,7 +39,7 @@ void intel_uc_fini_hw(struct drm_i915_private *dev_priv);
 int intel_uc_init(struct drm_i915_private *dev_priv);
 void intel_uc_fini(struct drm_i915_private *dev_priv);
 void intel_uc_reset_prepare(struct drm_i915_private *i915);
-int intel_uc_suspend(struct drm_i915_private *dev_priv);
+void intel_uc_suspend(struct drm_i915_private *i915);
 int intel_uc_resume(struct drm_i915_private *dev_priv);
 
 static inline bool intel_uc_is_using_guc(struct drm_i915_private *i915)

drivers/gpu/drm/i915/selftests/i915_gem.c

@@ -16,26 +16,18 @@ static int switch_to_context(struct drm_i915_private *i915,
 {
 	struct intel_engine_cs *engine;
 	enum intel_engine_id id;
-	intel_wakeref_t wakeref;
-	int err = 0;
-
-	wakeref = intel_runtime_pm_get(i915);
 
 	for_each_engine(engine, i915, id) {
 		struct i915_request *rq;
 
 		rq = i915_request_alloc(engine, ctx);
-		if (IS_ERR(rq)) {
-			err = PTR_ERR(rq);
-			break;
-		}
+		if (IS_ERR(rq))
+			return PTR_ERR(rq);
 
 		i915_request_add(rq);
 	}
 
-	intel_runtime_pm_put(i915, wakeref);
-
-	return err;
+	return 0;
 }
 
 static void trash_stolen(struct drm_i915_private *i915)
@@ -120,7 +112,7 @@ static void pm_resume(struct drm_i915_private *i915)
 	 * that runtime-pm just works.
 	 */
 	with_intel_runtime_pm(i915, wakeref) {
-		intel_engines_sanitize(i915, false);
+		intel_gt_sanitize(i915, false);
 		i915_gem_sanitize(i915);
 		i915_gem_resume(i915);
 	}

drivers/gpu/drm/i915/selftests/i915_gem_context.c

@@ -1608,113 +1608,6 @@ __engine_name(struct drm_i915_private *i915, intel_engine_mask_t engines)
 	return "none";
 }
 
-static int __igt_switch_to_kernel_context(struct drm_i915_private *i915,
-					  struct i915_gem_context *ctx,
-					  intel_engine_mask_t engines)
-{
-	struct intel_engine_cs *engine;
-	intel_engine_mask_t tmp;
-	int pass;
-
-	GEM_TRACE("Testing %s\n", __engine_name(i915, engines));
-	for (pass = 0; pass < 4; pass++) { /* Once busy; once idle; repeat */
-		bool from_idle = pass & 1;
-		int err;
-
-		if (!from_idle) {
-			for_each_engine_masked(engine, i915, engines, tmp) {
-				struct i915_request *rq;
-
-				rq = i915_request_alloc(engine, ctx);
-				if (IS_ERR(rq))
-					return PTR_ERR(rq);
-
-				i915_request_add(rq);
-			}
-		}
-
-		err = i915_gem_switch_to_kernel_context(i915,
-							i915->gt.active_engines);
-		if (err)
-			return err;
-
-		if (!from_idle) {
-			err = i915_gem_wait_for_idle(i915,
-						     I915_WAIT_LOCKED,
-						     MAX_SCHEDULE_TIMEOUT);
-			if (err)
-				return err;
-		}
-
-		if (i915->gt.active_requests) {
-			pr_err("%d active requests remain after switching to kernel context, pass %d (%s) on %s engine%s\n",
-			       i915->gt.active_requests,
-			       pass, from_idle ? "idle" : "busy",
-			       __engine_name(i915, engines),
-			       is_power_of_2(engines) ? "" : "s");
-			return -EINVAL;
-		}
-
-		/* XXX Bonus points for proving we are the kernel context! */
-
-		mutex_unlock(&i915->drm.struct_mutex);
-		drain_delayed_work(&i915->gem.idle_work);
-		mutex_lock(&i915->drm.struct_mutex);
-	}
-
-	if (igt_flush_test(i915, I915_WAIT_LOCKED))
-		return -EIO;
-
-	return 0;
-}
-
-static int igt_switch_to_kernel_context(void *arg)
-{
-	struct drm_i915_private *i915 = arg;
-	struct intel_engine_cs *engine;
-	struct i915_gem_context *ctx;
-	enum intel_engine_id id;
-	intel_wakeref_t wakeref;
-	int err;
-
-	/*
-	 * A core premise of switching to the kernel context is that
-	 * if an engine is already idling in the kernel context, we
-	 * do not emit another request and wake it up. The other being
-	 * that we do indeed end up idling in the kernel context.
-	 */
-
-	mutex_lock(&i915->drm.struct_mutex);
-	wakeref = intel_runtime_pm_get(i915);
-
-	ctx = kernel_context(i915);
-	if (IS_ERR(ctx)) {
-		mutex_unlock(&i915->drm.struct_mutex);
-		return PTR_ERR(ctx);
-	}
-
-	/* First check idling each individual engine */
-	for_each_engine(engine, i915, id) {
-		err = __igt_switch_to_kernel_context(i915, ctx, BIT(id));
-		if (err)
-			goto out_unlock;
-	}
-
-	/* Now en masse */
-	err = __igt_switch_to_kernel_context(i915, ctx, ALL_ENGINES);
-	if (err)
-		goto out_unlock;
-
-out_unlock:
-	GEM_TRACE_DUMP_ON(err);
-
-	intel_runtime_pm_put(i915, wakeref);
-	mutex_unlock(&i915->drm.struct_mutex);
-
-	kernel_context_close(ctx);
-	return err;
-}
-
 static void mock_barrier_task(void *data)
 {
 	unsigned int *counter = data;
@@ -1729,7 +1622,6 @@ static int mock_context_barrier(void *arg)
 	struct drm_i915_private *i915 = arg;
 	struct i915_gem_context *ctx;
 	struct i915_request *rq;
-	intel_wakeref_t wakeref;
 	unsigned int counter;
 	int err;
 
@@ -1772,9 +1664,7 @@ static int mock_context_barrier(void *arg)
 		goto out;
 	}
 
-	rq = ERR_PTR(-ENODEV);
-	with_intel_runtime_pm(i915, wakeref)
-		rq = i915_request_alloc(i915->engine[RCS0], ctx);
+	rq = i915_request_alloc(i915->engine[RCS0], ctx);
 	if (IS_ERR(rq)) {
 		pr_err("Request allocation failed!\n");
 		goto out;
@@ -1824,7 +1714,6 @@ static int mock_context_barrier(void *arg)
 int i915_gem_context_mock_selftests(void)
 {
 	static const struct i915_subtest tests[] = {
-		SUBTEST(igt_switch_to_kernel_context),
 		SUBTEST(mock_context_barrier),
 	};
 	struct drm_i915_private *i915;
@@ -1843,7 +1732,6 @@ int i915_gem_context_mock_selftests(void)
 int i915_gem_context_live_selftests(struct drm_i915_private *dev_priv)
 {
 	static const struct i915_subtest tests[] = {
-		SUBTEST(igt_switch_to_kernel_context),
 		SUBTEST(live_nop_switch),
 		SUBTEST(igt_ctx_exec),
 		SUBTEST(igt_ctx_readonly),

drivers/gpu/drm/i915/selftests/i915_gem_object.c

@@ -24,6 +24,7 @@
 
 #include "../i915_selftest.h"
 
+#include "igt_flush_test.h"
 #include "mock_gem_device.h"
 #include "huge_gem_object.h"
 
@@ -505,19 +506,23 @@ static void disable_retire_worker(struct drm_i915_private *i915)
 {
 	i915_gem_shrinker_unregister(i915);
 
-	mutex_lock(&i915->drm.struct_mutex);
-	if (!i915->gt.active_requests++) {
-		intel_wakeref_t wakeref;
-
-		with_intel_runtime_pm(i915, wakeref)
-			i915_gem_unpark(i915);
-	}
-	mutex_unlock(&i915->drm.struct_mutex);
+	intel_gt_pm_get(i915);
 
 	cancel_delayed_work_sync(&i915->gem.retire_work);
 	cancel_delayed_work_sync(&i915->gem.idle_work);
 }
 
+static void restore_retire_worker(struct drm_i915_private *i915)
+{
+	intel_gt_pm_put(i915);
+
+	mutex_lock(&i915->drm.struct_mutex);
+	igt_flush_test(i915, I915_WAIT_LOCKED);
+	mutex_unlock(&i915->drm.struct_mutex);
+
+	i915_gem_shrinker_register(i915);
+}
+
 static int igt_mmap_offset_exhaustion(void *arg)
 {
 	struct drm_i915_private *i915 = arg;
@@ -615,13 +620,7 @@ static int igt_mmap_offset_exhaustion(void *arg)
 out:
 	drm_mm_remove_node(&resv);
 out_park:
-	mutex_lock(&i915->drm.struct_mutex);
-	if (--i915->gt.active_requests)
-		queue_delayed_work(i915->wq, &i915->gem.retire_work, 0);
-	else
-		queue_delayed_work(i915->wq, &i915->gem.idle_work, 0);
-	mutex_unlock(&i915->drm.struct_mutex);
-	i915_gem_shrinker_register(i915);
+	restore_retire_worker(i915);
 	return err;
 err_obj:
 	i915_gem_object_put(obj);

drivers/gpu/drm/i915/selftests/igt_flush_test.c

@@ -11,23 +11,29 @@
 
 int igt_flush_test(struct drm_i915_private *i915, unsigned int flags)
 {
+	int ret = i915_terminally_wedged(i915) ? -EIO : 0;
+	int repeat = !!(flags & I915_WAIT_LOCKED);
+
 	cond_resched();
 
-	if (flags & I915_WAIT_LOCKED &&
-	    i915_gem_switch_to_kernel_context(i915, i915->gt.active_engines)) {
-		pr_err("Failed to switch back to kernel context; declaring wedged\n");
-		i915_gem_set_wedged(i915);
-	}
+	do {
+		if (i915_gem_wait_for_idle(i915, flags, HZ / 5) == -ETIME) {
+			pr_err("%pS timed out, cancelling all further testing.\n",
+			       __builtin_return_address(0));
 
-	if (i915_gem_wait_for_idle(i915, flags, HZ / 5) == -ETIME) {
-		pr_err("%pS timed out, cancelling all further testing.\n",
-		       __builtin_return_address(0));
+			GEM_TRACE("%pS timed out.\n",
+				  __builtin_return_address(0));
+			GEM_TRACE_DUMP();
 
-		GEM_TRACE("%pS timed out.\n", __builtin_return_address(0));
-		GEM_TRACE_DUMP();
+			i915_gem_set_wedged(i915);
+			repeat = 0;
+			ret = -EIO;
+		}
 
-		i915_gem_set_wedged(i915);
-	}
+		/* Ensure we also flush after wedging. */
+		if (flags & I915_WAIT_LOCKED)
+			i915_retire_requests(i915);
+	} while (repeat--);
 
-	return i915_terminally_wedged(i915);
+	return ret;
 }

drivers/gpu/drm/i915/selftests/mock_gem_device.c

@@ -41,11 +41,10 @@ void mock_device_flush(struct drm_i915_private *i915)
 
 	lockdep_assert_held(&i915->drm.struct_mutex);
 
-	for_each_engine(engine, i915, id)
-		mock_engine_flush(engine);
-
-	i915_retire_requests(i915);
-	GEM_BUG_ON(i915->gt.active_requests);
+	do {
+		for_each_engine(engine, i915, id)
+			mock_engine_flush(engine);
+	} while (i915_retire_requests(i915));
 }
 
 static void mock_device_release(struct drm_device *dev)
@@ -110,10 +109,6 @@ static void mock_retire_work_handler(struct work_struct *work)
 
 static void mock_idle_work_handler(struct work_struct *work)
 {
-	struct drm_i915_private *i915 =
-		container_of(work, typeof(*i915), gem.idle_work.work);
-
-	i915->gt.active_engines = 0;
 }
 
 static int pm_domain_resume(struct device *dev)
@@ -185,6 +180,8 @@ struct drm_i915_private *mock_gem_device(void)
 
 	mock_uncore_init(&i915->uncore);
 	i915_gem_init__mm(i915);
+	intel_gt_pm_init(i915);
+	atomic_inc(&i915->gt.wakeref.count); /* disable; no hw support */
 
 	init_waitqueue_head(&i915->gpu_error.wait_queue);
 	init_waitqueue_head(&i915->gpu_error.reset_queue);