[Intel-gfx] [PATCH] drm/i915: Replace hangcheck by heartbeats

Chris Wilson chris at chris-wilson.co.uk
Thu Jul 25 23:16:51 UTC 2019


Replace sampling the engine state every so often with a periodic
heartbeat request to measure the health of an engine. This is coupled
with the forced-preemption to allow long running requests to survive so
long as they do not block other users.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
Cc: Jon Bloomfield <jon.bloomfield at intel.com>
---
Note, strictly this still requires struct_mutex-free retirement for the
corner case where the idle-worker is ineffective and we get a backlog of
requests on the kernel ring. Or if the legacy ringbuffer is full...
When we are able to retire from outside of struct_mutex we can do the
full idle-barrier and idle-work from here.
---
 drivers/gpu/drm/i915/Kconfig.profile          |  11 +
 drivers/gpu/drm/i915/Makefile                 |   2 +-
 drivers/gpu/drm/i915/gem/i915_gem_pm.c        |   2 -
 drivers/gpu/drm/i915/gt/intel_engine.h        |  32 --
 drivers/gpu/drm/i915/gt/intel_engine_cs.c     |  10 +-
 .../gpu/drm/i915/gt/intel_engine_heartbeat.c  |  99 +++++
 .../gpu/drm/i915/gt/intel_engine_heartbeat.h  |  17 +
 drivers/gpu/drm/i915/gt/intel_engine_pm.c     |   5 +-
 drivers/gpu/drm/i915/gt/intel_engine_types.h  |  14 +-
 drivers/gpu/drm/i915/gt/intel_gt.c            |   1 -
 drivers/gpu/drm/i915/gt/intel_gt.h            |   4 -
 drivers/gpu/drm/i915/gt/intel_gt_pm.c         |   2 -
 drivers/gpu/drm/i915/gt/intel_gt_types.h      |   9 -
 drivers/gpu/drm/i915/gt/intel_hangcheck.c     | 360 ------------------
 drivers/gpu/drm/i915/gt/intel_reset.c         |   3 +-
 drivers/gpu/drm/i915/gt/selftest_hangcheck.c  |   4 -
 drivers/gpu/drm/i915/i915_debugfs.c           |  86 -----
 drivers/gpu/drm/i915/i915_drv.c               |   6 +-
 drivers/gpu/drm/i915/i915_drv.h               |   1 -
 drivers/gpu/drm/i915/i915_gpu_error.c         |  37 +-
 drivers/gpu/drm/i915/i915_gpu_error.h         |   2 -
 drivers/gpu/drm/i915/i915_params.c            |   5 -
 drivers/gpu/drm/i915/i915_params.h            |   1 -
 23 files changed, 151 insertions(+), 562 deletions(-)
 create mode 100644 drivers/gpu/drm/i915/gt/intel_engine_heartbeat.c
 create mode 100644 drivers/gpu/drm/i915/gt/intel_engine_heartbeat.h
 delete mode 100644 drivers/gpu/drm/i915/gt/intel_hangcheck.c

diff --git a/drivers/gpu/drm/i915/Kconfig.profile b/drivers/gpu/drm/i915/Kconfig.profile
index 3184e8491333..aafb57f84169 100644
--- a/drivers/gpu/drm/i915/Kconfig.profile
+++ b/drivers/gpu/drm/i915/Kconfig.profile
@@ -37,3 +37,14 @@ config DRM_I915_PREEMPT_TIMEOUT
 	  to execute.
 
 	  May be 0 to disable the timeout.
+
+config DRM_I915_HEARTBEAT_INTERVAL
+	int "Interval between heartbeat pulses (ms)"
+	default 2500 # microseconds
+	help
+	  While active the driver uses a periodic request, a heartbeat, to
+	  check the wellness of the GPU and to regularly flush state changes
+	  (idle barriers).
+
+	  May be 0 to disable heartbeats and therefore disable automatic GPU
+	  hang detection.
diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index 524516251a40..18201852d68d 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -73,10 +73,10 @@ gt-y += \
 	gt/intel_breadcrumbs.o \
 	gt/intel_context.o \
 	gt/intel_engine_cs.o \
+	gt/intel_engine_heartbeat.o \
 	gt/intel_engine_pm.o \
 	gt/intel_gt.o \
 	gt/intel_gt_pm.o \
-	gt/intel_hangcheck.o \
 	gt/intel_lrc.o \
 	gt/intel_renderstate.o \
 	gt/intel_reset.o \
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_pm.c b/drivers/gpu/drm/i915/gem/i915_gem_pm.c
index b5561cbdc5ea..a5a0aefcc04c 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_pm.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_pm.c
@@ -170,8 +170,6 @@ void i915_gem_suspend(struct drm_i915_private *i915)
 	GEM_BUG_ON(i915->gt.awake);
 	flush_work(&i915->gem.idle_work);
 
-	cancel_delayed_work_sync(&i915->gt.hangcheck.work);
-
 	i915_gem_drain_freed_objects(i915);
 
 	intel_uc_suspend(&i915->gt.uc);
diff --git a/drivers/gpu/drm/i915/gt/intel_engine.h b/drivers/gpu/drm/i915/gt/intel_engine.h
index db5c73ce86ee..38eeb4320c97 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine.h
+++ b/drivers/gpu/drm/i915/gt/intel_engine.h
@@ -90,38 +90,6 @@ struct drm_printer;
 /* seqno size is actually only a uint32, but since we plan to use MI_FLUSH_DW to
  * do the writes, and that must have qw aligned offsets, simply pretend it's 8b.
  */
-enum intel_engine_hangcheck_action {
-	ENGINE_IDLE = 0,
-	ENGINE_WAIT,
-	ENGINE_ACTIVE_SEQNO,
-	ENGINE_ACTIVE_HEAD,
-	ENGINE_ACTIVE_SUBUNITS,
-	ENGINE_WAIT_KICK,
-	ENGINE_DEAD,
-};
-
-static inline const char *
-hangcheck_action_to_str(const enum intel_engine_hangcheck_action a)
-{
-	switch (a) {
-	case ENGINE_IDLE:
-		return "idle";
-	case ENGINE_WAIT:
-		return "wait";
-	case ENGINE_ACTIVE_SEQNO:
-		return "active seqno";
-	case ENGINE_ACTIVE_HEAD:
-		return "active head";
-	case ENGINE_ACTIVE_SUBUNITS:
-		return "active subunits";
-	case ENGINE_WAIT_KICK:
-		return "wait kick";
-	case ENGINE_DEAD:
-		return "dead";
-	}
-
-	return "unknown";
-}
 
 void intel_engines_set_scheduler_caps(struct drm_i915_private *i915);
 
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_cs.c b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
index 65cbf1d9118d..89f4a3825b77 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_cs.c
+++ b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
@@ -621,7 +621,6 @@ static int intel_engine_setup_common(struct intel_engine_cs *engine)
 	intel_engine_init_active(engine, ENGINE_PHYSICAL);
 	intel_engine_init_breadcrumbs(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);
@@ -1453,8 +1452,13 @@ void intel_engine_dump(struct intel_engine_cs *engine,
 		drm_printf(m, "*** WEDGED ***\n");
 
 	drm_printf(m, "\tAwake? %d\n", atomic_read(&engine->wakeref.count));
-	drm_printf(m, "\tHangcheck: %d ms ago\n",
-		   jiffies_to_msecs(jiffies - engine->hangcheck.action_timestamp));
+
+	rcu_read_lock();
+	rq = READ_ONCE(engine->last_heartbeat);
+	if (rq)
+		drm_printf(m, "\tHeartbeat: %d ms ago\n",
+			   jiffies_to_msecs(jiffies - rq->emitted_jiffies));
+	rcu_read_unlock();
 	drm_printf(m, "\tReset count: %d (global %d)\n",
 		   i915_reset_engine_count(error, engine),
 		   i915_reset_count(error));
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.c b/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.c
new file mode 100644
index 000000000000..42330b1074e6
--- /dev/null
+++ b/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.c
@@ -0,0 +1,99 @@
+/*
+ * SPDX-License-Identifier: MIT
+ *
+ * Copyright © 2019 Intel Corporation
+ */
+
+#include "i915_request.h"
+
+#include "intel_context.h"
+#include "intel_engine_heartbeat.h"
+#include "intel_engine_pm.h"
+#include "intel_gt.h"
+#include "intel_reset.h"
+
+static long delay(void)
+{
+	const long t = msecs_to_jiffies(CONFIG_DRM_I915_HEARTBEAT_INTERVAL);
+
+	return round_jiffies_up_relative(t);
+}
+
+static void heartbeat(struct work_struct *wrk)
+{
+	struct intel_engine_cs *engine =
+		container_of(wrk, typeof(*engine), heartbeat.work);
+	struct intel_context *ce = engine->kernel_context;
+	struct i915_request *rq;
+
+	if (!intel_engine_pm_get_if_awake(engine))
+		return;
+
+	rq = engine->last_heartbeat;
+	if (rq && i915_request_completed(rq)) {
+		i915_request_put(rq);
+		engine->last_heartbeat = NULL;
+	}
+
+	if (intel_gt_is_wedged(engine->gt))
+		goto out;
+
+	if (engine->last_heartbeat) {
+		if (engine->schedule && rq->sched.attr.priority < INT_MAX) {
+			struct i915_sched_attr attr = { .priority = INT_MAX };
+
+			local_bh_disable();
+			engine->schedule(rq, &attr);
+			local_bh_enable();
+		} else {
+			intel_gt_handle_error(engine->gt, engine->mask,
+					      I915_ERROR_CAPTURE,
+					      "stopped heartbeat on %s",
+					      engine->name);
+		}
+		goto out;
+	}
+
+	if (engine->wakeref_serial == engine->serial)
+		goto out;
+
+	if (intel_context_timeline_lock(ce))
+		goto out;
+
+	intel_context_enter(ce);
+	rq = __i915_request_create(ce, GFP_NOWAIT | __GFP_NOWARN);
+	intel_context_exit(ce);
+	if (IS_ERR(rq))
+		goto unlock;
+
+	engine->last_heartbeat = i915_request_get(rq);
+	engine->wakeref_serial = engine->serial + 1;
+
+	i915_request_add_barriers(rq);
+	__i915_request_commit(rq);
+
+unlock:
+	intel_context_timeline_unlock(ce);
+out:
+	schedule_delayed_work(&engine->heartbeat, delay());
+	intel_engine_pm_put(engine);
+}
+
+void intel_engine_unpark_heartbeat(struct intel_engine_cs *engine)
+{
+	if (!CONFIG_DRM_I915_HEARTBEAT_INTERVAL)
+		return;
+
+	schedule_delayed_work(&engine->heartbeat, delay());
+}
+
+void intel_engine_park_heartbeat(struct intel_engine_cs *engine)
+{
+	cancel_delayed_work_sync(&engine->heartbeat);
+	i915_request_put(fetch_and_zero(&engine->last_heartbeat));
+}
+
+void intel_engine_init_heartbeat(struct intel_engine_cs *engine)
+{
+	INIT_DELAYED_WORK(&engine->heartbeat, heartbeat);
+}
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.h b/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.h
new file mode 100644
index 000000000000..e04f9c7aa85d
--- /dev/null
+++ b/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.h
@@ -0,0 +1,17 @@
+/*
+ * SPDX-License-Identifier: MIT
+ *
+ * Copyright © 2019 Intel Corporation
+ */
+
+#ifndef INTEL_ENGINE_HEARTBEAT_H
+#define INTEL_ENGINE_HEARTBEAT_H
+
+struct intel_engine_cs;
+
+void intel_engine_init_heartbeat(struct intel_engine_cs *engine);
+
+void intel_engine_park_heartbeat(struct intel_engine_cs *engine);
+void intel_engine_unpark_heartbeat(struct intel_engine_cs *engine);
+
+#endif /* INTEL_ENGINE_HEARTBEAT_H */
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_pm.c b/drivers/gpu/drm/i915/gt/intel_engine_pm.c
index e74fbf04a68d..6349bb038c72 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_pm.c
+++ b/drivers/gpu/drm/i915/gt/intel_engine_pm.c
@@ -7,6 +7,7 @@
 #include "i915_drv.h"
 
 #include "intel_engine.h"
+#include "intel_engine_heartbeat.h"
 #include "intel_engine_pm.h"
 #include "intel_gt.h"
 #include "intel_gt_pm.h"
@@ -32,7 +33,7 @@ static int __engine_unpark(struct intel_wakeref *wf)
 	if (engine->unpark)
 		engine->unpark(engine);
 
-	intel_engine_init_hangcheck(engine);
+	intel_engine_unpark_heartbeat(engine);
 	return 0;
 }
 
@@ -115,6 +116,7 @@ static int __engine_park(struct intel_wakeref *wf)
 
 	GEM_TRACE("%s\n", engine->name);
 
+	intel_engine_park_heartbeat(engine);
 	intel_engine_disarm_breadcrumbs(engine);
 
 	/* Must be reset upon idling, or we may miss the busy wakeup. */
@@ -142,4 +144,5 @@ void intel_engine_pm_put(struct intel_engine_cs *engine)
 void intel_engine_init__pm(struct intel_engine_cs *engine)
 {
 	intel_wakeref_init(&engine->wakeref);
+	intel_engine_init_heartbeat(engine);
 }
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_types.h b/drivers/gpu/drm/i915/gt/intel_engine_types.h
index 8be63019d707..9a3ead556743 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_types.h
+++ b/drivers/gpu/drm/i915/gt/intel_engine_types.h
@@ -14,6 +14,7 @@
 #include <linux/llist.h>
 #include <linux/timer.h>
 #include <linux/types.h>
+#include <linux/workqueue.h>
 
 #include "i915_gem.h"
 #include "i915_gem_batch_pool.h"
@@ -55,14 +56,6 @@ struct intel_instdone {
 	u32 row[I915_MAX_SLICES][I915_MAX_SUBSLICES];
 };
 
-struct intel_engine_hangcheck {
-	u64 acthd;
-	u32 last_ring;
-	u32 last_head;
-	unsigned long action_timestamp;
-	struct intel_instdone instdone;
-};
-
 struct intel_ring {
 	struct kref ref;
 	struct i915_vma *vma;
@@ -298,6 +291,9 @@ struct intel_engine_cs {
 	struct drm_i915_gem_object *default_state;
 	void *pinned_default_state;
 
+	struct delayed_work heartbeat;
+	struct i915_request *last_heartbeat;
+
 	/* Rather than have every client wait upon all user interrupts,
 	 * with the herd waking after every interrupt and each doing the
 	 * heavyweight seqno dance, we delegate the task (of being the
@@ -437,8 +433,6 @@ struct intel_engine_cs {
 	/* status_notifier: list of callbacks for context-switch changes */
 	struct atomic_notifier_head context_status_notifier;
 
-	struct intel_engine_hangcheck hangcheck;
-
 #define I915_ENGINE_NEEDS_CMD_PARSER BIT(0)
 #define I915_ENGINE_SUPPORTS_STATS   BIT(1)
 #define I915_ENGINE_HAS_PREEMPTION   BIT(2)
diff --git a/drivers/gpu/drm/i915/gt/intel_gt.c b/drivers/gpu/drm/i915/gt/intel_gt.c
index f7e69db4019d..feaf916c9abd 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt.c
+++ b/drivers/gpu/drm/i915/gt/intel_gt.c
@@ -19,7 +19,6 @@ void intel_gt_init_early(struct intel_gt *gt, struct drm_i915_private *i915)
 
 	spin_lock_init(&gt->closed_lock);
 
-	intel_gt_init_hangcheck(gt);
 	intel_gt_init_reset(gt);
 	intel_gt_pm_init_early(gt);
 }
diff --git a/drivers/gpu/drm/i915/gt/intel_gt.h b/drivers/gpu/drm/i915/gt/intel_gt.h
index 640bb0531f5b..54d22913ede3 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt.h
+++ b/drivers/gpu/drm/i915/gt/intel_gt.h
@@ -39,8 +39,6 @@ void intel_gt_clear_error_registers(struct intel_gt *gt,
 void intel_gt_flush_ggtt_writes(struct intel_gt *gt);
 void intel_gt_chipset_flush(struct intel_gt *gt);
 
-void intel_gt_init_hangcheck(struct intel_gt *gt);
-
 int intel_gt_init_scratch(struct intel_gt *gt, unsigned int size);
 void intel_gt_fini_scratch(struct intel_gt *gt);
 
@@ -55,6 +53,4 @@ static inline bool intel_gt_is_wedged(struct intel_gt *gt)
 	return __intel_reset_failed(&gt->reset);
 }
 
-void intel_gt_queue_hangcheck(struct intel_gt *gt);
-
 #endif /* __INTEL_GT_H__ */
diff --git a/drivers/gpu/drm/i915/gt/intel_gt_pm.c b/drivers/gpu/drm/i915/gt/intel_gt_pm.c
index 65c0d0c9d543..d223b07ee324 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt_pm.c
+++ b/drivers/gpu/drm/i915/gt/intel_gt_pm.c
@@ -46,8 +46,6 @@ static int intel_gt_unpark(struct intel_wakeref *wf)
 
 	i915_pmu_gt_unparked(i915);
 
-	intel_gt_queue_hangcheck(gt);
-
 	pm_notify(i915, INTEL_GT_UNPARK);
 
 	return 0;
diff --git a/drivers/gpu/drm/i915/gt/intel_gt_types.h b/drivers/gpu/drm/i915/gt/intel_gt_types.h
index 34d4a868e4f1..0112bb98cbf3 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt_types.h
+++ b/drivers/gpu/drm/i915/gt/intel_gt_types.h
@@ -23,14 +23,6 @@ struct drm_i915_private;
 struct i915_ggtt;
 struct intel_uncore;
 
-struct intel_hangcheck {
-	/* For hangcheck timer */
-#define DRM_I915_HANGCHECK_PERIOD 1500 /* in ms */
-#define DRM_I915_HANGCHECK_JIFFIES msecs_to_jiffies(DRM_I915_HANGCHECK_PERIOD)
-
-	struct delayed_work work;
-};
-
 struct intel_gt {
 	struct drm_i915_private *i915;
 	struct intel_uncore *uncore;
@@ -54,7 +46,6 @@ struct intel_gt {
 	struct list_head closed_vma;
 	spinlock_t closed_lock; /* guards the list of closed_vma */
 
-	struct intel_hangcheck hangcheck;
 	struct intel_reset reset;
 
 	/**
diff --git a/drivers/gpu/drm/i915/gt/intel_hangcheck.c b/drivers/gpu/drm/i915/gt/intel_hangcheck.c
deleted file mode 100644
index 05d042cdefe2..000000000000
--- a/drivers/gpu/drm/i915/gt/intel_hangcheck.c
+++ /dev/null
@@ -1,360 +0,0 @@
-/*
- * Copyright © 2016 Intel Corporation
- *
- * Permission is hereby granted, free of charge, to any person obtaining a
- * copy of this software and associated documentation files (the "Software"),
- * to deal in the Software without restriction, including without limitation
- * the rights to use, copy, modify, merge, publish, distribute, sublicense,
- * and/or sell copies of the Software, and to permit persons to whom the
- * Software is furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice (including the next
- * paragraph) shall be included in all copies or substantial portions of the
- * Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
- * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
- * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
- * IN THE SOFTWARE.
- *
- */
-
-#include "i915_drv.h"
-#include "intel_engine.h"
-#include "intel_gt.h"
-#include "intel_reset.h"
-
-struct hangcheck {
-	u64 acthd;
-	u32 ring;
-	u32 head;
-	enum intel_engine_hangcheck_action action;
-	unsigned long action_timestamp;
-	int deadlock;
-	struct intel_instdone instdone;
-	bool wedged:1;
-	bool stalled:1;
-};
-
-static bool instdone_unchanged(u32 current_instdone, u32 *old_instdone)
-{
-	u32 tmp = current_instdone | *old_instdone;
-	bool unchanged;
-
-	unchanged = tmp == *old_instdone;
-	*old_instdone |= tmp;
-
-	return unchanged;
-}
-
-static bool subunits_stuck(struct intel_engine_cs *engine)
-{
-	struct drm_i915_private *dev_priv = engine->i915;
-	struct intel_instdone instdone;
-	struct intel_instdone *accu_instdone = &engine->hangcheck.instdone;
-	bool stuck;
-	int slice;
-	int subslice;
-
-	intel_engine_get_instdone(engine, &instdone);
-
-	/* There might be unstable subunit states even when
-	 * actual head is not moving. Filter out the unstable ones by
-	 * accumulating the undone -> done transitions and only
-	 * consider those as progress.
-	 */
-	stuck = instdone_unchanged(instdone.instdone,
-				   &accu_instdone->instdone);
-	stuck &= instdone_unchanged(instdone.slice_common,
-				    &accu_instdone->slice_common);
-
-	for_each_instdone_slice_subslice(dev_priv, slice, subslice) {
-		stuck &= instdone_unchanged(instdone.sampler[slice][subslice],
-					    &accu_instdone->sampler[slice][subslice]);
-		stuck &= instdone_unchanged(instdone.row[slice][subslice],
-					    &accu_instdone->row[slice][subslice]);
-	}
-
-	return stuck;
-}
-
-static enum intel_engine_hangcheck_action
-head_stuck(struct intel_engine_cs *engine, u64 acthd)
-{
-	if (acthd != engine->hangcheck.acthd) {
-
-		/* Clear subunit states on head movement */
-		memset(&engine->hangcheck.instdone, 0,
-		       sizeof(engine->hangcheck.instdone));
-
-		return ENGINE_ACTIVE_HEAD;
-	}
-
-	if (!subunits_stuck(engine))
-		return ENGINE_ACTIVE_SUBUNITS;
-
-	return ENGINE_DEAD;
-}
-
-static enum intel_engine_hangcheck_action
-engine_stuck(struct intel_engine_cs *engine, u64 acthd)
-{
-	enum intel_engine_hangcheck_action ha;
-	u32 tmp;
-
-	ha = head_stuck(engine, acthd);
-	if (ha != ENGINE_DEAD)
-		return ha;
-
-	if (IS_GEN(engine->i915, 2))
-		return ENGINE_DEAD;
-
-	/* Is the chip hanging on a WAIT_FOR_EVENT?
-	 * If so we can simply poke the RB_WAIT bit
-	 * and break the hang. This should work on
-	 * all but the second generation chipsets.
-	 */
-	tmp = ENGINE_READ(engine, RING_CTL);
-	if (tmp & RING_WAIT) {
-		intel_gt_handle_error(engine->gt, engine->mask, 0,
-				      "stuck wait on %s", engine->name);
-		ENGINE_WRITE(engine, RING_CTL, tmp);
-		return ENGINE_WAIT_KICK;
-	}
-
-	return ENGINE_DEAD;
-}
-
-static void hangcheck_load_sample(struct intel_engine_cs *engine,
-				  struct hangcheck *hc)
-{
-	hc->acthd = intel_engine_get_active_head(engine);
-	hc->ring = ENGINE_READ(engine, RING_START);
-	hc->head = ENGINE_READ(engine, RING_HEAD);
-}
-
-static void hangcheck_store_sample(struct intel_engine_cs *engine,
-				   const struct hangcheck *hc)
-{
-	engine->hangcheck.acthd = hc->acthd;
-	engine->hangcheck.last_ring = hc->ring;
-	engine->hangcheck.last_head = hc->head;
-}
-
-static enum intel_engine_hangcheck_action
-hangcheck_get_action(struct intel_engine_cs *engine,
-		     const struct hangcheck *hc)
-{
-	if (intel_engine_is_idle(engine))
-		return ENGINE_IDLE;
-
-	if (engine->hangcheck.last_ring != hc->ring)
-		return ENGINE_ACTIVE_SEQNO;
-
-	if (engine->hangcheck.last_head != hc->head)
-		return ENGINE_ACTIVE_SEQNO;
-
-	return engine_stuck(engine, hc->acthd);
-}
-
-static void hangcheck_accumulate_sample(struct intel_engine_cs *engine,
-					struct hangcheck *hc)
-{
-	unsigned long timeout = I915_ENGINE_DEAD_TIMEOUT;
-
-	hc->action = hangcheck_get_action(engine, hc);
-
-	/* We always increment the progress
-	 * if the engine is busy and still processing
-	 * the same request, so that no single request
-	 * can run indefinitely (such as a chain of
-	 * batches). The only time we do not increment
-	 * the hangcheck score on this ring, if this
-	 * engine is in a legitimate wait for another
-	 * engine. In that case the waiting engine is a
-	 * victim and we want to be sure we catch the
-	 * right culprit. Then every time we do kick
-	 * the ring, make it as a progress as the seqno
-	 * advancement might ensure and if not, it
-	 * will catch the hanging engine.
-	 */
-
-	switch (hc->action) {
-	case ENGINE_IDLE:
-	case ENGINE_ACTIVE_SEQNO:
-		/* Clear head and subunit states on seqno movement */
-		hc->acthd = 0;
-
-		memset(&engine->hangcheck.instdone, 0,
-		       sizeof(engine->hangcheck.instdone));
-
-		/* Intentional fall through */
-	case ENGINE_WAIT_KICK:
-	case ENGINE_WAIT:
-		engine->hangcheck.action_timestamp = jiffies;
-		break;
-
-	case ENGINE_ACTIVE_HEAD:
-	case ENGINE_ACTIVE_SUBUNITS:
-		/*
-		 * Seqno stuck with still active engine gets leeway,
-		 * in hopes that it is just a long shader.
-		 */
-		timeout = I915_SEQNO_DEAD_TIMEOUT;
-		break;
-
-	case ENGINE_DEAD:
-		break;
-
-	default:
-		MISSING_CASE(hc->action);
-	}
-
-	hc->stalled = time_after(jiffies,
-				 engine->hangcheck.action_timestamp + timeout);
-	hc->wedged = time_after(jiffies,
-				 engine->hangcheck.action_timestamp +
-				 I915_ENGINE_WEDGED_TIMEOUT);
-}
-
-static void hangcheck_declare_hang(struct intel_gt *gt,
-				   intel_engine_mask_t hung,
-				   intel_engine_mask_t stuck)
-{
-	struct intel_engine_cs *engine;
-	intel_engine_mask_t tmp;
-	char msg[80];
-	int len;
-
-	/* If some rings hung but others were still busy, only
-	 * blame the hanging rings in the synopsis.
-	 */
-	if (stuck != hung)
-		hung &= ~stuck;
-	len = scnprintf(msg, sizeof(msg),
-			"%s on ", stuck == hung ? "no progress" : "hang");
-	for_each_engine_masked(engine, gt->i915, hung, tmp)
-		len += scnprintf(msg + len, sizeof(msg) - len,
-				 "%s, ", engine->name);
-	msg[len-2] = '\0';
-
-	return intel_gt_handle_error(gt, hung, I915_ERROR_CAPTURE, "%s", msg);
-}
-
-/*
- * This is called when the chip hasn't reported back with completed
- * batchbuffers in a long time. We keep track per ring seqno progress and
- * if there are no progress, hangcheck score for that ring is increased.
- * Further, acthd is inspected to see if the ring is stuck. On stuck case
- * we kick the ring. If we see no progress on three subsequent calls
- * we assume chip is wedged and try to fix it by resetting the chip.
- */
-static void hangcheck_elapsed(struct work_struct *work)
-{
-	struct intel_gt *gt =
-		container_of(work, typeof(*gt), hangcheck.work.work);
-	intel_engine_mask_t hung = 0, stuck = 0, wedged = 0;
-	struct intel_engine_cs *engine;
-	enum intel_engine_id id;
-	intel_wakeref_t wakeref;
-
-	if (!i915_modparams.enable_hangcheck)
-		return;
-
-	if (!READ_ONCE(gt->awake))
-		return;
-
-	if (intel_gt_is_wedged(gt))
-		return;
-
-	wakeref = intel_runtime_pm_get_if_in_use(&gt->i915->runtime_pm);
-	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.
-	 */
-	intel_uncore_arm_unclaimed_mmio_detection(gt->uncore);
-
-	for_each_engine(engine, gt->i915, id) {
-		struct hangcheck hc;
-
-		intel_engine_signal_breadcrumbs(engine);
-
-		hangcheck_load_sample(engine, &hc);
-		hangcheck_accumulate_sample(engine, &hc);
-		hangcheck_store_sample(engine, &hc);
-
-		if (hc.stalled) {
-			hung |= engine->mask;
-			if (hc.action != ENGINE_DEAD)
-				stuck |= engine->mask;
-		}
-
-		if (hc.wedged)
-			wedged |= engine->mask;
-	}
-
-	if (GEM_SHOW_DEBUG() && (hung | stuck)) {
-		struct drm_printer p = drm_debug_printer("hangcheck");
-
-		for_each_engine(engine, gt->i915, id) {
-			if (intel_engine_is_idle(engine))
-				continue;
-
-			intel_engine_dump(engine, &p, "%s\n", engine->name);
-		}
-	}
-
-	if (wedged) {
-		dev_err(gt->i915->drm.dev,
-			"GPU recovery timed out,"
-			" cancelling all in-flight rendering.\n");
-		GEM_TRACE_DUMP();
-		intel_gt_set_wedged(gt);
-	}
-
-	if (hung)
-		hangcheck_declare_hang(gt, hung, stuck);
-
-	intel_runtime_pm_put(&gt->i915->runtime_pm, wakeref);
-
-	/* Reset timer in case GPU hangs without another request being added */
-	intel_gt_queue_hangcheck(gt);
-}
-
-void intel_gt_queue_hangcheck(struct intel_gt *gt)
-{
-	unsigned long delay;
-
-	if (unlikely(!i915_modparams.enable_hangcheck))
-		return;
-
-	/*
-	 * Don't continually defer the hangcheck so that it is always run at
-	 * least once after work has been scheduled on any ring. Otherwise,
-	 * we will ignore a hung ring if a second ring is kept busy.
-	 */
-
-	delay = round_jiffies_up_relative(DRM_I915_HANGCHECK_JIFFIES);
-	queue_delayed_work(system_long_wq, &gt->hangcheck.work, delay);
-}
-
-void intel_engine_init_hangcheck(struct intel_engine_cs *engine)
-{
-	memset(&engine->hangcheck, 0, sizeof(engine->hangcheck));
-	engine->hangcheck.action_timestamp = jiffies;
-}
-
-void intel_gt_init_hangcheck(struct intel_gt *gt)
-{
-	INIT_DELAYED_WORK(&gt->hangcheck.work, hangcheck_elapsed);
-}
-
-#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
-#include "selftest_hangcheck.c"
-#endif
diff --git a/drivers/gpu/drm/i915/gt/intel_reset.c b/drivers/gpu/drm/i915/gt/intel_reset.c
index 98c071fe532b..0cb457538e62 100644
--- a/drivers/gpu/drm/i915/gt/intel_reset.c
+++ b/drivers/gpu/drm/i915/gt/intel_reset.c
@@ -978,8 +978,6 @@ void intel_gt_reset(struct intel_gt *gt,
 	if (ret)
 		goto taint;
 
-	intel_gt_queue_hangcheck(gt);
-
 finish:
 	reset_finish(gt, awake);
 unlock:
@@ -1305,4 +1303,5 @@ void __intel_fini_wedge(struct intel_wedge_me *w)
 
 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
 #include "selftest_reset.c"
+#include "selftest_hangcheck.c"
 #endif
diff --git a/drivers/gpu/drm/i915/gt/selftest_hangcheck.c b/drivers/gpu/drm/i915/gt/selftest_hangcheck.c
index e2fa38a1ff0f..9d64390966e3 100644
--- a/drivers/gpu/drm/i915/gt/selftest_hangcheck.c
+++ b/drivers/gpu/drm/i915/gt/selftest_hangcheck.c
@@ -1732,7 +1732,6 @@ int intel_hangcheck_live_selftests(struct drm_i915_private *i915)
 	};
 	struct intel_gt *gt = &i915->gt;
 	intel_wakeref_t wakeref;
-	bool saved_hangcheck;
 	int err;
 
 	if (!intel_has_gpu_reset(gt->i915))
@@ -1742,8 +1741,6 @@ int intel_hangcheck_live_selftests(struct drm_i915_private *i915)
 		return -EIO; /* we're long past hope of a successful reset */
 
 	wakeref = intel_runtime_pm_get(&gt->i915->runtime_pm);
-	saved_hangcheck = fetch_and_zero(&i915_modparams.enable_hangcheck);
-	drain_delayed_work(&gt->hangcheck.work); /* flush param */
 
 	err = intel_gt_live_subtests(tests, gt);
 
@@ -1751,7 +1748,6 @@ int intel_hangcheck_live_selftests(struct drm_i915_private *i915)
 	igt_flush_test(gt->i915, I915_WAIT_LOCKED);
 	mutex_unlock(&gt->i915->drm.struct_mutex);
 
-	i915_modparams.enable_hangcheck = saved_hangcheck;
 	intel_runtime_pm_put(&gt->i915->runtime_pm, wakeref);
 
 	return err;
diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 24787bb48c9f..1f0408ff345b 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -1044,91 +1044,6 @@ static int i915_frequency_info(struct seq_file *m, void *unused)
 	return ret;
 }
 
-static void i915_instdone_info(struct drm_i915_private *dev_priv,
-			       struct seq_file *m,
-			       struct intel_instdone *instdone)
-{
-	int slice;
-	int subslice;
-
-	seq_printf(m, "\t\tINSTDONE: 0x%08x\n",
-		   instdone->instdone);
-
-	if (INTEL_GEN(dev_priv) <= 3)
-		return;
-
-	seq_printf(m, "\t\tSC_INSTDONE: 0x%08x\n",
-		   instdone->slice_common);
-
-	if (INTEL_GEN(dev_priv) <= 6)
-		return;
-
-	for_each_instdone_slice_subslice(dev_priv, slice, subslice)
-		seq_printf(m, "\t\tSAMPLER_INSTDONE[%d][%d]: 0x%08x\n",
-			   slice, subslice, instdone->sampler[slice][subslice]);
-
-	for_each_instdone_slice_subslice(dev_priv, slice, subslice)
-		seq_printf(m, "\t\tROW_INSTDONE[%d][%d]: 0x%08x\n",
-			   slice, subslice, instdone->row[slice][subslice]);
-}
-
-static int i915_hangcheck_info(struct seq_file *m, void *unused)
-{
-	struct drm_i915_private *i915 = node_to_i915(m->private);
-	struct intel_gt *gt = &i915->gt;
-	struct intel_engine_cs *engine;
-	intel_wakeref_t wakeref;
-	enum intel_engine_id id;
-
-	seq_printf(m, "Reset flags: %lx\n", gt->reset.flags);
-	if (test_bit(I915_WEDGED, &gt->reset.flags))
-		seq_puts(m, "\tWedged\n");
-	if (test_bit(I915_RESET_BACKOFF, &gt->reset.flags))
-		seq_puts(m, "\tDevice (global) reset in progress\n");
-
-	if (!i915_modparams.enable_hangcheck) {
-		seq_puts(m, "Hangcheck disabled\n");
-		return 0;
-	}
-
-	if (timer_pending(&gt->hangcheck.work.timer))
-		seq_printf(m, "Hangcheck active, timer fires in %dms\n",
-			   jiffies_to_msecs(gt->hangcheck.work.timer.expires -
-					    jiffies));
-	else if (delayed_work_pending(&gt->hangcheck.work))
-		seq_puts(m, "Hangcheck active, work pending\n");
-	else
-		seq_puts(m, "Hangcheck inactive\n");
-
-	seq_printf(m, "GT active? %s\n", yesno(gt->awake));
-
-	with_intel_runtime_pm(&i915->runtime_pm, wakeref) {
-		for_each_engine(engine, i915, id) {
-			struct intel_instdone instdone;
-
-			seq_printf(m, "%s: %d ms ago\n",
-				   engine->name,
-				   jiffies_to_msecs(jiffies -
-						    engine->hangcheck.action_timestamp));
-
-			seq_printf(m, "\tACTHD = 0x%08llx [current 0x%08llx]\n",
-				   (long long)engine->hangcheck.acthd,
-				   intel_engine_get_active_head(engine));
-
-			intel_engine_get_instdone(engine, &instdone);
-
-			seq_puts(m, "\tinstdone read =\n");
-			i915_instdone_info(i915, m, &instdone);
-
-			seq_puts(m, "\tinstdone accu =\n");
-			i915_instdone_info(i915, m,
-					   &engine->hangcheck.instdone);
-		}
-	}
-
-	return 0;
-}
-
 static int ironlake_drpc_info(struct seq_file *m)
 {
 	struct drm_i915_private *i915 = node_to_i915(m->private);
@@ -4387,7 +4302,6 @@ static const struct drm_info_list i915_debugfs_list[] = {
 	{"i915_guc_stage_pool", i915_guc_stage_pool, 0},
 	{"i915_huc_load_status", i915_huc_load_status_info, 0},
 	{"i915_frequency_info", i915_frequency_info, 0},
-	{"i915_hangcheck_info", i915_hangcheck_info, 0},
 	{"i915_drpc_info", i915_drpc_info, 0},
 	{"i915_emon_status", i915_emon_status, 0},
 	{"i915_ring_freq_table", i915_ring_freq_table, 0},
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index f2d3d754af37..8c277fbf9663 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -411,8 +411,7 @@ static int i915_getparam_ioctl(struct drm_device *dev, void *data,
 			return -ENODEV;
 		break;
 	case I915_PARAM_HAS_GPU_RESET:
-		value = i915_modparams.enable_hangcheck &&
-			intel_has_gpu_reset(dev_priv);
+		value = intel_has_gpu_reset(dev_priv);
 		if (value && intel_has_reset_engine(dev_priv))
 			value = 2;
 		break;
@@ -1975,10 +1974,7 @@ void i915_driver_remove(struct drm_device *dev)
 
 	intel_csr_ucode_fini(dev_priv);
 
-	/* Free error state after interrupts are fully disabled. */
-	cancel_delayed_work_sync(&dev_priv->gt.hangcheck.work);
 	i915_reset_error_state(dev_priv);
-
 	i915_gem_driver_remove(dev_priv);
 
 	intel_power_domains_driver_remove(dev_priv);
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 59d4a1146039..0e715b1266f0 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2375,7 +2375,6 @@ extern const struct dev_pm_ops i915_pm_ops;
 int i915_driver_probe(struct pci_dev *pdev, const struct pci_device_id *ent);
 void i915_driver_remove(struct drm_device *dev);
 
-void intel_engine_init_hangcheck(struct intel_engine_cs *engine);
 int vlv_force_gfx_clock(struct drm_i915_private *dev_priv, bool on);
 
 static inline bool intel_gvt_active(struct drm_i915_private *dev_priv)
diff --git a/drivers/gpu/drm/i915/i915_gpu_error.c b/drivers/gpu/drm/i915/i915_gpu_error.c
index 674d341a23f6..eff10ca5a788 100644
--- a/drivers/gpu/drm/i915/i915_gpu_error.c
+++ b/drivers/gpu/drm/i915/i915_gpu_error.c
@@ -554,10 +554,6 @@ static void error_print_engine(struct drm_i915_error_state_buf *m,
 	}
 	err_printf(m, "  ring->head: 0x%08x\n", ee->cpu_ring_head);
 	err_printf(m, "  ring->tail: 0x%08x\n", ee->cpu_ring_tail);
-	err_printf(m, "  hangcheck timestamp: %dms (%lu%s)\n",
-		   jiffies_to_msecs(ee->hangcheck_timestamp - epoch),
-		   ee->hangcheck_timestamp,
-		   ee->hangcheck_timestamp == epoch ? "; epoch" : "");
 	err_printf(m, "  engine reset count: %u\n", ee->reset_count);
 
 	for (n = 0; n < ee->num_ports; n++) {
@@ -695,11 +691,8 @@ static void __err_print_to_sgl(struct drm_i915_error_state_buf *m,
 	ts = ktime_to_timespec64(error->uptime);
 	err_printf(m, "Uptime: %lld s %ld us\n",
 		   (s64)ts.tv_sec, ts.tv_nsec / NSEC_PER_USEC);
-	err_printf(m, "Epoch: %lu jiffies (%u HZ)\n", error->epoch, HZ);
-	err_printf(m, "Capture: %lu jiffies; %d ms ago, %d ms after epoch\n",
-		   error->capture,
-		   jiffies_to_msecs(jiffies - error->capture),
-		   jiffies_to_msecs(error->capture - error->epoch));
+	err_printf(m, "Capture: %lu jiffies; %d ms ago\n",
+		   error->capture, jiffies_to_msecs(jiffies - error->capture));
 
 	for (i = 0; i < ARRAY_SIZE(error->engine); i++) {
 		if (!error->engine[i].context.pid)
@@ -760,7 +753,9 @@ static void __err_print_to_sgl(struct drm_i915_error_state_buf *m,
 
 	for (i = 0; i < ARRAY_SIZE(error->engine); i++) {
 		if (error->engine[i].engine_id != -1)
-			error_print_engine(m, &error->engine[i], error->epoch);
+			error_print_engine(m,
+					   &error->engine[i],
+					   error->capture);
 	}
 
 	for (i = 0; i < ARRAY_SIZE(error->engine); i++) {
@@ -790,7 +785,7 @@ static void __err_print_to_sgl(struct drm_i915_error_state_buf *m,
 			for (j = 0; j < ee->num_requests; j++)
 				error_print_request(m, " ",
 						    &ee->requests[j],
-						    error->epoch);
+						    error->capture);
 		}
 
 		print_error_obj(m, m->i915->engine[i],
@@ -1171,8 +1166,6 @@ static void error_record_engine_registers(struct i915_gpu_state *error,
 	}
 
 	ee->idle = intel_engine_is_idle(engine);
-	if (!ee->idle)
-		ee->hangcheck_timestamp = engine->hangcheck.action_timestamp;
 	ee->reset_count = i915_reset_engine_count(&dev_priv->gpu_error,
 						  engine);
 
@@ -1673,22 +1666,6 @@ static void capture_params(struct i915_gpu_state *error)
 	i915_params_copy(&error->params, &i915_modparams);
 }
 
-static unsigned long capture_find_epoch(const struct i915_gpu_state *error)
-{
-	unsigned long epoch = error->capture;
-	int i;
-
-	for (i = 0; i < ARRAY_SIZE(error->engine); i++) {
-		const struct drm_i915_error_engine *ee = &error->engine[i];
-
-		if (ee->hangcheck_timestamp &&
-		    time_before(ee->hangcheck_timestamp, epoch))
-			epoch = ee->hangcheck_timestamp;
-	}
-
-	return epoch;
-}
-
 static void capture_finish(struct i915_gpu_state *error)
 {
 	struct i915_ggtt *ggtt = &error->i915->ggtt;
@@ -1740,8 +1717,6 @@ i915_capture_gpu_state(struct drm_i915_private *i915)
 	error->overlay = intel_overlay_capture_error_state(i915);
 	error->display = intel_display_capture_error_state(i915);
 
-	error->epoch = capture_find_epoch(error);
-
 	capture_finish(error);
 	compress_fini(&compress);
 
diff --git a/drivers/gpu/drm/i915/i915_gpu_error.h b/drivers/gpu/drm/i915/i915_gpu_error.h
index a24c35107d16..c4ba297ca862 100644
--- a/drivers/gpu/drm/i915/i915_gpu_error.h
+++ b/drivers/gpu/drm/i915/i915_gpu_error.h
@@ -34,7 +34,6 @@ struct i915_gpu_state {
 	ktime_t boottime;
 	ktime_t uptime;
 	unsigned long capture;
-	unsigned long epoch;
 
 	struct drm_i915_private *i915;
 
@@ -84,7 +83,6 @@ struct i915_gpu_state {
 		int engine_id;
 		/* Software tracked state */
 		bool idle;
-		unsigned long hangcheck_timestamp;
 		int num_requests;
 		u32 reset_count;
 
diff --git a/drivers/gpu/drm/i915/i915_params.c b/drivers/gpu/drm/i915/i915_params.c
index 296452f9efe4..e4cd58e90e40 100644
--- a/drivers/gpu/drm/i915/i915_params.c
+++ b/drivers/gpu/drm/i915/i915_params.c
@@ -77,11 +77,6 @@ i915_param_named(error_capture, bool, 0600,
 	"triaging and debugging hangs.");
 #endif
 
-i915_param_named_unsafe(enable_hangcheck, bool, 0600,
-	"Periodically check GPU activity for detecting hangs. "
-	"WARNING: Disabling this can cause system wide hangs. "
-	"(default: true)");
-
 i915_param_named_unsafe(enable_psr, int, 0600,
 	"Enable PSR "
 	"(0=disabled, 1=enabled) "
diff --git a/drivers/gpu/drm/i915/i915_params.h b/drivers/gpu/drm/i915/i915_params.h
index d29ade3b7de6..9a3359c6f6f3 100644
--- a/drivers/gpu/drm/i915/i915_params.h
+++ b/drivers/gpu/drm/i915/i915_params.h
@@ -68,7 +68,6 @@ struct drm_printer;
 	param(char *, force_probe, CONFIG_DRM_I915_FORCE_PROBE) \
 	/* leave bools at the end to not create holes */ \
 	param(bool, alpha_support, IS_ENABLED(CONFIG_DRM_I915_ALPHA_SUPPORT)) \
-	param(bool, enable_hangcheck, true) \
 	param(bool, prefault_disable, false) \
 	param(bool, load_detect_test, false) \
 	param(bool, force_reset_modeset_test, false) \
-- 
2.22.0



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