drm/i915: Reset the breadcrumbs IRQ more carefully

Along with the interrupt, we want to restore the fake-irq and
wait-timeout detection. If we use the breadcrumbs interface to setup the
interrupt as it wants, the auxiliary timers will also be restored.

v2: Cancel both timers as well, sanitize the IMR.

Fixes: 821ed7df ("drm/i915: Update reset path to fix incomplete requests")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161007065327.24515-3-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/intel_breadcrumbs.c

@@ -578,6 +578,36 @@ int intel_engine_init_breadcrumbs(struct intel_engine_cs *engine)
 	return 0;
 }
 
+static void cancel_fake_irq(struct intel_engine_cs *engine)
+{
+	struct intel_breadcrumbs *b = &engine->breadcrumbs;
+
+	del_timer_sync(&b->hangcheck);
+	del_timer_sync(&b->fake_irq);
+	clear_bit(engine->id, &engine->i915->gpu_error.missed_irq_rings);
+}
+
+void intel_engine_reset_breadcrumbs(struct intel_engine_cs *engine)
+{
+	struct intel_breadcrumbs *b = &engine->breadcrumbs;
+
+	cancel_fake_irq(engine);
+	spin_lock(&b->lock);
+
+	__intel_breadcrumbs_disable_irq(b);
+	if (intel_engine_has_waiter(engine)) {
+		b->timeout = wait_timeout();
+		__intel_breadcrumbs_enable_irq(b);
+		if (READ_ONCE(b->irq_posted))
+			wake_up_process(b->first_wait->tsk);
+	} else {
+		/* sanitize the IMR and unmask any auxiliary interrupts */
+		irq_disable(engine);
+	}
+
+	spin_unlock(&b->lock);
+}
+
 void intel_engine_fini_breadcrumbs(struct intel_engine_cs *engine)
 {
 	struct intel_breadcrumbs *b = &engine->breadcrumbs;
@@ -585,8 +615,7 @@ void intel_engine_fini_breadcrumbs(struct intel_engine_cs *engine)
 	if (!IS_ERR_OR_NULL(b->signaler))
 		kthread_stop(b->signaler);
 
-	del_timer_sync(&b->hangcheck);
-	del_timer_sync(&b->fake_irq);
+	cancel_fake_irq(engine);
 }
 
 unsigned int intel_kick_waiters(struct drm_i915_private *i915)

drivers/gpu/drm/i915/intel_engine_cs.c

@@ -210,9 +210,6 @@ void intel_engine_init_seqno(struct intel_engine_cs *engine, u32 seqno)
 void intel_engine_init_hangcheck(struct intel_engine_cs *engine)
 {
 	memset(&engine->hangcheck, 0, sizeof(engine->hangcheck));
-	clear_bit(engine->id, &engine->i915->gpu_error.missed_irq_rings);
-	if (intel_engine_has_waiter(engine))
-		i915_queue_hangcheck(engine->i915);
 }
 
 static void intel_engine_init_requests(struct intel_engine_cs *engine)
@@ -307,18 +304,6 @@ int intel_engine_init_common(struct intel_engine_cs *engine)
 	return 0;
 }
 
-void intel_engine_reset_irq(struct intel_engine_cs *engine)
-{
-	struct drm_i915_private *dev_priv = engine->i915;
-
-	spin_lock_irq(&dev_priv->irq_lock);
-	if (intel_engine_has_waiter(engine))
-		engine->irq_enable(engine);
-	else
-		engine->irq_disable(engine);
-	spin_unlock_irq(&dev_priv->irq_lock);
-}
-
 /**
  * intel_engines_cleanup_common - cleans up the engine state created by
  *                                the common initiailizers.

drivers/gpu/drm/i915/intel_lrc.c

@@ -1230,7 +1230,7 @@ static int gen8_init_common_ring(struct intel_engine_cs *engine)
 
 	lrc_init_hws(engine);
 
-	intel_engine_reset_irq(engine);
+	intel_engine_reset_breadcrumbs(engine);
 
 	I915_WRITE(RING_HWSTAM(engine->mmio_base), 0xffffffff);
 

drivers/gpu/drm/i915/intel_ringbuffer.c

@@ -548,7 +548,7 @@ static int init_ring_common(struct intel_engine_cs *engine)
 	else
 		intel_ring_setup_status_page(engine);
 
-	intel_engine_reset_irq(engine);
+	intel_engine_reset_breadcrumbs(engine);
 
 	/* Enforce ordering by reading HEAD register back */
 	I915_READ_HEAD(engine);

drivers/gpu/drm/i915/intel_ringbuffer.h

@@ -520,7 +520,6 @@ int __intel_ring_space(int head, int tail, int size);
 void intel_ring_update_space(struct intel_ring *ring);
 
 void intel_engine_init_seqno(struct intel_engine_cs *engine, u32 seqno);
-void intel_engine_reset_irq(struct intel_engine_cs *engine);
 
 void intel_engine_setup_common(struct intel_engine_cs *engine);
 int intel_engine_init_common(struct intel_engine_cs *engine);
@@ -614,6 +613,7 @@ static inline bool intel_engine_wakeup(const struct intel_engine_cs *engine)
 	return wakeup;
 }
 
+void intel_engine_reset_breadcrumbs(struct intel_engine_cs *engine);
 void intel_engine_fini_breadcrumbs(struct intel_engine_cs *engine);
 unsigned int intel_kick_waiters(struct drm_i915_private *i915);
 unsigned int intel_kick_signalers(struct drm_i915_private *i915);