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Commit 12471ba8 authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915: Harden detection of missed interrupts 



Only declare a missed interrupt if we find that the GPU is idle with
waiters and a hangcheck interval has passed in which no new user
interrupts have been raised.

v2: Clear the stuck interrupt marker between successful batches

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: default avatarMika Kuoppala <mika.kuoppala@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1460195877-20520-3-git-send-email-chris@chris-wilson.co.uk
parent c04e0f3b

drivers/gpu/drm/i915/i915_debugfs.c

+7 −4
Original line number Diff line number Diff line
@@ -728,10 +728,10 @@ static int i915_gem_request_info(struct seq_file *m, void *data) 
static void i915_ring_seqno_info(struct seq_file *m,

				 struct intel_engine_cs *engine)

{

	if (engine->get_seqno) {

	seq_printf(m, "Current sequence (%s): %x\n",

		   engine->name, engine->get_seqno(engine));

	}

	seq_printf(m, "Current user interrupts (%s): %x\n",

		   engine->name, READ_ONCE(engine->user_interrupts));

}



static int i915_gem_seqno_info(struct seq_file *m, void *data)
@@ -1367,6 +1367,9 @@ static int i915_hangcheck_info(struct seq_file *m, void *unused) 
			   engine->hangcheck.seqno,

			   seqno[id],

			   engine->last_submitted_seqno);

		seq_printf(m, "\tuser interrupts = %x [current %x]\n",

			   engine->hangcheck.user_interrupts,

			   READ_ONCE(engine->user_interrupts));

		seq_printf(m, "\tACTHD = 0x%08llx [current 0x%08llx]\n",

			   (long long)engine->hangcheck.acthd,

			   (long long)acthd[id]);

drivers/gpu/drm/i915/i915_irq.c

+26 −12
Original line number Diff line number Diff line
@@ -1000,6 +1000,7 @@ static void notify_ring(struct intel_engine_cs *engine) 
		return;



	trace_i915_gem_request_notify(engine);

	engine->user_interrupts++;



	wake_up_all(&engine->irq_queue);

}
@@ -3054,6 +3055,24 @@ ring_stuck(struct intel_engine_cs *engine, u64 acthd) 
	return HANGCHECK_HUNG;

}



static unsigned kick_waiters(struct intel_engine_cs *engine)

{

	struct drm_i915_private *i915 = to_i915(engine->dev);

	unsigned user_interrupts = READ_ONCE(engine->user_interrupts);



	if (engine->hangcheck.user_interrupts == user_interrupts &&

	    !test_and_set_bit(engine->id, &i915->gpu_error.missed_irq_rings)) {

		if (!(i915->gpu_error.test_irq_rings & intel_engine_flag(engine)))

			DRM_ERROR("Hangcheck timer elapsed... %s idle\n",

				  engine->name);

		else

			DRM_INFO("Fake missed irq on %s\n",

				 engine->name);

		wake_up_all(&engine->irq_queue);

	}



	return user_interrupts;

}

/*

 * 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
@@ -3096,6 +3115,7 @@ static void i915_hangcheck_elapsed(struct work_struct *work) 
	for_each_engine_id(engine, dev_priv, id) {

		u64 acthd;

		u32 seqno;

		unsigned user_interrupts;

		bool busy = true;



		semaphore_clear_deadlocks(dev_priv);
@@ -3113,22 +3133,15 @@ static void i915_hangcheck_elapsed(struct work_struct *work) 
		acthd = intel_ring_get_active_head(engine);

		seqno = engine->get_seqno(engine);



		/* Reset stuck interrupts between batch advances */

		user_interrupts = 0;



		if (engine->hangcheck.seqno == seqno) {

			if (ring_idle(engine, seqno)) {

				engine->hangcheck.action = HANGCHECK_IDLE;



				if (waitqueue_active(&engine->irq_queue)) {

					/* Issue a wake-up to catch stuck h/w. */

					if (!test_and_set_bit(engine->id, &dev_priv->gpu_error.missed_irq_rings)) {

						if (!(dev_priv->gpu_error.test_irq_rings & intel_engine_flag(engine)))

							DRM_ERROR("Hangcheck timer elapsed... %s idle\n",

								  engine->name);

						else

							DRM_INFO("Fake missed irq on %s\n",

								 engine->name);

						wake_up_all(&engine->irq_queue);

					}

					/* Safeguard against driver failure */

					user_interrupts = kick_waiters(engine);

					engine->hangcheck.score += BUSY;

				} else

					busy = false;
@@ -3179,7 +3192,7 @@ static void i915_hangcheck_elapsed(struct work_struct *work) 
				engine->hangcheck.score = 0;



			/* Clear head and subunit states on seqno movement */

			engine->hangcheck.acthd = 0;

			acthd = 0;



			memset(engine->hangcheck.instdone, 0,

			       sizeof(engine->hangcheck.instdone));
@@ -3187,6 +3200,7 @@ static void i915_hangcheck_elapsed(struct work_struct *work) 


		engine->hangcheck.seqno = seqno;

		engine->hangcheck.acthd = acthd;

		engine->hangcheck.user_interrupts = user_interrupts;

		busy_count += busy;

	}

drivers/gpu/drm/i915/intel_ringbuffer.h

+2 −0
Original line number Diff line number Diff line
@@ -87,6 +87,7 @@ enum intel_ring_hangcheck_action { 
struct intel_ring_hangcheck {

	u64 acthd;

	u32 seqno;

	unsigned user_interrupts;

	int score;

	enum intel_ring_hangcheck_action action;

	int deadlock;
@@ -305,6 +306,7 @@ struct intel_engine_cs { 
	 * inspecting request list.

	 */

	u32 last_submitted_seqno;

	unsigned user_interrupts;



	bool gpu_caches_dirty;