drm/i915: Add control flags to i915_handle_error()

Not all callers want the GPU error to handled in the same way, so expose
a control parameter. In the first instance, some callers do not want the
heavyweight error capture so add a bit to request the state to be
captured and saved.

v2: Pass msg down to i915_reset/i915_reset_engine so that we include the
reason for the reset in the dev_notice(), superseding the earlier option
to not print that notice.
v3: Stash the reason inside the i915->gpu_error to handover to the direct
reset from the blocking waiter.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jeff McGee <jeff.mcgee@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Cc: Michel Thierry <michel.thierry@intel.com>
Reviewed-by: Michel Thierry <michel.thierry@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180320100449.1360-2-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_debugfs.c

@@ -4011,8 +4011,8 @@ i915_wedged_set(void *data, u64 val)
 		engine->hangcheck.stalled = true;
 	}
 
-	i915_handle_error(i915, val, "Manually set wedged engine mask = %llx",
-			  val);
+	i915_handle_error(i915, val, I915_ERROR_CAPTURE,
+			  "Manually set wedged engine mask = %llx", val);
 
 	wait_on_bit(&i915->gpu_error.flags,
 		    I915_RESET_HANDOFF,

drivers/gpu/drm/i915/i915_drv.c

@@ -1873,7 +1873,6 @@ static int i915_resume_switcheroo(struct drm_device *dev)
 /**
  * i915_reset - reset chip after a hang
  * @i915: #drm_i915_private to reset
- * @flags: Instructions
  *
  * Reset the chip.  Useful if a hang is detected. Marks the device as wedged
  * on failure.
@@ -1888,7 +1887,7 @@ static int i915_resume_switcheroo(struct drm_device *dev)
  *   - re-init interrupt state
  *   - re-init display
  */
-void i915_reset(struct drm_i915_private *i915, unsigned int flags)
+void i915_reset(struct drm_i915_private *i915)
 {
 	struct i915_gpu_error *error = &i915->gpu_error;
 	int ret;
@@ -1905,8 +1904,9 @@ void i915_reset(struct drm_i915_private *i915, unsigned int flags)
 	if (!i915_gem_unset_wedged(i915))
 		goto wakeup;
 
-	if (!(flags & I915_RESET_QUIET))
-		dev_notice(i915->drm.dev, "Resetting chip after gpu hang\n");
+	if (error->reason)
+		dev_notice(i915->drm.dev,
+			   "Resetting chip for %s\n", error->reason);
 	error->reset_count++;
 
 	disable_irq(i915->drm.irq);
@@ -2007,7 +2007,7 @@ static inline int intel_gt_reset_engine(struct drm_i915_private *dev_priv,
 /**
  * i915_reset_engine - reset GPU engine to recover from a hang
  * @engine: engine to reset
- * @flags: options
+ * @msg: reason for GPU reset; or NULL for no dev_notice()
  *
  * Reset a specific GPU engine. Useful if a hang is detected.
  * Returns zero on successful reset or otherwise an error code.
@@ -2017,7 +2017,7 @@ static inline int intel_gt_reset_engine(struct drm_i915_private *dev_priv,
  *  - reset engine (which will force the engine to idle)
  *  - re-init/configure engine
  */
-int i915_reset_engine(struct intel_engine_cs *engine, unsigned int flags)
+int i915_reset_engine(struct intel_engine_cs *engine, const char *msg)
 {
 	struct i915_gpu_error *error = &engine->i915->gpu_error;
 	struct i915_request *active_request;
@@ -2032,10 +2032,9 @@ int i915_reset_engine(struct intel_engine_cs *engine, unsigned int flags)
 		goto out;
 	}
 
-	if (!(flags & I915_RESET_QUIET)) {
+	if (msg)
 		dev_notice(engine->i915->drm.dev,
-			   "Resetting %s after gpu hang\n", engine->name);
-	}
+			   "Resetting %s for %s\n", engine->name, msg);
 	error->reset_engine_count[engine->id]++;
 
 	if (!engine->i915->guc.execbuf_client)

drivers/gpu/drm/i915/i915_drv.h

@@ -2700,10 +2700,8 @@ extern void i915_driver_unload(struct drm_device *dev);
 extern int intel_gpu_reset(struct drm_i915_private *dev_priv, u32 engine_mask);
 extern bool intel_has_gpu_reset(struct drm_i915_private *dev_priv);
 
-#define I915_RESET_QUIET BIT(0)
-extern void i915_reset(struct drm_i915_private *i915, unsigned int flags);
-extern int i915_reset_engine(struct intel_engine_cs *engine,
-			     unsigned int flags);
+extern void i915_reset(struct drm_i915_private *i915);
+extern int i915_reset_engine(struct intel_engine_cs *engine, const char *msg);
 
 extern bool intel_has_reset_engine(struct drm_i915_private *dev_priv);
 extern int intel_reset_guc(struct drm_i915_private *dev_priv);
@@ -2751,10 +2749,12 @@ static inline void i915_queue_hangcheck(struct drm_i915_private *dev_priv)
 			   &dev_priv->gpu_error.hangcheck_work, delay);
 }
 
-__printf(3, 4)
+__printf(4, 5)
 void i915_handle_error(struct drm_i915_private *dev_priv,
 		       u32 engine_mask,
+		       unsigned long flags,
 		       const char *fmt, ...);
+#define I915_ERROR_CAPTURE BIT(0)
 
 extern void intel_irq_init(struct drm_i915_private *dev_priv);
 extern void intel_irq_fini(struct drm_i915_private *dev_priv);

drivers/gpu/drm/i915/i915_gpu_error.h

@@ -269,6 +269,9 @@ struct i915_gpu_error {
 	/** Number of times an engine has been reset */
 	u32 reset_engine_count[I915_NUM_ENGINES];
 
+	/** Reason for the current *global* reset */
+	const char *reason;
+
 	/**
 	 * Waitqueue to signal when a hang is detected. Used to for waiters
 	 * to release the struct_mutex for the reset to procede.

drivers/gpu/drm/i915/i915_irq.c

@@ -2877,15 +2877,10 @@ static irqreturn_t gen11_irq_handler(int irq, void *arg)
 	return IRQ_HANDLED;
 }
 
-/**
- * i915_reset_device - do process context error handling work
- * @dev_priv: i915 device private
- *
- * Fire an error uevent so userspace can see that a hang or error
- * was detected.
- */
-static void i915_reset_device(struct drm_i915_private *dev_priv)
+static void i915_reset_device(struct drm_i915_private *dev_priv,
+			      const char *msg)
 {
+	struct i915_gpu_error *error = &dev_priv->gpu_error;
 	struct kobject *kobj = &dev_priv->drm.primary->kdev->kobj;
 	char *error_event[] = { I915_ERROR_UEVENT "=1", NULL };
 	char *reset_event[] = { I915_RESET_UEVENT "=1", NULL };
@@ -2901,29 +2896,32 @@ static void i915_reset_device(struct drm_i915_private *dev_priv)
 	i915_wedge_on_timeout(&w, dev_priv, 5*HZ) {
 		intel_prepare_reset(dev_priv);
 
+		error->reason = msg;
+
 		/* Signal that locked waiters should reset the GPU */
-		set_bit(I915_RESET_HANDOFF, &dev_priv->gpu_error.flags);
-		wake_up_all(&dev_priv->gpu_error.wait_queue);
+		set_bit(I915_RESET_HANDOFF, &error->flags);
+		wake_up_all(&error->wait_queue);
 
 		/* Wait for anyone holding the lock to wakeup, without
 		 * blocking indefinitely on struct_mutex.
 		 */
 		do {
 			if (mutex_trylock(&dev_priv->drm.struct_mutex)) {
-				i915_reset(dev_priv, 0);
+				i915_reset(dev_priv);
 				mutex_unlock(&dev_priv->drm.struct_mutex);
 			}
-		} while (wait_on_bit_timeout(&dev_priv->gpu_error.flags,
+		} while (wait_on_bit_timeout(&error->flags,
 					     I915_RESET_HANDOFF,
 					     TASK_UNINTERRUPTIBLE,
 					     1));
 
+		error->reason = NULL;
+
 		intel_finish_reset(dev_priv);
 	}
 
-	if (!test_bit(I915_WEDGED, &dev_priv->gpu_error.flags))
-		kobject_uevent_env(kobj,
-				   KOBJ_CHANGE, reset_done_event);
+	if (!test_bit(I915_WEDGED, &error->flags))
+		kobject_uevent_env(kobj, KOBJ_CHANGE, reset_done_event);
 }
 
 static void i915_clear_error_registers(struct drm_i915_private *dev_priv)
@@ -2955,6 +2953,7 @@ static void i915_clear_error_registers(struct drm_i915_private *dev_priv)
  * i915_handle_error - handle a gpu error
  * @dev_priv: i915 device private
  * @engine_mask: mask representing engines that are hung
+ * @flags: control flags
  * @fmt: Error message format string
  *
  * Do some basic checking of register state at error time and
@@ -2965,16 +2964,23 @@ static void i915_clear_error_registers(struct drm_i915_private *dev_priv)
  */
 void i915_handle_error(struct drm_i915_private *dev_priv,
 		       u32 engine_mask,
+		       unsigned long flags,
 		       const char *fmt, ...)
 {
 	struct intel_engine_cs *engine;
 	unsigned int tmp;
-	va_list args;
 	char error_msg[80];
+	char *msg = NULL;
 
-	va_start(args, fmt);
-	vscnprintf(error_msg, sizeof(error_msg), fmt, args);
-	va_end(args);
+	if (fmt) {
+		va_list args;
+
+		va_start(args, fmt);
+		vscnprintf(error_msg, sizeof(error_msg), fmt, args);
+		va_end(args);
+
+		msg = error_msg;
+	}
 
 	/*
 	 * In most cases it's guaranteed that we get here with an RPM
@@ -2986,8 +2992,11 @@ void i915_handle_error(struct drm_i915_private *dev_priv,
 	intel_runtime_pm_get(dev_priv);
 
 	engine_mask &= INTEL_INFO(dev_priv)->ring_mask;
-	i915_capture_error_state(dev_priv, engine_mask, error_msg);
-	i915_clear_error_registers(dev_priv);
+
+	if (flags & I915_ERROR_CAPTURE) {
+		i915_capture_error_state(dev_priv, engine_mask, msg);
+		i915_clear_error_registers(dev_priv);
+	}
 
 	/*
 	 * Try engine reset when available. We fall back to full reset if
@@ -3000,7 +3009,7 @@ void i915_handle_error(struct drm_i915_private *dev_priv,
 					     &dev_priv->gpu_error.flags))
 				continue;
 
-			if (i915_reset_engine(engine, 0) == 0)
+			if (i915_reset_engine(engine, msg) == 0)
 				engine_mask &= ~intel_engine_flag(engine);
 
 			clear_bit(I915_RESET_ENGINE + engine->id,
@@ -3030,7 +3039,7 @@ void i915_handle_error(struct drm_i915_private *dev_priv,
 				    TASK_UNINTERRUPTIBLE);
 	}
 
-	i915_reset_device(dev_priv);
+	i915_reset_device(dev_priv, msg);
 
 	for_each_engine(engine, dev_priv, tmp) {
 		clear_bit(I915_RESET_ENGINE + engine->id,

drivers/gpu/drm/i915/i915_request.c

@@ -1229,7 +1229,7 @@ static bool __i915_wait_request_check_and_reset(struct i915_request *request)
 		return false;
 
 	__set_current_state(TASK_RUNNING);
-	i915_reset(request->i915, 0);
+	i915_reset(request->i915);
 	return true;
 }
 

drivers/gpu/drm/i915/intel_hangcheck.c

@@ -246,9 +246,8 @@ engine_stuck(struct intel_engine_cs *engine, u64 acthd)
 	 */
 	tmp = I915_READ_CTL(engine);
 	if (tmp & RING_WAIT) {
-		i915_handle_error(dev_priv, BIT(engine->id),
-				  "Kicking stuck wait on %s",
-				  engine->name);
+		i915_handle_error(dev_priv, BIT(engine->id), 0,
+				  "stuck wait on %s", engine->name);
 		I915_WRITE_CTL(engine, tmp);
 		return ENGINE_WAIT_KICK;
 	}
@@ -258,8 +257,8 @@ engine_stuck(struct intel_engine_cs *engine, u64 acthd)
 		default:
 			return ENGINE_DEAD;
 		case 1:
-			i915_handle_error(dev_priv, ALL_ENGINES,
-					  "Kicking stuck semaphore on %s",
+			i915_handle_error(dev_priv, ALL_ENGINES, 0,
+					  "stuck semaphore on %s",
 					  engine->name);
 			I915_WRITE_CTL(engine, tmp);
 			return ENGINE_WAIT_KICK;
@@ -386,13 +385,13 @@ static void hangcheck_declare_hang(struct drm_i915_private *i915,
 	if (stuck != hung)
 		hung &= ~stuck;
 	len = scnprintf(msg, sizeof(msg),
-			"%s on ", stuck == hung ? "No progress" : "Hang");
+			"%s on ", stuck == hung ? "no progress" : "hang");
 	for_each_engine_masked(engine, i915, hung, tmp)
 		len += scnprintf(msg + len, sizeof(msg) - len,
 				 "%s, ", engine->name);
 	msg[len-2] = '\0';
 
-	return i915_handle_error(i915, hung, "%s", msg);
+	return i915_handle_error(i915, hung, I915_ERROR_CAPTURE, "%s", msg);
 }
 
 /*

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

@@ -433,7 +433,7 @@ static int igt_global_reset(void *arg)
 	mutex_lock(&i915->drm.struct_mutex);
 	reset_count = i915_reset_count(&i915->gpu_error);
 
-	i915_reset(i915, I915_RESET_QUIET);
+	i915_reset(i915);
 
 	if (i915_reset_count(&i915->gpu_error) == reset_count) {
 		pr_err("No GPU reset recorded!\n");
@@ -518,7 +518,7 @@ static int __igt_reset_engine(struct drm_i915_private *i915, bool active)
 			engine->hangcheck.seqno =
 				intel_engine_get_seqno(engine);
 
-			err = i915_reset_engine(engine, I915_RESET_QUIET);
+			err = i915_reset_engine(engine, NULL);
 			if (err) {
 				pr_err("i915_reset_engine failed\n");
 				break;
@@ -725,7 +725,7 @@ static int __igt_reset_engine_others(struct drm_i915_private *i915,
 			engine->hangcheck.seqno =
 				intel_engine_get_seqno(engine);
 
-			err = i915_reset_engine(engine, I915_RESET_QUIET);
+			err = i915_reset_engine(engine, NULL);
 			if (err) {
 				pr_err("i915_reset_engine(%s:%s) failed, err=%d\n",
 				       engine->name, active ? "active" : "idle", err);
@@ -865,7 +865,6 @@ static int igt_wait_reset(void *arg)
 		       __func__, rq->fence.seqno, hws_seqno(&h, rq));
 		intel_engine_dump(rq->engine, &p, "%s\n", rq->engine->name);
 
-		i915_reset(i915, 0);
 		i915_gem_set_wedged(i915);
 
 		err = -EIO;
@@ -962,7 +961,6 @@ static int igt_reset_queue(void *arg)
 				i915_request_put(rq);
 				i915_request_put(prev);
 
-				i915_reset(i915, 0);
 				i915_gem_set_wedged(i915);
 
 				err = -EIO;
@@ -971,7 +969,7 @@ static int igt_reset_queue(void *arg)
 
 			reset_count = fake_hangcheck(prev);
 
-			i915_reset(i915, I915_RESET_QUIET);
+			i915_reset(i915);
 
 			GEM_BUG_ON(test_bit(I915_RESET_HANDOFF,
 					    &i915->gpu_error.flags));
@@ -1069,7 +1067,6 @@ static int igt_handle_error(void *arg)
 		       __func__, rq->fence.seqno, hws_seqno(&h, rq));
 		intel_engine_dump(rq->engine, &p, "%s\n", rq->engine->name);
 
-		i915_reset(i915, 0);
 		i915_gem_set_wedged(i915);
 
 		err = -EIO;
@@ -1084,7 +1081,7 @@ static int igt_handle_error(void *arg)
 	engine->hangcheck.stalled = true;
 	engine->hangcheck.seqno = intel_engine_get_seqno(engine);
 
-	i915_handle_error(i915, intel_engine_flag(engine), "%s", __func__);
+	i915_handle_error(i915, intel_engine_flag(engine), 0, NULL);
 
 	xchg(&i915->gpu_error.first_error, error);