drm/amdgpu: fix a race in GPU reset with IB test (v2)

Split late_init into two functions, one (do_late_init) which
just does the hw init, and late_init which calls do_late_init
and schedules the IB test work.  Call do_late_init in
the GPU reset code to run the init code, but not schedule
the IB test code.  The IB test code is called directly
in the gpu reset code so no need to run the IB tests
in a separate work thread.  If we do, we end up racing.

v2: Rework late_init.  Pull out the mgpu fan boost and xgmi
pstate code into late_init so they get called in all cases.
rename the late_init worker thread to delayed work since it's
just the IB tests now which can happen later.  Schedule the
work at init and resume time.  It's not needed at reset time
because the IB tests are called directly.
Reviewed-by: Christian König <christian.koenig@amd.com>
Cc: Xinhui Pan <xinhui.pan@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu.h

@@ -922,7 +922,7 @@ struct amdgpu_device {
 	const struct amdgpu_df_funcs	*df_funcs;
 
 	/* delayed work_func for deferring clockgating during resume */
-	struct delayed_work     late_init_work;
+	struct delayed_work     delayed_init_work;
 
 	struct amdgpu_virt	virt;
 	/* firmware VRAM reservation */

drivers/gpu/drm/amd/amdgpu/amdgpu_device.c

@@ -1869,6 +1869,43 @@ static int amdgpu_device_set_pg_state(struct amdgpu_device *adev, enum amd_power
 	return 0;
 }
 
+static int amdgpu_device_enable_mgpu_fan_boost(void)
+{
+	struct amdgpu_gpu_instance *gpu_ins;
+	struct amdgpu_device *adev;
+	int i, ret = 0;
+
+	mutex_lock(&mgpu_info.mutex);
+
+	/*
+	 * MGPU fan boost feature should be enabled
+	 * only when there are two or more dGPUs in
+	 * the system
+	 */
+	if (mgpu_info.num_dgpu < 2)
+		goto out;
+
+	for (i = 0; i < mgpu_info.num_dgpu; i++) {
+		gpu_ins = &(mgpu_info.gpu_ins[i]);
+		adev = gpu_ins->adev;
+		if (!(adev->flags & AMD_IS_APU) &&
+		    !gpu_ins->mgpu_fan_enabled &&
+		    adev->powerplay.pp_funcs &&
+		    adev->powerplay.pp_funcs->enable_mgpu_fan_boost) {
+			ret = amdgpu_dpm_enable_mgpu_fan_boost(adev);
+			if (ret)
+				break;
+
+			gpu_ins->mgpu_fan_enabled = 1;
+		}
+	}
+
+out:
+	mutex_unlock(&mgpu_info.mutex);
+
+	return ret;
+}
+
 /**
  * amdgpu_device_ip_late_init - run late init for hardware IPs
  *
@@ -1902,11 +1939,15 @@ static int amdgpu_device_ip_late_init(struct amdgpu_device *adev)
 	amdgpu_device_set_cg_state(adev, AMD_CG_STATE_GATE);
 	amdgpu_device_set_pg_state(adev, AMD_PG_STATE_GATE);
 
-	queue_delayed_work(system_wq, &adev->late_init_work,
-			   msecs_to_jiffies(AMDGPU_RESUME_MS));
-
 	amdgpu_device_fill_reset_magic(adev);
 
+	r = amdgpu_device_enable_mgpu_fan_boost();
+	if (r)
+		DRM_ERROR("enable mgpu fan boost failed (%d).\n", r);
+
+	/* set to low pstate by default */
+	amdgpu_xgmi_set_pstate(adev, 0);
+
 	return 0;
 }
 
@@ -2005,65 +2046,20 @@ static int amdgpu_device_ip_fini(struct amdgpu_device *adev)
 	return 0;
 }
 
-static int amdgpu_device_enable_mgpu_fan_boost(void)
-{
-	struct amdgpu_gpu_instance *gpu_ins;
-	struct amdgpu_device *adev;
-	int i, ret = 0;
-
-	mutex_lock(&mgpu_info.mutex);
-
-	/*
-	 * MGPU fan boost feature should be enabled
-	 * only when there are two or more dGPUs in
-	 * the system
-	 */
-	if (mgpu_info.num_dgpu < 2)
-		goto out;
-
-	for (i = 0; i < mgpu_info.num_dgpu; i++) {
-		gpu_ins = &(mgpu_info.gpu_ins[i]);
-		adev = gpu_ins->adev;
-		if (!(adev->flags & AMD_IS_APU) &&
-		    !gpu_ins->mgpu_fan_enabled &&
-		    adev->powerplay.pp_funcs &&
-		    adev->powerplay.pp_funcs->enable_mgpu_fan_boost) {
-			ret = amdgpu_dpm_enable_mgpu_fan_boost(adev);
-			if (ret)
-				break;
-
-			gpu_ins->mgpu_fan_enabled = 1;
-		}
-	}
-
-out:
-	mutex_unlock(&mgpu_info.mutex);
-
-	return ret;
-}
-
 /**
- * amdgpu_device_ip_late_init_func_handler - work handler for ib test
+ * amdgpu_device_delayed_init_work_handler - work handler for IB tests
  *
  * @work: work_struct.
  */
-static void amdgpu_device_ip_late_init_func_handler(struct work_struct *work)
+static void amdgpu_device_delayed_init_work_handler(struct work_struct *work)
 {
 	struct amdgpu_device *adev =
-		container_of(work, struct amdgpu_device, late_init_work.work);
+		container_of(work, struct amdgpu_device, delayed_init_work.work);
 	int r;
 
 	r = amdgpu_ib_ring_tests(adev);
 	if (r)
 		DRM_ERROR("ib ring test failed (%d).\n", r);
-
-	r = amdgpu_device_enable_mgpu_fan_boost();
-	if (r)
-		DRM_ERROR("enable mgpu fan boost failed (%d).\n", r);
-
-	/*set to low pstate by default */
-	amdgpu_xgmi_set_pstate(adev, 0);
-
 }
 
 static void amdgpu_device_delay_enable_gfx_off(struct work_struct *work)
@@ -2535,8 +2531,8 @@ int amdgpu_device_init(struct amdgpu_device *adev,
 	INIT_LIST_HEAD(&adev->ring_lru_list);
 	spin_lock_init(&adev->ring_lru_list_lock);
 
-	INIT_DELAYED_WORK(&adev->late_init_work,
-			  amdgpu_device_ip_late_init_func_handler);
+	INIT_DELAYED_WORK(&adev->delayed_init_work,
+			  amdgpu_device_delayed_init_work_handler);
 	INIT_DELAYED_WORK(&adev->gfx.gfx_off_delay_work,
 			  amdgpu_device_delay_enable_gfx_off);
 
@@ -2749,6 +2745,9 @@ int amdgpu_device_init(struct amdgpu_device *adev,
 	/* must succeed. */
 	amdgpu_ras_resume(adev);
 
+	queue_delayed_work(system_wq, &adev->delayed_init_work,
+			   msecs_to_jiffies(AMDGPU_RESUME_MS));
+
 	r = device_create_file(adev->dev, &dev_attr_pcie_replay_count);
 	if (r) {
 		dev_err(adev->dev, "Could not create pcie_replay_count");
@@ -2796,7 +2795,7 @@ void amdgpu_device_fini(struct amdgpu_device *adev)
 		adev->firmware.gpu_info_fw = NULL;
 	}
 	adev->accel_working = false;
-	cancel_delayed_work_sync(&adev->late_init_work);
+	cancel_delayed_work_sync(&adev->delayed_init_work);
 	/* free i2c buses */
 	if (!amdgpu_device_has_dc_support(adev))
 		amdgpu_i2c_fini(adev);
@@ -2859,7 +2858,7 @@ int amdgpu_device_suspend(struct drm_device *dev, bool suspend, bool fbcon)
 	if (fbcon)
 		amdgpu_fbdev_set_suspend(adev, 1);
 
-	cancel_delayed_work_sync(&adev->late_init_work);
+	cancel_delayed_work_sync(&adev->delayed_init_work);
 
 	if (!amdgpu_device_has_dc_support(adev)) {
 		/* turn off display hw */
@@ -2979,6 +2978,9 @@ int amdgpu_device_resume(struct drm_device *dev, bool resume, bool fbcon)
 	if (r)
 		return r;
 
+	queue_delayed_work(system_wq, &adev->delayed_init_work,
+			   msecs_to_jiffies(AMDGPU_RESUME_MS));
+
 	if (!amdgpu_device_has_dc_support(adev)) {
 		/* pin cursors */
 		list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
@@ -3002,7 +3004,7 @@ int amdgpu_device_resume(struct drm_device *dev, bool resume, bool fbcon)
 		return r;
 
 	/* Make sure IB tests flushed */
-	flush_delayed_work(&adev->late_init_work);
+	flush_delayed_work(&adev->delayed_init_work);
 
 	/* blat the mode back in */
 	if (fbcon) {
@@ -3593,7 +3595,7 @@ int amdgpu_device_gpu_recover(struct amdgpu_device *adev,
 
 	dev_info(adev->dev, "GPU reset begin!\n");
 
-	cancel_delayed_work_sync(&adev->late_init_work);
+	cancel_delayed_work_sync(&adev->delayed_init_work);
 
 	hive = amdgpu_get_xgmi_hive(adev, false);
 

drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c

@@ -974,7 +974,7 @@ int amdgpu_driver_open_kms(struct drm_device *dev, struct drm_file *file_priv)
 	int r, pasid;
 
 	/* Ensure IB tests are run on ring */
-	flush_delayed_work(&adev->late_init_work);
+	flush_delayed_work(&adev->delayed_init_work);
 
 	file_priv->driver_priv = NULL;