[PATCH v4 2/8] drm/amdgpu: Block all job scheduling activity during DPC recovery

[Andrey Grodzovsky]

DPC recovery involves ASIC reset just as normal GPU recovery so block
SW GPU schedulers and wait on all concurrent GPU resets.

Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky at amd.com>
Acked-by: Alex Deucher <alexander.deucher at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 57 +++++++++++++++++++++++++++---
 1 file changed, 53 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index 1fbf8a1..e999f1f 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -4740,6 +4740,20 @@ int amdgpu_device_baco_exit(struct drm_device *dev)
 	return 0;
 }
 
+static void amdgpu_cancel_all_tdr(struct amdgpu_device *adev)
+{
+	int i;
+
+	for (i = 0; i < AMDGPU_MAX_RINGS; ++i) {
+		struct amdgpu_ring *ring = adev->rings[i];
+
+		if (!ring || !ring->sched.thread)
+			continue;
+
+		cancel_delayed_work_sync(&ring->sched.work_tdr);
+	}
+}
+
 /**
  * amdgpu_pci_error_detected - Called when a PCI error is detected.
  * @pdev: PCI device struct
@@ -4753,15 +4767,37 @@ pci_ers_result_t amdgpu_pci_error_detected(struct pci_dev *pdev, pci_channel_sta
 {
 	struct drm_device *dev = pci_get_drvdata(pdev);
 	struct amdgpu_device *adev = drm_to_adev(dev);
+	int i;
 
 	DRM_INFO("PCI error: detected callback, state(%d)!!\n", state);
 
 	switch (state) {
 	case pci_channel_io_normal:
 		return PCI_ERS_RESULT_CAN_RECOVER;
-	case pci_channel_io_frozen:
-		/* Fatal error, prepare for slot reset */
-		amdgpu_device_lock_adev(adev);
+	/* Fatal error, prepare for slot reset */
+	case pci_channel_io_frozen:		
+		/*		
+		 * Cancel and wait for all TDRs in progress if failing to
+		 * set  adev->in_gpu_reset in amdgpu_device_lock_adev
+		 *
+		 * Locking adev->reset_sem will prevent any external access
+		 * to GPU during PCI error recovery
+		 */
+		while (!amdgpu_device_lock_adev(adev, NULL))
+			amdgpu_cancel_all_tdr(adev);
+
+		/*
+		 * Block any work scheduling as we do for regular GPU reset
+		 * for the duration of the recovery
+		 */
+		for (i = 0; i < AMDGPU_MAX_RINGS; ++i) {
+			struct amdgpu_ring *ring = adev->rings[i];
+
+			if (!ring || !ring->sched.thread)
+				continue;
+
+			drm_sched_stop(&ring->sched, NULL);
+		}
 		return PCI_ERS_RESULT_NEED_RESET;
 	case pci_channel_io_perm_failure:
 		/* Permanent error, prepare for device removal */
@@ -4894,8 +4930,21 @@ void amdgpu_pci_resume(struct pci_dev *pdev)
 {
 	struct drm_device *dev = pci_get_drvdata(pdev);
 	struct amdgpu_device *adev = drm_to_adev(dev);
+	int i;
 
-	amdgpu_device_unlock_adev(adev);
 
 	DRM_INFO("PCI error: resume callback!!\n");
+
+	for (i = 0; i < AMDGPU_MAX_RINGS; ++i) {
+		struct amdgpu_ring *ring = adev->rings[i];
+
+		if (!ring || !ring->sched.thread)
+			continue;
+
+
+		drm_sched_resubmit_jobs(&ring->sched);
+		drm_sched_start(&ring->sched, true);
+	}
+
+	amdgpu_device_unlock_adev(adev);
 }
-- 
2.7.4