[PATCH v4 5/5] drm/amdgpu: do not resume device in thaw for normal hibernation

[Samuel Zhang <guoqing.zhang@amd.com>]

For normal hibernation, GPU do not need to be resumed in thaw since it is
not involved in writing the hibernation image. Skip resume in this case
can reduce the hibernation time.

On VM with 8 * 192GB VRAM dGPUs, 98% VRAM usage and 1.7TB system memory,
this can save 50 minutes.

Signed-off-by: Samuel Zhang <guoqing.zhang@amd.com>
Reviewed-by: Lijo Lazar <lijo.lazar@amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
index 4f8632737574..c37285a8b2c5 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
@@ -2541,6 +2541,10 @@ amdgpu_pci_shutdown(struct pci_dev *pdev)
 	if (amdgpu_ras_intr_triggered())
 		return;
 
+	/* device maybe not resumed here, return immediately in this case */
+	if (adev->in_s4 && adev->in_suspend)
+		return;
+
 	/* if we are running in a VM, make sure the device
 	 * torn down properly on reboot/shutdown.
 	 * unfortunately we can't detect certain
@@ -2654,8 +2658,17 @@ static int amdgpu_pmops_freeze(struct device *dev)
 static int amdgpu_pmops_thaw(struct device *dev)
 {
 	struct drm_device *drm_dev = dev_get_drvdata(dev);
+	int event = pm_transition_event();
 
-	return amdgpu_device_resume(drm_dev, true);
+	switch (event) {
+	case PM_EVENT_THAW: /* normal case */
+		return 0;
+	case PM_EVENT_RECOVER: /* error case */
+		return amdgpu_device_resume(drm_dev, true);
+	default:
+		dev_err(dev, "unknown pm_transition_event %d\n", event);
+		return -EOPNOTSUPP;
+	}
 }
 
 static int amdgpu_pmops_poweroff(struct device *dev)
-- 
2.43.5