drm/amd: Keep display off while going into S4

When userspace invokes S4 the flow is:

1) amdgpu_pmops_prepare()
2) amdgpu_pmops_freeze()
3) Create hibernation image
4) amdgpu_pmops_thaw()
5) Write out image to disk
6) Turn off system

Then on resume amdgpu_pmops_restore() is called.

This flow has a problem that because amdgpu_pmops_thaw() is called
it will call amdgpu_device_resume() which will resume all of the GPU.

This includes turning the display hardware back on and discovering
connectors again.

This is an unexpected experience for the display to turn back on.
Adjust the flow so that during the S4 sequence display hardware is
not turned back on.

Reported-by: Xaver Hugl <[email protected]>
Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/2038
Cc: Muhammad Usama Anjum <[email protected]>
Tested-by: Muhammad Usama Anjum <[email protected]>
Acked-by: Alex Deucher <[email protected]>
Acked-by: Harry Wentland <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Mario Limonciello <[email protected]>
Signed-off-by: Alex Deucher <[email protected]>

Author: superm1

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

@@ -2563,7 +2563,6 @@ static int amdgpu_pmops_freeze(struct device *dev)
 	int r;
 
 	r = amdgpu_device_suspend(drm_dev, true);
-	adev->in_s4 = false;
 	if (r)
 		return r;
 
@@ -2575,8 +2574,13 @@ 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);
+	struct amdgpu_device *adev = drm_to_adev(drm_dev);
+	int r;
 
-	return amdgpu_device_resume(drm_dev, true);
+	r = amdgpu_device_resume(drm_dev, true);
+	adev->in_s4 = false;
+
+	return r;
 }
 
 static int amdgpu_pmops_poweroff(struct device *dev)
@@ -2589,6 +2593,9 @@ static int amdgpu_pmops_poweroff(struct device *dev)
 static int amdgpu_pmops_restore(struct device *dev)
 {
 	struct drm_device *drm_dev = dev_get_drvdata(dev);
+	struct amdgpu_device *adev = drm_to_adev(drm_dev);
+
+	adev->in_s4 = false;
 
 	return amdgpu_device_resume(drm_dev, true);
 }

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

@@ -3434,6 +3434,11 @@ static int dm_resume(struct amdgpu_ip_block *ip_block)
 
 		return 0;
 	}
+
+	/* leave display off for S4 sequence */
+	if (adev->in_s4)
+		return 0;
+
 	/* Recreate dc_state - DC invalidates it when setting power state to S3. */
 	dc_state_release(dm_state->context);
 	dm_state->context = dc_state_create(dm->dc, NULL);