i915 / PM: Fix hibernate regression caused by suspend/resume splitting

Commit 84b79f8 (drm/i915: Fix crash
while aborting hibernation) attempted to fix a regression introduced
by commit cbda12d (drm/i915:
implement new pm ops for i915), but it went too far trying to split
the freeze/suspend and resume/thaw parts of the code.  As a result,
it introduced another regression, which only is visible on some systems.

Fix the problem by merging i915_drm_suspend() with
i915_drm_freeze() and moving some code from i915_resume()
into i915_drm_thaw(), so that intel_opregion_free() and
intel_opregion_init() are also executed in the freeze and thaw code
paths, respectively.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Reported-and-tested-by: Pedro Ribeiro <pedrib@gmail.com>
Tested-by: Tino Keitel <tino.keitel@tikei.de>
Acked-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/gpu/drm/i915/i915_drv.c

@@ -176,6 +176,8 @@ MODULE_DEVICE_TABLE(pci, pciidlist);
 
 static int i915_drm_freeze(struct drm_device *dev)
 {
+	struct drm_i915_private *dev_priv = dev->dev_private;
+
 	pci_save_state(dev->pdev);
 
 	/* If KMS is active, we do the leavevt stuff here */
@@ -191,17 +193,12 @@ static int i915_drm_freeze(struct drm_device *dev)
 
 	i915_save_state(dev);
 
-	return 0;
-}
-
-static void i915_drm_suspend(struct drm_device *dev)
-{
-	struct drm_i915_private *dev_priv = dev->dev_private;
-
 	intel_opregion_free(dev, 1);
 
 	/* Modeset on resume, not lid events */
 	dev_priv->modeset_on_lid = 0;
+
+	return 0;
 }
 
 static int i915_suspend(struct drm_device *dev, pm_message_t state)
@@ -221,8 +218,6 @@ static int i915_suspend(struct drm_device *dev, pm_message_t state)
 	if (error)
 		return error;
 
-	i915_drm_suspend(dev);
-
 	if (state.event == PM_EVENT_SUSPEND) {
 		/* Shut down the device */
 		pci_disable_device(dev->pdev);
@@ -237,6 +232,10 @@ static int i915_drm_thaw(struct drm_device *dev)
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	int error = 0;
 
+	i915_restore_state(dev);
+
+	intel_opregion_init(dev, 1);
+
 	/* KMS EnterVT equivalent */
 	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
 		mutex_lock(&dev->struct_mutex);
@@ -263,10 +262,6 @@ static int i915_resume(struct drm_device *dev)
 
 	pci_set_master(dev->pdev);
 
-	i915_restore_state(dev);
-
-	intel_opregion_init(dev, 1);
-
 	return i915_drm_thaw(dev);
 }
 
@@ -423,8 +418,6 @@ static int i915_pm_suspend(struct device *dev)
 	if (error)
 		return error;
 
-	i915_drm_suspend(drm_dev);
-
 	pci_disable_device(pdev);
 	pci_set_power_state(pdev, PCI_D3hot);
 
@@ -464,13 +457,8 @@ static int i915_pm_poweroff(struct device *dev)
 {
 	struct pci_dev *pdev = to_pci_dev(dev);
 	struct drm_device *drm_dev = pci_get_drvdata(pdev);
-	int error;
-
-	error = i915_drm_freeze(drm_dev);
-	if (!error)
-		i915_drm_suspend(drm_dev);
 
-	return error;
+	return i915_drm_freeze(drm_dev);
 }
 
 const struct dev_pm_ops i915_pm_ops = {