drm/i915/dgfx: Disable d3cold at gfx root port

Currently i915 disables d3cold for i915 pci dev.
This blocks D3 for i915 gfx pci upstream bridge (VSP).
Let's disable d3cold at gfx root port to make sure that
i915 gfx VSP can transition to D3 to save some power.

We don't need to disable/enable d3cold in rpm, s2idle
suspend/resume handlers. Disabling/Enabling d3cold at
gfx root port in probe/remove phase is sufficient.

Fixes: 1a085e23 ("drm/i915: Disable D3Cold in s2idle and runtime pm")
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Anshuman Gupta <anshuman.gupta@intel.com>
Reviewed-by: Badal Nilawar <badal.nilawar@intel.com>
Acked-by: : Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220616122249.5007-1-anshuman.gupta@intel.com

drivers/gpu/drm/i915/i915_driver.c

@@ -535,6 +535,7 @@ static int i915_set_dma_info(struct drm_i915_private *i915)
 static int i915_driver_hw_probe(struct drm_i915_private *dev_priv)
 {
 	struct pci_dev *pdev = to_pci_dev(dev_priv->drm.dev);
+	struct pci_dev *root_pdev;
 	int ret;
 
 	if (i915_inject_probe_failure(dev_priv))
@@ -646,6 +647,15 @@ static int i915_driver_hw_probe(struct drm_i915_private *dev_priv)
 
 	intel_bw_init_hw(dev_priv);
 
+	/*
+	 * FIXME: Temporary hammer to avoid freezing the machine on our DGFX
+	 * This should be totally removed when we handle the pci states properly
+	 * on runtime PM and on s2idle cases.
+	 */
+	root_pdev = pcie_find_root_port(pdev);
+	if (root_pdev)
+		pci_d3cold_disable(root_pdev);
+
 	return 0;
 
 err_msi:
@@ -669,11 +679,16 @@ static int i915_driver_hw_probe(struct drm_i915_private *dev_priv)
 static void i915_driver_hw_remove(struct drm_i915_private *dev_priv)
 {
 	struct pci_dev *pdev = to_pci_dev(dev_priv->drm.dev);
+	struct pci_dev *root_pdev;
 
 	i915_perf_fini(dev_priv);
 
 	if (pdev->msi_enabled)
 		pci_disable_msi(pdev);
+
+	root_pdev = pcie_find_root_port(pdev);
+	if (root_pdev)
+		pci_d3cold_enable(root_pdev);
 }
 
 /**
@@ -1191,14 +1206,6 @@ static int i915_drm_suspend_late(struct drm_device *dev, bool hibernation)
 		goto out;
 	}
 
-	/*
-	 * FIXME: Temporary hammer to avoid freezing the machine on our DGFX
-	 * This should be totally removed when we handle the pci states properly
-	 * on runtime PM and on s2idle cases.
-	 */
-	if (suspend_to_idle(dev_priv))
-		pci_d3cold_disable(pdev);
-
 	pci_disable_device(pdev);
 	/*
 	 * During hibernation on some platforms the BIOS may try to access
@@ -1363,8 +1370,6 @@ static int i915_drm_resume_early(struct drm_device *dev)
 
 	pci_set_master(pdev);
 
-	pci_d3cold_enable(pdev);
-
 	disable_rpm_wakeref_asserts(&dev_priv->runtime_pm);
 
 	ret = vlv_resume_prepare(dev_priv, false);
@@ -1541,7 +1546,6 @@ static int intel_runtime_suspend(struct device *kdev)
 {
 	struct drm_i915_private *dev_priv = kdev_to_i915(kdev);
 	struct intel_runtime_pm *rpm = &dev_priv->runtime_pm;
-	struct pci_dev *pdev = to_pci_dev(dev_priv->drm.dev);
 	int ret;
 
 	if (drm_WARN_ON_ONCE(&dev_priv->drm, !HAS_RUNTIME_PM(dev_priv)))
@@ -1587,12 +1591,6 @@ static int intel_runtime_suspend(struct device *kdev)
 		drm_err(&dev_priv->drm,
 			"Unclaimed access detected prior to suspending\n");
 
-	/*
-	 * FIXME: Temporary hammer to avoid freezing the machine on our DGFX
-	 * This should be totally removed when we handle the pci states properly
-	 * on runtime PM and on s2idle cases.
-	 */
-	pci_d3cold_disable(pdev);
 	rpm->suspended = true;
 
 	/*
@@ -1631,7 +1629,6 @@ static int intel_runtime_resume(struct device *kdev)
 {
 	struct drm_i915_private *dev_priv = kdev_to_i915(kdev);
 	struct intel_runtime_pm *rpm = &dev_priv->runtime_pm;
-	struct pci_dev *pdev = to_pci_dev(dev_priv->drm.dev);
 	int ret;
 
 	if (drm_WARN_ON_ONCE(&dev_priv->drm, !HAS_RUNTIME_PM(dev_priv)))
@@ -1644,7 +1641,6 @@ static int intel_runtime_resume(struct device *kdev)
 
 	intel_opregion_notify_adapter(dev_priv, PCI_D0);
 	rpm->suspended = false;
-	pci_d3cold_enable(pdev);
 	if (intel_uncore_unclaimed_mmio(&dev_priv->uncore))
 		drm_dbg(&dev_priv->drm,
 			"Unclaimed access during suspend, bios?\n");