3 files changed, 54 insertions, 10 deletions

diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index 3bed6beda051..6a67cdbd0e6a 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -1224,11 +1224,14 @@ static int pci_pm_runtime_suspend(struct device *dev)
 	int error;
 
 	/*
-	 * If pci_dev->driver is not set (unbound), the device should
-	 * always remain in D0 regardless of the runtime PM status
+	 * If pci_dev->driver is not set (unbound), we leave the device in D0,
+	 * but it may go to D3cold when the bridge above it runtime suspends.
+	 * Save its config space in case that happens.
 	 */
-	if (!pci_dev->driver)
+	if (!pci_dev->driver) {
+		pci_save_state(pci_dev);
 		return 0;
+	}
 
 	if (!pm || !pm->runtime_suspend)
 		return -ENOSYS;
@@ -1276,16 +1279,18 @@ static int pci_pm_runtime_resume(struct device *dev)
 	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
 
 	/*
-	 * If pci_dev->driver is not set (unbound), the device should
-	 * always remain in D0 regardless of the runtime PM status
+	 * Restoring config space is necessary even if the device is not bound
+	 * to a driver because although we left it in D0, it may have gone to
+	 * D3cold when the bridge above it runtime suspended.
 	 */
+	pci_restore_standard_config(pci_dev);
+
 	if (!pci_dev->driver)
 		return 0;
 
 	if (!pm || !pm->runtime_resume)
 		return -ENOSYS;
 
-	pci_restore_standard_config(pci_dev);
 	pci_fixup_device(pci_fixup_resume_early, pci_dev);
 	pci_enable_wake(pci_dev, PCI_D0, false);
 	pci_fixup_device(pci_fixup_resume, pci_dev);
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index f6a4dd10d9b0..bd6f156dc3cf 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -800,7 +800,7 @@ static int pci_wakeup(struct pci_dev *pci_dev, void *ign)
  * pci_wakeup_bus - Walk given bus and wake up devices on it
  * @bus: Top bus of the subtree to walk.
  */
-static void pci_wakeup_bus(struct pci_bus *bus)
+void pci_wakeup_bus(struct pci_bus *bus)
 {
 	if (bus)
 		pci_walk_bus(bus, pci_wakeup, NULL);
@@ -850,11 +850,11 @@ static int __pci_dev_set_current_state(struct pci_dev *dev, void *data)
 }
 
 /**
- * __pci_bus_set_current_state - Walk given bus and set current state of devices
+ * pci_bus_set_current_state - Walk given bus and set current state of devices
  * @bus: Top bus of the subtree to walk.
  * @state: state to be set
  */
-static void __pci_bus_set_current_state(struct pci_bus *bus, pci_power_t state)
+void pci_bus_set_current_state(struct pci_bus *bus, pci_power_t state)
 {
 	if (bus)
 		pci_walk_bus(bus, __pci_dev_set_current_state, &state);
@@ -876,7 +876,7 @@ int __pci_complete_power_transition(struct pci_dev *dev, pci_power_t state)
 	ret = pci_platform_power_transition(dev, state);
 	/* Power off the bridge may power off the whole hierarchy */
 	if (!ret && state == PCI_D3cold)
-		__pci_bus_set_current_state(dev->subordinate, PCI_D3cold);
+		pci_bus_set_current_state(dev->subordinate, PCI_D3cold);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(__pci_complete_power_transition);
diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index fc734014206f..ec582d37c189 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -26,6 +26,7 @@
 #include <linux/ktime.h>
 #include <linux/mm.h>
 #include <linux/platform_data/x86/apple.h>
+#include <linux/pm_runtime.h>
 #include <asm/dma.h>	/* isa_dma_bridge_buggy */
 #include "pci.h"
 
@@ -4832,3 +4833,41 @@ static void quirk_fsl_no_msi(struct pci_dev *pdev)
 		pdev->no_msi = 1;
 }
 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_FREESCALE, PCI_ANY_ID, quirk_fsl_no_msi);
+
+/*
+ * GPUs with integrated HDA controller for streaming audio to attached displays
+ * need a device link from the HDA controller (consumer) to the GPU (supplier)
+ * so that the GPU is powered up whenever the HDA controller is accessed.
+ * The GPU and HDA controller are functions 0 and 1 of the same PCI device.
+ * The device link stays in place until shutdown (or removal of the PCI device
+ * if it's hotplugged).  Runtime PM is allowed by default on the HDA controller
+ * to prevent it from permanently keeping the GPU awake.
+ */
+static void quirk_gpu_hda(struct pci_dev *hda)
+{
+	struct pci_dev *gpu;
+
+	if (PCI_FUNC(hda->devfn) != 1)
+		return;
+
+	gpu = pci_get_domain_bus_and_slot(pci_domain_nr(hda->bus),
+					  hda->bus->number,
+					  PCI_DEVFN(PCI_SLOT(hda->devfn), 0));
+	if (!gpu || (gpu->class >> 16) != PCI_BASE_CLASS_DISPLAY) {
+		pci_dev_put(gpu);
+		return;
+	}
+
+	if (!device_link_add(&hda->dev, &gpu->dev,
+			     DL_FLAG_STATELESS | DL_FLAG_PM_RUNTIME))
+		pci_err(hda, "cannot link HDA to GPU %s\n", pci_name(gpu));
+
+	pm_runtime_allow(&hda->dev);
+	pci_dev_put(gpu);
+}
+DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_VENDOR_ID_ATI, PCI_ANY_ID,
+			      PCI_CLASS_MULTIMEDIA_HD_AUDIO, 8, quirk_gpu_hda);
+DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_VENDOR_ID_AMD, PCI_ANY_ID,
+			      PCI_CLASS_MULTIMEDIA_HD_AUDIO, 8, quirk_gpu_hda);
+DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_VENDOR_ID_NVIDIA, PCI_ANY_ID,
+			      PCI_CLASS_MULTIMEDIA_HD_AUDIO, 8, quirk_gpu_hda);