1 files changed, 40 insertions, 13 deletions

diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
index 052a611081ec..a05350a4e49c 100644
--- a/drivers/pci/pci-acpi.c
+++ b/drivers/pci/pci-acpi.c
@@ -1043,6 +1043,16 @@ bool acpi_pci_bridge_d3(struct pci_dev *dev)
 	return false;
 }
 
+static void acpi_pci_config_space_access(struct pci_dev *dev, bool enable)
+{
+	int val = enable ? ACPI_REG_CONNECT : ACPI_REG_DISCONNECT;
+	int ret = acpi_evaluate_reg(ACPI_HANDLE(&dev->dev),
+				    ACPI_ADR_SPACE_PCI_CONFIG, val);
+	if (ret)
+		pci_dbg(dev, "ACPI _REG %s evaluation failed (%d)\n",
+			enable ? "connect" : "disconnect", ret);
+}
+
 int acpi_pci_set_power_state(struct pci_dev *dev, pci_power_t state)
 {
 	struct acpi_device *adev = ACPI_COMPANION(&dev->dev);
@@ -1053,32 +1063,49 @@ int acpi_pci_set_power_state(struct pci_dev *dev, pci_power_t state)
 		[PCI_D3hot] = ACPI_STATE_D3_HOT,
 		[PCI_D3cold] = ACPI_STATE_D3_COLD,
 	};
-	int error = -EINVAL;
+	int error;
 
 	/* If the ACPI device has _EJ0, ignore the device */
 	if (!adev || acpi_has_method(adev->handle, "_EJ0"))
 		return -ENODEV;
 
 	switch (state) {
-	case PCI_D3cold:
-		if (dev_pm_qos_flags(&dev->dev, PM_QOS_FLAG_NO_POWER_OFF) ==
-				PM_QOS_FLAGS_ALL) {
-			error = -EBUSY;
-			break;
-		}
-		fallthrough;
 	case PCI_D0:
 	case PCI_D1:
 	case PCI_D2:
 	case PCI_D3hot:
-		error = acpi_device_set_power(adev, state_conv[state]);
+	case PCI_D3cold:
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (state == PCI_D3cold) {
+		if (dev_pm_qos_flags(&dev->dev, PM_QOS_FLAG_NO_POWER_OFF) ==
+				PM_QOS_FLAGS_ALL)
+			return -EBUSY;
+
+		/* Notify AML lack of PCI config space availability */
+		acpi_pci_config_space_access(dev, false);
 	}
 
-	if (!error)
-		pci_dbg(dev, "power state changed by ACPI to %s\n",
-		        acpi_power_state_string(adev->power.state));
+	error = acpi_device_set_power(adev, state_conv[state]);
+	if (error)
+		return error;
 
-	return error;
+	pci_dbg(dev, "power state changed by ACPI to %s\n",
+	        acpi_power_state_string(adev->power.state));
+
+	/*
+	 * Notify AML of PCI config space availability.  Config space is
+	 * accessible in all states except D3cold; the only transitions
+	 * that change availability are transitions to D3cold and from
+	 * D3cold to D0.
+	 */
+	if (state == PCI_D0)
+		acpi_pci_config_space_access(dev, true);
+
+	return 0;
 }
 
 pci_power_t acpi_pci_get_power_state(struct pci_dev *dev)