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authorBjorn Helgaas <bhelgaas@google.com>2023-02-22 22:47:26 +0300
committerBjorn Helgaas <bhelgaas@google.com>2023-02-22 22:47:26 +0300
commit08a67024a0b4a18b2fad8d5b3670f02e9b24ebfb (patch)
tree06c47e0a9cc9ca433c2e6af778659219e28dd4ec /drivers/pci
parent7260675a52a67f3c44036306bf25f6947c294a02 (diff)
parent8133844a8f2434be9576850c6978179d7cca5c81 (diff)
downloadlinux-08a67024a0b4a18b2fad8d5b3670f02e9b24ebfb.tar.xz
Merge branch 'pci/pm'
- Account for _S0W when deciding whether to put bridges in D3 to avoid missing hotplug events (Rafael J. Wysocki) * pci/pm: PCI/ACPI: Account for _S0W of the target bridge in acpi_pci_bridge_d3()
Diffstat (limited to 'drivers/pci')
-rw-r--r--drivers/pci/pci-acpi.c45
1 files changed, 31 insertions, 14 deletions
diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
index 068d6745bf98..052a611081ec 100644
--- a/drivers/pci/pci-acpi.c
+++ b/drivers/pci/pci-acpi.c
@@ -976,24 +976,41 @@ bool acpi_pci_power_manageable(struct pci_dev *dev)
bool acpi_pci_bridge_d3(struct pci_dev *dev)
{
struct pci_dev *rpdev;
- struct acpi_device *adev;
- acpi_status status;
- unsigned long long state;
+ struct acpi_device *adev, *rpadev;
const union acpi_object *obj;
if (acpi_pci_disabled || !dev->is_hotplug_bridge)
return false;
- /* Assume D3 support if the bridge is power-manageable by ACPI. */
- if (acpi_pci_power_manageable(dev))
- return true;
+ adev = ACPI_COMPANION(&dev->dev);
+ if (adev) {
+ /*
+ * If the bridge has _S0W, whether or not it can go into D3
+ * depends on what is returned by that object. In particular,
+ * if the power state returned by _S0W is D2 or shallower,
+ * entering D3 should not be allowed.
+ */
+ if (acpi_dev_power_state_for_wake(adev) <= ACPI_STATE_D2)
+ return false;
+
+ /*
+ * Otherwise, assume that the bridge can enter D3 so long as it
+ * is power-manageable via ACPI.
+ */
+ if (acpi_device_power_manageable(adev))
+ return true;
+ }
rpdev = pcie_find_root_port(dev);
if (!rpdev)
return false;
- adev = ACPI_COMPANION(&rpdev->dev);
- if (!adev)
+ if (rpdev == dev)
+ rpadev = adev;
+ else
+ rpadev = ACPI_COMPANION(&rpdev->dev);
+
+ if (!rpadev)
return false;
/*
@@ -1001,15 +1018,15 @@ bool acpi_pci_bridge_d3(struct pci_dev *dev)
* doesn't supply a wakeup GPE via _PRW, it cannot signal hotplug
* events from low-power states including D3hot and D3cold.
*/
- if (!adev->wakeup.flags.valid)
+ if (!rpadev->wakeup.flags.valid)
return false;
/*
- * If the Root Port cannot wake itself from D3hot or D3cold, we
- * can't use D3.
+ * In the bridge-below-a-Root-Port case, evaluate _S0W for the Root Port
+ * to verify whether or not it can signal wakeup from D3.
*/
- status = acpi_evaluate_integer(adev->handle, "_S0W", NULL, &state);
- if (ACPI_SUCCESS(status) && state < ACPI_STATE_D3_HOT)
+ if (rpadev != adev &&
+ acpi_dev_power_state_for_wake(rpadev) <= ACPI_STATE_D2)
return false;
/*
@@ -1018,7 +1035,7 @@ bool acpi_pci_bridge_d3(struct pci_dev *dev)
* bridges *below* that Root Port can also signal hotplug events
* while in D3.
*/
- if (!acpi_dev_get_property(adev, "HotPlugSupportInD3",
+ if (!acpi_dev_get_property(rpadev, "HotPlugSupportInD3",
ACPI_TYPE_INTEGER, &obj) &&
obj->integer.value == 1)
return true;