In order to have better power management for Thunderbolt PCIe chains,
Windows enables power management for native PCIe hotplug ports if there is
the following ACPI _DSD attached to the root port:
Name (_DSD, Package () {
ToUUID ("
6211e2c0-58a3-4af3-90e1-
927a4e0c55a4"),
Package () {
Package () {"HotPlugSupportInD3", 1}
}
})
This is also documented in:
https://docs.microsoft.com/en-us/windows-hardware/drivers/pci/dsd-for-pcie-root-ports#identifying-pcie-root-ports-supporting-hot-plug-in-d3
Do the same in Linux by introducing new firmware PM callback
(->bridge_d3()) and then implement it for ACPI based systems so that the
above property is checked.
There is one catch, though. The initial pci_dev->bridge_d3 is set before
the root port has ACPI companion bound (the device is not added to the PCI
bus either) so we need to look up the ACPI companion manually in that case
in acpi_pci_bridge_d3().
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
/* ACPI _DSD device properties GUID: daffd814-6eba-4d8c-8a91-bc9bbf4aa301 */
GUID_INIT(0xdaffd814, 0x6eba, 0x4d8c,
0x8a, 0x91, 0xbc, 0x9b, 0xbf, 0x4a, 0xa3, 0x01),
/* ACPI _DSD device properties GUID: daffd814-6eba-4d8c-8a91-bc9bbf4aa301 */
GUID_INIT(0xdaffd814, 0x6eba, 0x4d8c,
0x8a, 0x91, 0xbc, 0x9b, 0xbf, 0x4a, 0xa3, 0x01),
+ /* Hotplug in D3 GUID: 6211e2c0-58a3-4af3-90e1-927a4e0c55a4 */
+ GUID_INIT(0x6211e2c0, 0x58a3, 0x4af3,
+ 0x90, 0xe1, 0x92, 0x7a, 0x4e, 0x0c, 0x55, 0xa4),
};
static const guid_t ads_guid =
};
static const guid_t ads_guid =
return PCI_POWER_ERROR;
}
return PCI_POWER_ERROR;
}
+static struct acpi_device *acpi_pci_find_companion(struct device *dev);
+
+static bool acpi_pci_bridge_d3(struct pci_dev *dev)
+{
+ const struct fwnode_handle *fwnode;
+ struct acpi_device *adev;
+ struct pci_dev *root;
+ u8 val;
+
+ if (!dev->is_hotplug_bridge)
+ return false;
+
+ /*
+ * Look for a special _DSD property for the root port and if it
+ * is set we know the hierarchy behind it supports D3 just fine.
+ */
+ root = pci_find_pcie_root_port(dev);
+ if (!root)
+ return false;
+
+ adev = ACPI_COMPANION(&root->dev);
+ if (root == dev) {
+ /*
+ * It is possible that the ACPI companion is not yet bound
+ * for the root port so look it up manually here.
+ */
+ if (!adev && !pci_dev_is_added(root))
+ adev = acpi_pci_find_companion(&root->dev);
+ }
+
+ if (!adev)
+ return false;
+
+ fwnode = acpi_fwnode_handle(adev);
+ if (fwnode_property_read_u8(fwnode, "HotPlugSupportInD3", &val))
+ return false;
+
+ return val == 1;
+}
+
static bool acpi_pci_power_manageable(struct pci_dev *dev)
{
struct acpi_device *adev = ACPI_COMPANION(&dev->dev);
static bool acpi_pci_power_manageable(struct pci_dev *dev)
{
struct acpi_device *adev = ACPI_COMPANION(&dev->dev);
}
static const struct pci_platform_pm_ops acpi_pci_platform_pm = {
}
static const struct pci_platform_pm_ops acpi_pci_platform_pm = {
+ .bridge_d3 = acpi_pci_bridge_d3,
.is_manageable = acpi_pci_power_manageable,
.set_state = acpi_pci_set_power_state,
.get_state = acpi_pci_get_power_state,
.is_manageable = acpi_pci_power_manageable,
.set_state = acpi_pci_set_power_state,
.get_state = acpi_pci_get_power_state,
return pci_platform_pm ? pci_platform_pm->need_resume(dev) : false;
}
return pci_platform_pm ? pci_platform_pm->need_resume(dev) : false;
}
+static inline bool platform_pci_bridge_d3(struct pci_dev *dev)
+{
+ return pci_platform_pm ? pci_platform_pm->bridge_d3(dev) : false;
+}
+
/**
* pci_raw_set_power_state - Use PCI PM registers to set the power state of
* given PCI device
/**
* pci_raw_set_power_state - Use PCI PM registers to set the power state of
* given PCI device
if (bridge->is_thunderbolt)
return true;
if (bridge->is_thunderbolt)
return true;
+ /* Platform might know better if the bridge supports D3 */
+ if (platform_pci_bridge_d3(bridge))
+ return true;
+
/*
* Hotplug ports handled natively by the OS were not validated
* by vendors for runtime D3 at least until 2018 because there
/*
* Hotplug ports handled natively by the OS were not validated
* by vendors for runtime D3 at least until 2018 because there
/**
* struct pci_platform_pm_ops - Firmware PM callbacks
*
/**
* struct pci_platform_pm_ops - Firmware PM callbacks
*
+ * @bridge_d3: Does the bridge allow entering into D3
+ *
* @is_manageable: returns 'true' if given device is power manageable by the
* platform firmware
*
* @is_manageable: returns 'true' if given device is power manageable by the
* platform firmware
*
* these callbacks are mandatory.
*/
struct pci_platform_pm_ops {
* these callbacks are mandatory.
*/
struct pci_platform_pm_ops {
+ bool (*bridge_d3)(struct pci_dev *dev);
bool (*is_manageable)(struct pci_dev *dev);
int (*set_state)(struct pci_dev *dev, pci_power_t state);
pci_power_t (*get_state)(struct pci_dev *dev);
bool (*is_manageable)(struct pci_dev *dev);
int (*set_state)(struct pci_dev *dev, pci_power_t state);
pci_power_t (*get_state)(struct pci_dev *dev);