@@ -293,6 +293,29 @@ static void lpi_device_get_constraints(void)
ACPI_FREE(out_obj);
}
+/**
+ * acpi_get_lps0_constraint - get any LPS0 constraint for a device
+ * @dev: device to get constraint for
+ *
+ * If a constraint has been specified in the _DSM method for the device,
+ * and the constraint is enabled return it. If the constraint is disabled,
+ * return 0. Otherwise, return -ENODEV.
+ */
+int acpi_get_lps0_constraint(struct device *dev)
+{
+ int i;
+
+ for (i = 0; i < lpi_constraints_table_size; ++i) {
+ if (!device_match_acpi_handle(dev, lpi_constraints_table[i].handle))
+ continue;
+ if (!lpi_constraints_table[i].enabled)
+ return 0;
+ return lpi_constraints_table[i].min_dstate;
+ }
+
+ return -ENODEV;
+}
+
static void lpi_check_constraints(void)
{
int i;
@@ -1043,6 +1043,28 @@ bool acpi_pci_bridge_d3(struct pci_dev *dev)
return false;
}
+/**
+ * acpi_pci_device_constraint - determine if the platform has a contraint for the device
+ * @dev: PCI device to check
+ * @result (out): the constraint specified by the platform
+ *
+ * If the platform has specified a constraint for a device, this function will
+ * return 0 and set @result to the constraint.
+ * Otherwise, it will return an error code.
+ */
+int acpi_pci_device_constraint(struct pci_dev *dev, int *result)
+{
+ int constraint;
+
+ constraint = acpi_get_lps0_constraint(&dev->dev);
+ pci_dbg(dev, "ACPI device constraint: %d\n", constraint);
+ if (constraint < 0)
+ return constraint;
+ *result = constraint;
+
+ return 0;
+}
+
static void acpi_pci_config_space_access(struct pci_dev *dev, bool enable)
{
int val = enable ? ACPI_REG_CONNECT : ACPI_REG_DISCONNECT;
@@ -1082,6 +1082,14 @@ static inline bool platform_pci_bridge_d3(struct pci_dev *dev)
return acpi_pci_bridge_d3(dev);
}
+static inline int platform_get_constraint(struct pci_dev *dev, int *result)
+{
+ if (pci_use_mid_pm())
+ return -ENODEV;
+
+ return acpi_pci_device_constraint(dev, result);
+}
+
/**
* pci_update_current_state - Read power state of given device and cache it
* @dev: PCI device to handle.
@@ -2671,6 +2679,8 @@ EXPORT_SYMBOL(pci_wake_from_d3);
*/
static pci_power_t pci_target_state(struct pci_dev *dev, bool wakeup)
{
+ int val;
+
if (platform_pci_power_manageable(dev)) {
/*
* Call the platform to find the target state for the device.
@@ -2691,6 +2701,10 @@ static pci_power_t pci_target_state(struct pci_dev *dev, bool wakeup)
return state;
}
+ /* if platform indicates in a device constraint, use it */
+ if (!platform_get_constraint(dev, &val))
+ return val;
+
/*
* If the device is in D3cold even though it's not power-manageable by
* the platform, it may have been powered down by non-standard means.
@@ -707,6 +707,7 @@ void pci_set_acpi_fwnode(struct pci_dev *dev);
int pci_dev_acpi_reset(struct pci_dev *dev, bool probe);
bool acpi_pci_power_manageable(struct pci_dev *dev);
bool acpi_pci_bridge_d3(struct pci_dev *dev);
+int acpi_pci_device_constraint(struct pci_dev *dev, int *result);
int acpi_pci_set_power_state(struct pci_dev *dev, pci_power_t state);
pci_power_t acpi_pci_get_power_state(struct pci_dev *dev);
void acpi_pci_refresh_power_state(struct pci_dev *dev);
@@ -731,6 +732,10 @@ static inline bool acpi_pci_bridge_d3(struct pci_dev *dev)
{
return false;
}
+static inline int acpi_pci_device_constraint(struct pci_dev *dev, int *result)
+{
+ return -ENODEV;
+}
static inline int acpi_pci_set_power_state(struct pci_dev *dev, pci_power_t state)
{
return -ENODEV;
@@ -1100,7 +1100,7 @@ void acpi_os_set_prepare_extended_sleep(int (*func)(u8 sleep_state,
acpi_status acpi_os_prepare_extended_sleep(u8 sleep_state,
u32 val_a, u32 val_b);
-#ifdef CONFIG_X86
+#if defined(CONFIG_ACPI_SLEEP) && defined(CONFIG_X86)
struct acpi_s2idle_dev_ops {
struct list_head list_node;
void (*prepare)(void);
@@ -1109,7 +1109,13 @@ struct acpi_s2idle_dev_ops {
};
int acpi_register_lps0_dev(struct acpi_s2idle_dev_ops *arg);
void acpi_unregister_lps0_dev(struct acpi_s2idle_dev_ops *arg);
-#endif /* CONFIG_X86 */
+int acpi_get_lps0_constraint(struct device *dev);
+#else
+static inline int acpi_get_lps0_constraint(struct device *dev)
+{
+ return false;
+}
+#endif /* CONFIG_ACPI_SLEEP && CONFIG_X86 */
#ifndef CONFIG_IA64
void arch_reserve_mem_area(acpi_physical_address addr, size_t size);
#else
Since commit 9d26d3a8f1b0 ("PCI: Put PCIe ports into D3 during suspend") PCIe ports from modern machines (>=2015) are allowed to be put into D3 by storing a value to the `bridge_d3` variable in the `struct pci_dev` structure. pci_power_manageable() uses this variable to indicate a PCIe port can enter D3. pci_pm_suspend_noirq() uses the return from pci_power_manageable() to decide whether to try to put a device into its target state for a sleep cycle via pci_prepare_to_sleep(). For devices that support D3, the target state is selected by this policy: 1. If platform_pci_power_manageable(): Use platform_pci_choose_state() 2. If the device is armed for wakeup: Select the deepest D-state that supports a PME. 3. Else: Use D3hot. Devices are considered power manageable by the platform when they have one or more objects described in the table in section 7.3 of the ACPI 6.5 specification. When devices are not considered power manageable; specs are ambiguous as to what should happen. In this situation Windows 11 leaves PCIe ports in D0 while Linux puts them into D3 due to the above mentioned commit. In Windows systems that support Modern Standby specify hardware pre-conditions for the SoC to achieve the lowest power state by device constraints in a SOC specific "Power Engine Plugin" (PEP) [2] [3]. They can be marked as disabled or enabled and when enabled can specify the minimum power state required for an ACPI device. When it is ambiguous what should happen, adjust the logic for pci_target_state() to check whether a device constraint is present and enabled. * If power manageable by ACPI use this to get to select target state * If a device constraint is present but disabled then choose D0 * If a device constraint is present and enabled then use it * If a device constraint is not present, then continue to existing logic (if marked for wakeup use deepest state that PME works) * If not marked for wakeup choose D3hot Link: https://uefi.org/specs/ACPI/6.5/07_Power_and_Performance_Mgmt.html#device-power-management-objects [1] Link: https://learn.microsoft.com/en-us/windows-hardware/design/device-experiences/platform-design-for-modern-standby#low-power-core-silicon-cpu-soc-dram [2] Link: https://uefi.org/sites/default/files/resources/Intel_ACPI_Low_Power_S0_Idle.pdf [3] Fixes: 9d26d3a8f1b0 ("PCI: Put PCIe ports into D3 during suspend") Reported-by: Iain Lane <iain@orangesquash.org.uk> Closes: https://forums.lenovo.com/t5/Ubuntu/Z13-can-t-resume-from-suspend-with-external-USB-keyboard/m-p/5217121 Signed-off-by: Mario Limonciello <mario.limonciello@amd.com> --- v8->v9: * Use device_match_acpi_handle instead * Move the logic to run at the state selection time * Small fixups suggested by Andy * Call from pci_target_state() instead v7->v8: * Use device constraints instead * Update commit message and links --- drivers/acpi/x86/s2idle.c | 23 +++++++++++++++++++++++ drivers/pci/pci-acpi.c | 22 ++++++++++++++++++++++ drivers/pci/pci.c | 14 ++++++++++++++ drivers/pci/pci.h | 5 +++++ include/linux/acpi.h | 10 ++++++++-- 5 files changed, 72 insertions(+), 2 deletions(-)