ACPI / PM: Do not power manage devices in unknown initial states (b3785492) · Commits · 戴 / test

In general, for ACPI device power management to work, the initial power states of devices must be known (otherwise, we wouldn't be able to keep track of power resources, for example). Hence, if it is impossible to determine the initial ACPI power states of some devices, they can't be regarded as power-manageable using ACPI. For this reason, modify acpi_bus_get_power_flags() to clear the power_manageable flag if acpi_bus_init_power() fails and add some extra fallback code to acpi_bus_init_power() to cover broken BIOSes that provide _PS0/_PS3 without _PSC for some devices. Verified to work on my HP nx6325 that has this problem. Signed-off-by:

Rafael J. Wysocki <rafael.j.wysocki@intel.com> Tested-by:

Peter Wu <lekensteyn@gmail.com>

drivers/acpi/device_pm.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -330,6 +330,12 @@ int acpi_bus_init_power(struct acpi_device *device)
		result = acpi_dev_pm_explicit_set(device, state);
		if (result)
		return result;
		} else if (state == ACPI_STATE_UNKNOWN) {
		/* No power resources and missing _PSC? Try to force D0. */
		state = ACPI_STATE_D0;
		result = acpi_dev_pm_explicit_set(device, state);
		if (result)
		return result;
		}
		device->power.state = state;
		return 0;

drivers/acpi/scan.c

+4 −1

Original line number	Diff line number	Diff line
		@@ -1180,7 +1180,10 @@ static void acpi_bus_get_power_flags(struct acpi_device *device)
		device->power.flags.power_resources)
		device->power.states[ACPI_STATE_D3_COLD].flags.os_accessible = 1;

		acpi_bus_init_power(device);
		if (acpi_bus_init_power(device)) {
		acpi_free_power_resources_lists(device);
		device->flags.power_manageable = 0;
		}
		}

		static void acpi_bus_get_flags(struct acpi_device *device)

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