PCI PM: Make pci_set_power_state() handle devices with no PM support (4a865905) · Commits · 戴 / test

There is a problem with PCI devices without any PM support (either native or through the platform) that pci_set_power_state() always returns error code for them, even if they are being put into D0. However, such devices are always in D0, so pci_set_power_state() should return success when attempting to put such a device into D0. It also should update the current_state field for these devices as appropriate. This modification is necessary so that the standard configuration registers of these devices are successfully restored by pci_restore_standard_config() during the "early" phase of resume. In addition, pci_set_power_state() should check the value of current_state before calling the platform to change the power state of the device to avoid doing that unnecessarily. Signed-off-by:

Rafael J. Wysocki <rjw@sisk.pl> Acked-by:

Ingo Molnar <mingo@elte.hu> Acked-by:

Jesse Barnes <jbarnes@virtuousgeek.org>

drivers/pci/pci.c

+12 −6

Original line number	Diff line number	Diff line
		@@ -439,6 +439,10 @@ static int pci_raw_set_power_state(struct pci_dev *dev, pci_power_t state)
		u16 pmcsr;
		bool need_restore = false;

		/* Check if we're already there */
		if (dev->current_state == state)
		return 0;

		if (!dev->pm_cap)
		return -EIO;

		@@ -449,10 +453,7 @@ static int pci_raw_set_power_state(struct pci_dev *dev, pci_power_t state)
		* Can enter D0 from any state, but if we can only go deeper
		* to sleep if we're already in a low power state
		*/
		if (dev->current_state == state) {
		/* we're already there */
		return 0;
		} else if (state != PCI_D0 && dev->current_state <= PCI_D3cold
		if (state != PCI_D0 && dev->current_state <= PCI_D3cold
		&& dev->current_state > state) {
		dev_err(&dev->dev, "invalid power transition "
		"(from state %d to %d)\n", dev->current_state, state);
		@@ -570,12 +571,17 @@ int pci_set_power_state(struct pci_dev *dev, pci_power_t state)
		*/
		return 0;

		if (state == PCI_D0 && platform_pci_power_manageable(dev)) {
		/* Check if we're already there */
		if (dev->current_state == state)
		return 0;

		if (state == PCI_D0) {
		/*
		* Allow the platform to change the state, for example via ACPI
		* _PR0, _PS0 and some such, but do not trust it.
		*/
		int ret = platform_pci_set_power_state(dev, PCI_D0);
		int ret = platform_pci_power_manageable(dev) ?
		platform_pci_set_power_state(dev, PCI_D0) : 0;
		if (!ret)
		pci_update_current_state(dev, PCI_D0);
		}

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