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PCI/PM: Do not restore BARs if device is not in D0

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Do not attempt to restore the device's BARs in
pci_set_full_power_state() if the actual current
power state of the device is not D0.

Link: https://lore.kernel.org/r/1849718.CQOukoFCf9@kreacher
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
This commit is contained in:
Rafael J. Wysocki 2022-05-05 20:14:24 +02:00 committed by Bjorn Helgaas
parent e200904b27
commit 0ce74a3b9c
1 changed files with 16 additions and 16 deletions
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32
drivers/pci/pci.c
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@ -1273,25 +1273,25 @@ static int pci_set_full_power_state(struct pci_dev *dev)
pci_read_config_word(dev, dev->pm_cap + PCI_PM_CTRL, &pmcsr);
dev->current_state = pmcsr & PCI_PM_CTRL_STATE_MASK;
if (dev->current_state != PCI_D0)
if (dev->current_state != PCI_D0) {
pci_info_ratelimited(dev, "Refused to change power state from %s to D0\n",
pci_power_name(dev->current_state));
/*
* According to section 5.4.1 of the "PCI BUS POWER MANAGEMENT
* INTERFACE SPECIFICATION, REV. 1.2", a device transitioning
* from D3hot to D0 _may_ perform an internal reset, thereby
* going to "D0 Uninitialized" rather than "D0 Initialized".
* For example, at least some versions of the 3c905B and the
* 3c556B exhibit this behaviour.
*
* At least some laptop BIOSen (e.g. the Thinkpad T21) leave
* devices in a D3hot state at boot. Consequently, we need to
* restore at least the BARs so that the device will be
* accessible to its driver.
*/
if (ret > 0)
} else if (ret > 0) {
/*
* According to section 5.4.1 of the "PCI BUS POWER MANAGEMENT
* INTERFACE SPECIFICATION, REV. 1.2", a device transitioning
* from D3hot to D0 _may_ perform an internal reset, thereby
* going to "D0 Uninitialized" rather than "D0 Initialized".
* For example, at least some versions of the 3c905B and the
* 3c556B exhibit this behaviour.
*
* At least some laptop BIOSen (e.g. the Thinkpad T21) leave
* devices in a D3hot state at boot. Consequently, we need to
* restore at least the BARs so that the device will be
* accessible to its driver.
*/
pci_restore_bars(dev);
}
if (dev->bus->self)
pcie_aspm_pm_state_change(dev->bus->self);