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PCI/PM: Rearrange pci_set_power_state()

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The part of pci_set_power_state() related to transitions into
low-power states is unnecessary convoluted, so clearly divide it
into the D3cold special case and the general case covering all of
the other states.

Also fix a potential issue with calling pci_bus_set_current_state()
to set the current state of all devices on the subordinate bus to
D3cold without checking if the power state of the parent bridge has
really changed to D3cold.

Link: https://lore.kernel.org/r/2139440.Mh6RI2rZIc@kreacher
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
This commit is contained in:
Rafael J. Wysocki 2022-05-05 20:16:50 +02:00 committed by Bjorn Helgaas
parent 0aacdc9574
commit 3cc2a2b270
1 changed files with 17 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
drivers/pci/pci.c
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@ -1446,19 +1446,25 @@ int pci_set_power_state(struct pci_dev *dev, pci_power_t state)
if (state >= PCI_D3hot && (dev->dev_flags & PCI_DEV_FLAGS_NO_D3))
return 0;
/*
* To put device in D3cold, we put device into D3hot in native
* way, then put device into D3cold with platform ops
*/
error = pci_set_low_power_state(dev, state > PCI_D3hot ?
PCI_D3hot : state);
if (state == PCI_D3cold) {
/*
* To put the device in D3cold, put it into D3hot in the native
* way, then put it into D3cold using platform ops.
*/
error = pci_set_low_power_state(dev, PCI_D3hot);
if (pci_platform_power_transition(dev, state))
return error;
if (pci_platform_power_transition(dev, PCI_D3cold))
return error;
/* Powering off a bridge may power off the whole hierarchy */
if (state == PCI_D3cold)
pci_bus_set_current_state(dev->subordinate, PCI_D3cold);
/* Powering off a bridge may power off the whole hierarchy */
if (dev->current_state == PCI_D3cold)
pci_bus_set_current_state(dev->subordinate, PCI_D3cold);
} else {
error = pci_set_low_power_state(dev, state);
if (pci_platform_power_transition(dev, state))
return error;
}
return 0;
}