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PCI/PM: Power up all devices during runtime resume

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Currently, endpoint devices may not be powered up entirely during runtime
resume that follows a D3hot -> D0 transition of the parent bridge.

Namely, even if the power state of an endpoint device, as indicated by its
PCI_PM_CTRL register, is D0 after powering up its parent bridge, it may be
still necessary to bring its ACPI companion into D0 and that should be done
before accessing it.  However, the current code assumes that reading the
PCI_PM_CTRL register is sufficient to establish the endpoint device's power
state, which may lead to problems.

Address that by forcing a power-up of all PCI devices, including the
platform firmware part of it, during runtime resume.

Link: https://lore.kernel.org/linux-pm/11967527.O9o76ZdvQC@kreacher
Fixes: 5775b843a6 ("PCI: Restore config space on runtime resume despite being unbound")
Link: https://lore.kernel.org/r/2652115.mvXUDI8C0e@kreacher
Reported-by: Abhishek Sahu <abhsahu@nvidia.com>
Tested-by: Abhishek Sahu <abhsahu@nvidia.com>
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 2022-04-08 20:29:01 +02:00 committed by Bjorn Helgaas
parent 18a94192e2
commit 9a6058312e
1 changed files with 1 additions and 1 deletions
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2
drivers/pci/pci-driver.c
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@ -1317,7 +1317,7 @@ static int pci_pm_runtime_resume(struct device *dev)
* to a driver because although we left it in D0, it may have gone to
* D3cold when the bridge above it runtime suspended.
*/
pci_restore_standard_config(pci_dev);
pci_pm_default_resume_early(pci_dev);
if (!pci_dev->driver)
return 0;