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Revert "PCI: PM: Do not read power state in pci_enable_device_flags()"

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[ Upstream commit 4d6035f9bf4ea12776322746a216e856dfe46698 ]

Revert commit 4514d991d992 ("PCI: PM: Do not read power state in
pci_enable_device_flags()") that is reported to cause PCI device
initialization issues on some systems.

BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=213481
Link: https://lore.kernel.org/linux-acpi/YNDoGICcg0V8HhpQ@eldamar.lan
Reported-by: Michael <phyre@rogers.com>
Reported-by: Salvatore Bonaccorso <carnil@debian.org>
Fixes: 4514d991d992 ("PCI: PM: Do not read power state in pci_enable_device_flags()")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Rafael J. Wysocki 2021-06-22 17:35:18 +02:00 committed by Sasha Levin
parent 4b06ebab4a
commit f11f9ff8a7
1 changed files with 13 additions and 3 deletions
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16
drivers/pci/pci.c
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@ -1874,11 +1874,21 @@ static int pci_enable_device_flags(struct pci_dev *dev, unsigned long flags)
int err;
int i, bars = 0;
if (atomic_inc_return(&dev->enable_cnt) > 1) {
pci_update_current_state(dev, dev->current_state);
return 0; /* already enabled */
/*
* Power state could be unknown at this point, either due to a fresh
* boot or a device removal call. So get the current power state
* so that things like MSI message writing will behave as expected
* (e.g. if the device really is in D0 at enable time).
*/
if (dev->pm_cap) {
u16 pmcsr;
pci_read_config_word(dev, dev->pm_cap + PCI_PM_CTRL, &pmcsr);
dev->current_state = (pmcsr & PCI_PM_CTRL_STATE_MASK);
}
if (atomic_inc_return(&dev->enable_cnt) > 1)
return 0; /* already enabled */
bridge = pci_upstream_bridge(dev);
if (bridge)
pci_enable_bridge(bridge);