Commit 4d6035f9 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

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

Revert commit 4514d991 ("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: default avatarMichael <phyre@rogers.com>
Reported-by: default avatarSalvatore Bonaccorso <carnil@debian.org>
Fixes: 4514d991 ("PCI: PM: Do not read power state in pci_enable_device_flags()")
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 13311e74

drivers/pci/pci.c

+13 −3
Original line number Diff line number Diff line
@@ -1900,11 +1900,21 @@ 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);