--- /dev/null
+From 5233ce4f073198c7cfce4483f72254448bde2239 Mon Sep 17 00:00:00 2001
+From: Sasha Levin <sashal@kernel.org>
+Date: Tue, 22 Jun 2021 17:35:18 +0200
+Subject: Revert "PCI: PM: Do not read power state in
+ pci_enable_device_flags()"
+
+From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
+
+[ 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>
+---
+ drivers/pci/pci.c | 16 +++++++++++++---
+ 1 file changed, 13 insertions(+), 3 deletions(-)
+
+diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
+index 1993e5e28ea7..c847b5554db6 100644
+--- a/drivers/pci/pci.c
++++ b/drivers/pci/pci.c
+@@ -1378,11 +1378,21 @@ 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);
+--
+2.30.2
+