PCI: PM: Avoid forcing PCI_D0 for wakeup reasons inconsistently

stable inclusion
from stable-5.10.65
commit 3890c6e1da3146545f9c34611fc94672667a0ce5
bugzilla: 182361 https://gitee.com/openeuler/kernel/issues/I4EH3U

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=3890c6e1da3146545f9c34611fc94672667a0ce5

--------------------------------

[ Upstream commit da9f2150 ]

It is inconsistent to return PCI_D0 from pci_target_state() instead
of the original target state if 'wakeup' is true and the device
cannot signal PME from D0.

This only happens when the device cannot signal PME from the original
target state and any shallower power states (including D0) and that
case is effectively equivalent to the one in which PME singaling is
not supported at all.  Since the original target state is returned in
the latter case, make the function do that in the former one too.

Link: https://lore.kernel.org/linux-pm/3149540.aeNJFYEL58@kreacher/
Fixes: 666ff6f8 ("PCI/PM: Avoid using device_may_wakeup() for runtime PM")
Reported-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Reported-by: NUtkarsh H Patel <utkarsh.h.patel@intel.com>
Reported-by: NKoba Ko <koba.ko@canonical.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Tested-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Acked-by: NWeilong Chen <chenweilong@huawei.com>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/pci/pci.c

@@ -2573,16 +2573,20 @@ static pci_power_t pci_target_state(struct pci_dev *dev, bool wakeup)
 	if (dev->current_state == PCI_D3cold)
 		target_state = PCI_D3cold;
 
-	if (wakeup) {
+	if (wakeup && dev->pme_support) {
+		pci_power_t state = target_state;
+
 		/*
 		 * Find the deepest state from which the device can generate
 		 * PME#.
 		 */
-		if (dev->pme_support) {
-			while (target_state
-			      && !(dev->pme_support & (1 << target_state)))
-				target_state--;
-		}
+		while (state && !(dev->pme_support & (1 << state)))
+			state--;
+
+		if (state)
+			return state;
+		else if (dev->pme_support & 1)
+			return PCI_D0;
 	}
 
 	return target_state;