[PATCH 1/1] igb: Fix an issue that PME is not enabled during runtime suspend

[Kai-Heng Feng]

BugLink: https://bugs.launchpad.net/bugs/1806818

I210 ethernet card doesn't wakeup when a cable gets plugged. It's
because its PME is not set.

Since commit 42eca2302146 ("PCI: Don't touch card regs after runtime
suspend D3"), if the PCI state is saved, pci_pm_runtime_suspend() stops
calling pci_finish_runtime_suspend(), which enables the PCI PME.

To fix the issue, let's not to save PCI states when it's runtime
suspend, to let the PCI subsytem enables PME.

Fixes: 42eca2302146 ("PCI: Don't touch card regs after runtime suspend D3")
Signed-off-by: Kai-Heng Feng <kai.heng.feng at canonical.com>
(cherry picked from commit c881c486761fd093d104fa86e373e504aa60f35e git://git.kernel.org/pub/scm/linux/kernel/git/jkirsher/next-queue.git dev-queue)
Signed-off-by: Kai-Heng Feng <kai.heng.feng at canonical.com>
---
 drivers/net/ethernet/intel/igb/igb_main.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index 0796cef96fa3..ffaa6e031632 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -8770,9 +8770,11 @@ static int __igb_shutdown(struct pci_dev *pdev, bool *enable_wake,
 	rtnl_unlock();
 
 #ifdef CONFIG_PM
-	retval = pci_save_state(pdev);
-	if (retval)
-		return retval;
+	if (!runtime) {
+		retval = pci_save_state(pdev);
+		if (retval)
+			return retval;
+	}
 #endif
 
 	status = rd32(E1000_STATUS);
-- 
2.17.1