[PATCH net 3/3] igb: only allow runtime PM if the device can wake up

[Antonio Quartulli <antonio@mandelbit.com>]

igb lets the device be runtime suspended even if it can't signal a
wake-up from D3. Such a device doesn't notice the link coming back, so
the port stays down until it is resumed from user space.

Allow runtime PM only if pci_dev_run_wake() is true, as e1000e and
r8169 do. Devices that can't wake up no longer runtime suspend, even
with power/control set to auto.

Fixes: 749ab2cd1270 ("igb: add basic runtime PM support")
Cc: stable@vger.kernel.org
Closes: https://bugzilla.ipfire.org/show_bug.cgi?id=13562
Signed-off-by: Antonio Quartulli <antonio@mandelbit.com>
---
Note: igc may have the same issue: igc_probe() also allows runtime PM
regardless of pci_dev_run_wake(). We didn't have igc hardware to test a
fix with, so no igc patch is sent for now.

 drivers/net/ethernet/intel/igb/igb_main.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index 4d97399..59f59da 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -3677,7 +3677,11 @@ static int igb_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 
 	dev_pm_set_driver_flags(&pdev->dev, DPM_FLAG_NO_DIRECT_COMPLETE);
 
-	pm_runtime_put_noidle(&pdev->dev);
+	/* A device that can't wake up wouldn't notice the link coming back
+	 * while runtime suspended
+	 */
+	if (pci_dev_run_wake(pdev))
+		pm_runtime_put_noidle(&pdev->dev);
 	return 0;
 
 err_register:
@@ -3900,7 +3904,8 @@ static void igb_remove(struct pci_dev *pdev)
 	struct igb_adapter *adapter = netdev_priv(netdev);
 	struct e1000_hw *hw = &adapter->hw;
 
-	pm_runtime_get_noresume(&pdev->dev);
+	if (pci_dev_run_wake(pdev))
+		pm_runtime_get_noresume(&pdev->dev);
 #ifdef CONFIG_IGB_HWMON
 	igb_sysfs_exit(adapter);
 #endif
-- 
2.56.0