[PATCH 4.4 339/342] iwlwifi: dvm: fix WoWLAN

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

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

From: Emmanuel Grumbach <emmanuel.grumbach@xxxxxxxxx>

commit a1cdb1c59c8c203de2731fc6910598ed19c97e41 upstream.

My commit below introduced a mutex in the transport to
prevent concurrent operations. To do so, it added a flag
(is_down) to make sure the transport is in the right state.
This uncoverred an bug that didn't cause any harm until
now: iwldvm calls stop_device and then starts the firmware
without calling start_hw in between. While this flow is
fine from the device configuration point of view (register,
etc...), it is now forbidden by the new is_down flag.
This led to this error to appear:
iwlwifi 0000:05:00.0: Can't start_fw since the HW hasn't been started
and the suspend would fail.

This fixes:
https://bugzilla.kernel.org/show_bug.cgi?id=109591

Reported-by: Bogdan Bogush <bogdan.s.bogush@xxxxxxxxx>
Fixes=fa9f3281cbb1 ("iwlwifi: pcie: lock start_hw / start_fw / stop_device")
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/net/wireless/iwlwifi/dvm/lib.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/net/wireless/iwlwifi/dvm/lib.c
+++ b/drivers/net/wireless/iwlwifi/dvm/lib.c
@@ -1154,6 +1154,9 @@ int iwlagn_suspend(struct iwl_priv *priv
 
 	priv->ucode_loaded = false;
 	iwl_trans_stop_device(priv->trans);
+	ret = iwl_trans_start_hw(priv->trans);
+	if (ret)
+		goto out;
 
 	priv->wowlan = true;