mac80211: Retry null data frame for power save.

Even if the null data frame is not acked by the AP, mac80211
goes into power save. This might lead to loss of frames
from the AP.
Prevent this by restarting dynamic_ps_timer when ack is not
received for null data frames.

Cc: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Vivek Natarajan <vnatarajan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 15 insertions, 2 deletions

diff --git a/net/mac80211/status.c b/net/mac80211/status.c
index e57ad6b1d7ea..ded98730c111 100644
--- a/net/mac80211/status.c
+++ b/net/mac80211/status.c
@@ -188,6 +188,7 @@ void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb)
         rcu_read_lock();
 
         sband = local->hw.wiphy->bands[info->band];
+        fc = hdr->frame_control;
 
         for_each_sta_info(local, hdr->addr1, sta, tmp) {
                 /* skip wrong virtual interface */
@@ -205,8 +206,6 @@ void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb)
                         return;
                 }
 
-                fc = hdr->frame_control;
-
                 if ((info->flags & IEEE80211_TX_STAT_AMPDU_NO_BACK) &&
                     (ieee80211_is_data_qos(fc))) {
                         u16 tid, ssn;
@@ -275,6 +274,20 @@ void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb)
                         local->dot11FailedCount++;
         }
 
+        if (ieee80211_is_nullfunc(fc) && ieee80211_has_pm(fc) &&
+            (local->hw.flags & IEEE80211_HW_REPORTS_TX_ACK_STATUS) &&
+            !(info->flags & IEEE80211_TX_CTL_INJECTED) &&
+            local->ps_sdata && !(local->scanning)) {
+                if (info->flags & IEEE80211_TX_STAT_ACK) {
+                        local->ps_sdata->u.mgd.flags |=
+                                        IEEE80211_STA_NULLFUNC_ACKED;
+                        ieee80211_queue_work(&local->hw,
+                                        &local->dynamic_ps_enable_work);
+                } else
+                        mod_timer(&local->dynamic_ps_timer, jiffies +
+                                        msecs_to_jiffies(10));
+        }
+
         /* this was a transmitted frame, but now we want to reuse it */
         skb_orphan(skb);