ath9k: fix processing of TX PS null data frames

When mac80211 was telling us to go into Powersave we listened
and immediately turned RX off. This meant hardware would not
see the ACKs from the AP we're associated with and hardware
we'd end up retransmiting the null data frame in a loop
helplessly.

Fix this by keeping track of the transmitted nullfunc frames
and only when we are sure the AP has sent back an ACK do we
go ahead and shut RX off.

Signed-off-by: Vasanthakumar Thiagarajan <vasanth@atheros.com>
Signed-off-by: Vivek Natarajan <Vivek.Natarajan@atheros.com>
Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 21 insertions, 0 deletions

diff --git a/drivers/net/wireless/ath/ath9k/xmit.c b/drivers/net/wireless/ath/ath9k/xmit.c
index 2bb8c91bf4f9..6f91a8ae616f 100644
--- a/drivers/net/wireless/ath/ath9k/xmit.c
+++ b/drivers/net/wireless/ath/ath9k/xmit.c
@@ -1644,6 +1644,14 @@ static int ath_tx_setup_buffer(struct ieee80211_hw *hw, struct ath_buf *bf,
         }
 
         bf->bf_buf_addr = bf->bf_dmacontext;
+
+        /* tag if this is a nullfunc frame to enable PS when AP acks it */
+        if (ieee80211_is_nullfunc(fc) && ieee80211_has_pm(fc)) {
+                bf->bf_isnullfunc = true;
+                sc->sc_flags &= ~SC_OP_NULLFUNC_COMPLETED;
+        } else
+                bf->bf_isnullfunc = false;
+
         return 0;
 }
 
@@ -2039,6 +2047,19 @@ static void ath_tx_processq(struct ath_softc *sc, struct ath_txq *txq)
                 }
 
                 /*
+                 * We now know the nullfunc frame has been ACKed so we
+                 * can disable RX.
+                 */
+                if (bf->bf_isnullfunc &&
+                    (ds->ds_txstat.ts_status & ATH9K_TX_ACKED)) {
+                        if ((sc->sc_flags & SC_OP_PS_ENABLED)) {
+                                sc->ps_enabled = true;
+                                ath9k_hw_setrxabort(sc->sc_ah, 1);
+                        } else
+                                sc->sc_flags |= SC_OP_NULLFUNC_COMPLETED;
+                }
+
+                /*
                  * Remove ath_buf's of the same transmit unit from txq,
                  * however leave the last descriptor back as the holding
                  * descriptor for hw.