mac80211: Shortcut minstrel_ht rate setup for non-MRR capable devices

Devices without multi rate retry support won't be able to use all rates
as specified by mintrel_ht. Hence, we can simply skip setting up further
rates as the devices will only use the first one.

Also add a special case for devices with only two possible tx rates. We
use sample_rate -> max_prob_rate for sampling and max_tp_rate ->
max_prob_rate by default.

Signed-off-by: Helmut Schaa <helmut.schaa@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/net/mac80211/rc80211_minstrel_ht.c b/net/mac80211/rc80211_minstrel_ht.c
index bce14fb..8212a8b 100644 (file)
--- a/net/mac80211/rc80211_minstrel_ht.c
+++ b/net/mac80211/rc80211_minstrel_ht.c
@@ -598,19 +598,46 @@ minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta,
                sample = true;
                minstrel_ht_set_rate(mp, mi, &ar[0], sample_idx,
                        txrc, true, false);
-               minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate,
-                       txrc, false, false);
                info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE;
        } else {
                minstrel_ht_set_rate(mp, mi, &ar[0], mi->max_tp_rate,
                        txrc, false, false);
-               minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate2,
-                       txrc, false, true);
        }
-       minstrel_ht_set_rate(mp, mi, &ar[2], mi->max_prob_rate, txrc, false, !sample);
 
-       ar[3].count = 0;
-       ar[3].idx = -1;
+       if (mp->hw->max_rates >= 3) {
+               /*
+                * At least 3 tx rates supported, use
+                * sample_rate -> max_tp_rate -> max_prob_rate for sampling and
+                * max_tp_rate -> max_tp_rate2 -> max_prob_rate by default.
+                */
+               if (sample_idx >= 0)
+                       minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate,
+                               txrc, false, false);
+               else
+                       minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate2,
+                               txrc, false, true);
+
+               minstrel_ht_set_rate(mp, mi, &ar[2], mi->max_prob_rate,
+                                    txrc, false, !sample);
+
+               ar[3].count = 0;
+               ar[3].idx = -1;
+       } else if (mp->hw->max_rates == 2) {
+               /*
+                * Only 2 tx rates supported, use
+                * sample_rate -> max_prob_rate for sampling and
+                * max_tp_rate -> max_prob_rate by default.
+                */
+               minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_prob_rate,
+                                    txrc, false, !sample);
+
+               ar[2].count = 0;
+               ar[2].idx = -1;
+       } else {
+               /* Not using MRR, only use the first rate */
+               ar[1].count = 0;
+               ar[1].idx = -1;
+       }
 
        mi->total_packets++;