This adapts the use of the firmware multi-rate retry table to always
make use of all available slots.
The table specifies 16 Tx rates the firmware can use, one per Tx attempt.
For example, on a 5 GHz channel the current code fills this table with
static values like this:
MCS-7 MCS-6 MCS-5 MCS-4 MCS-3 MCS-2 MCS-1 MCS-0 OFDM6 OFDM6 OFDM6 ...
We then point the firmware at the entry in this table where Tx attempts
should begin. If we're currently sending at, say, MCS-5, then the rate
at the 3rd entry will be used first, then the 4th, and so on.
This is in fact what a comment in the Linux driver suggests doing for
non-11n operation, and I guess that's why Damien implemented it this way.
When I added 11n mode to the driver, with MCS 0 to 7, I kept this design.
With MIMO this approach won't work because then we'll have two ranges of
continous rates: MCS 0 to 7 (single antenna) and MCS 8 to 15 (dual antenna).
MiRA never mixes Tx rates using different amounts of antennas.
So we will need an approach that looks more like iwm(4) does it, where the
table is continuously updated and our the Tx current rate is at the front.
While we're transmitting at MCS 5, the table now looks like this:
MCS-5 MCS-4 MCS-3 MCS-2 MCS-1 MCS-0 OFDM6 OFDM6 OFDM6 OFDM6 OFDM6 OFDM6 ...
Once we support MIMO, the table would look like this while we're using MCS-9:
MCS-9 MCS-8 OFDM6 OFDM6 OFDM6 OFDM6 OFDM6 OFDM6 ...
So this change prepares for MIMO and makes sure that the firmware can
always make use of the full amount of Tx attempts.
diff 6f793971788fd7061f66330336cbeb5103b717c3
24c5886569df7f9428f24e6e74c71e02cba8c34c
blob - 110bbe97b980b338acd8aa61fbabd33926c207be
blob + 8476916e4337cb6e681c11f26fc1fca5f4a48334
--- sys/dev/pci/if_iwn.c
+++ sys/dev/pci/if_iwn.c
@@ -157,6 +157,7 @@ void iwn_rx_phy(struct iwn_softc *, struct
iwn_rx_des
struct iwn_rx_data *);
void iwn_rx_done(struct iwn_softc *, struct iwn_rx_desc *,
struct iwn_rx_data *, struct mbuf_list *);
+void iwn_mira_choose(struct iwn_softc *, struct ieee80211_node *);
void iwn_rx_compressed_ba(struct iwn_softc *, struct iwn_rx_desc *,
struct iwn_rx_data *);
void iwn5000_rx_calib_results(struct iwn_softc *,
@@ -1864,8 +1865,12 @@ iwn_iter_func(void *arg, struct ieee80211_node *ni)
struct iwn_softc *sc = arg;
struct iwn_node *wn = (void *)ni;
- if ((ni->ni_flags & IEEE80211_NODE_HT) == 0)
+ if ((ni->ni_flags & IEEE80211_NODE_HT) == 0) {
+ int old_txrate = ni->ni_txrate;
ieee80211_amrr_choose(&sc->amrr, ni, &wn->amn);
+ if (old_txrate != ni->ni_txrate)
+ iwn_set_link_quality(sc, ni);
+ }
}
void
@@ -2254,6 +2259,29 @@ iwn_rx_done(struct iwn_softc *sc, struct iwn_rx_desc *
ieee80211_release_node(ic, ni);
}
+void
+iwn_mira_choose(struct iwn_softc *sc, struct ieee80211_node *ni)
+{
+ struct ieee80211com *ic = &sc->sc_ic;
+ struct iwn_node *wn = (void *)ni;
+ int best_mcs = ieee80211_mira_get_best_mcs(&wn->mn);
+
+ ieee80211_mira_choose(&wn->mn, ic, ni);
+
+ /*
+ * Update firmware's LQ retry table if MiRA has chosen a new MCS.
+ *
+ * We only need to do this if the best MCS has changed because
+ * we ask firmware to use a fixed MCS while MiRA is probing a
+ * candidate MCS.
+ * While not probing we ask firmware to retry at lower rates in case
+ * Tx at the newly chosen best MCS ends up failing, and then report
+ * any resulting Tx retries to MiRA in order to trigger probing.
+ */
+ if (best_mcs != ieee80211_mira_get_best_mcs(&wn->mn))
+ iwn_set_link_quality(sc, ni);
+}
+
/* Process an incoming Compressed BlockAck. */
void
iwn_rx_compressed_ba(struct iwn_softc *sc, struct iwn_rx_desc *desc,
@@ -2352,6 +2380,8 @@ iwn_rx_compressed_ba(struct iwn_softc *sc, struct iwn_
if (wn->mn.ampdu_size > 0)
ieee80211_mira_choose(&wn->mn, ic, ni);
}
+ if (wn->mn.ampdu_size > 0)
+ iwn_mira_choose(sc, ni);
}
/*
@@ -2584,7 +2614,7 @@ iwn_ampdu_tx_done(struct iwn_softc *sc, struct iwn_tx_
wn->mn.retries++;
if (txfail)
wn->mn.txfail++;
- ieee80211_mira_choose(&wn->mn, ic, ni);
+ iwn_mira_choose(sc, ni);
}
if (txfail)
@@ -2778,7 +2808,7 @@ iwn_tx_done(struct iwn_softc *sc, struct iwn_rx_desc *
wn->mn.retries++;
if (txfail)
wn->mn.txfail++;
- ieee80211_mira_choose(&wn->mn, ic, data->ni);
+ iwn_mira_choose(sc, data->ni);
}
} else if (data->txrate == data->ni->ni_txrate) {
wn->amn.amn_txcnt++;
@@ -3526,11 +3556,8 @@ iwn_tx(struct iwn_softc *sc, struct mbuf *m, struct ie
txant = IWN_LSB(sc->txchainmask);
tx->rflags |= IWN_RFLAG_ANT(txant);
} else {
- if (ni->ni_flags & IEEE80211_NODE_HT)
- tx->linkq = 7 - ni->ni_txmcs; /* XXX revisit for MIMO */
- else
- tx->linkq = ni->ni_rates.rs_nrates - ni->ni_txrate - 1;
- flags |= IWN_TX_LINKQ; /* enable MRR */
+ tx->linkq = 0; /* initial index into firmware LQ retry table */
+ flags |= IWN_TX_LINKQ; /* enable multi-rate retry */
}
/* Set physical address of "scratch area". */
tx->loaddr = htole32(IWN_LOADDR(data->scratch_paddr));
@@ -3882,11 +3909,10 @@ iwn_set_link_quality(struct iwn_softc *sc, struct ieee
{
struct ieee80211com *ic = &sc->sc_ic;
struct iwn_node *wn = (void *)ni;
- struct ieee80211_rateset *rs = &ni->ni_rates;
struct iwn_cmd_link_quality linkq;
const struct iwn_rate *rinfo;
uint8_t txant;
- int i, txrate;
+ int i;
/* Use the first valid TX antenna. */
txant = IWN_LSB(sc->txchainmask);
@@ -3899,11 +3925,11 @@ iwn_set_link_quality(struct iwn_softc *sc, struct ieee
linkq.ampdu_threshold = 3;
linkq.ampdu_limit = htole16(4000); /* 4ms */
+ i = 0;
if (ni->ni_flags & IEEE80211_NODE_HT) {
- /* Fill LQ table with MCS 7 - 0 (XXX revisit for MIMO) */
- i = 0;
- for (txrate = 7; txrate >= 0; txrate--) {
- rinfo = &iwn_rates[iwn_mcs2ridx[txrate]];
+ int txmcs;
+ for (txmcs = ni->ni_txmcs; txmcs >= 0; txmcs--) {
+ rinfo = &iwn_rates[iwn_mcs2ridx[txmcs]];
linkq.retry[i].plcp = rinfo->ht_plcp;
linkq.retry[i].rflags = rinfo->ht_flags;
@@ -3916,27 +3942,25 @@ iwn_set_link_quality(struct iwn_softc *sc, struct ieee
if (++i >= IWN_MAX_TX_RETRIES)
break;
}
-
- /* Fill the rest with the lowest basic rate. */
- rinfo = &iwn_rates[iwn_rval2ridx(ieee80211_min_basic_rate(ic))];
- while (i < IWN_MAX_TX_RETRIES) {
- linkq.retry[i].plcp = rinfo->plcp;
- linkq.retry[i].rflags = rinfo->flags;
- linkq.retry[i].rflags |= IWN_RFLAG_ANT(txant);
- i++;
- }
} else {
- /* Start at highest available bit-rate. */
- txrate = rs->rs_nrates - 1;
- for (i = 0; i < IWN_MAX_TX_RETRIES; i++) {
+ int txrate;
+ for (txrate = ni->ni_txrate; txrate >= 0; txrate--) {
rinfo = &iwn_rates[wn->ridx[txrate]];
linkq.retry[i].plcp = rinfo->plcp;
linkq.retry[i].rflags = rinfo->flags;
linkq.retry[i].rflags |= IWN_RFLAG_ANT(txant);
- /* Next retry at immediate lower bit-rate. */
- if (txrate > 0)
- txrate--;
+ if (++i >= IWN_MAX_TX_RETRIES)
+ break;
}
+ }
+
+ /* Fill the rest with the lowest basic rate. */
+ rinfo = &iwn_rates[iwn_rval2ridx(ieee80211_min_basic_rate(ic))];
+ while (i < IWN_MAX_TX_RETRIES) {
+ linkq.retry[i].plcp = rinfo->plcp;
+ linkq.retry[i].rflags = rinfo->flags;
+ linkq.retry[i].rflags |= IWN_RFLAG_ANT(txant);
+ i++;
}
return iwn_cmd(sc, IWN_CMD_LINK_QUALITY, &linkq, sizeof linkq, 1);
