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ath9k: Remove dead code in rate control
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ath9k rate control is based on only PER (packet error rate),
remove unused code which was intented to do rssi based rate
selection.

Signed-off-by: Vasanthakumar Thiagarajan <vasanth@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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Vasanthakumar Thiagarajan authored and John W. Linville committed Jul 24, 2009
1 parent e25739a commit 39a4caf
Showing 1 changed file with 4 additions and 159 deletions.
163 changes: 4 additions & 159 deletions drivers/net/wireless/ath/ath9k/rc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -607,47 +607,14 @@ static u8 ath_rc_get_highest_rix(struct ath_softc *sc,
const struct ath_rate_table *rate_table,
int *is_probing)
{
u32 dt, best_thruput, this_thruput, now_msec;
u32 best_thruput, this_thruput, now_msec;
u8 rate, next_rate, best_rate, maxindex, minindex;
int8_t rssi_last, rssi_reduce = 0, index = 0;

*is_probing = 0;

rssi_last = median(ath_rc_priv->rssi_last,
ath_rc_priv->rssi_last_prev,
ath_rc_priv->rssi_last_prev2);

/*
* Age (reduce) last ack rssi based on how old it is.
* The bizarre numbers are so the delta is 160msec,
* meaning we divide by 16.
* 0msec <= dt <= 25msec: don't derate
* 25msec <= dt <= 185msec: derate linearly from 0 to 10dB
* 185msec <= dt: derate by 10dB
*/
int8_t index = 0;

now_msec = jiffies_to_msecs(jiffies);
dt = now_msec - ath_rc_priv->rssi_time;

if (dt >= 185)
rssi_reduce = 10;
else if (dt >= 25)
rssi_reduce = (u8)((dt - 25) >> 4);

/* Now reduce rssi_last by rssi_reduce */
if (rssi_last < rssi_reduce)
rssi_last = 0;
else
rssi_last -= rssi_reduce;

/*
* Now look up the rate in the rssi table and return it.
* If no rates match then we return 0 (lowest rate)
*/

*is_probing = 0;
best_thruput = 0;
maxindex = ath_rc_priv->max_valid_rate-1;

minindex = 0;
best_rate = minindex;

Expand Down Expand Up @@ -687,7 +654,6 @@ static u8 ath_rc_get_highest_rix(struct ath_softc *sc,
}

rate = best_rate;
ath_rc_priv->rssi_last_lookup = rssi_last;

/*
* Must check the actual rate (ratekbps) to account for
Expand Down Expand Up @@ -977,10 +943,6 @@ static bool ath_rc_update_per(struct ath_softc *sc,
(nretry_to_per_lookup[retries] >> 3));
}

ath_rc_priv->rssi_last_prev2 = ath_rc_priv->rssi_last_prev;
ath_rc_priv->rssi_last_prev = ath_rc_priv->rssi_last;
ath_rc_priv->rssi_last = tx_info_priv->tx.ts_rssi;
ath_rc_priv->rssi_time = now_msec;

/*
* If we got at most one retry then increase the max rate if
Expand Down Expand Up @@ -1024,18 +986,9 @@ static bool ath_rc_update_per(struct ath_softc *sc,
/*
* Don't update anything. We don't know if
* this was because of collisions or poor signal.
*
* Later: if rssi_ack is close to
* ath_rc_priv->state[txRate].rssi_thres and we see lots
* of retries, then we could increase
* ath_rc_priv->state[txRate].rssi_thres.
*/
ath_rc_priv->hw_maxretry_pktcnt = 0;
} else {
int32_t rssi_ackAvg;
int8_t rssi_thres;
int8_t rssi_ack_vmin;

/*
* It worked with no retries. First ignore bogus (small)
* rssi_ack values.
Expand All @@ -1045,43 +998,9 @@ static bool ath_rc_update_per(struct ath_softc *sc,
ath_rc_priv->hw_maxretry_pktcnt++;
}

if (tx_info_priv->tx.ts_rssi <
rate_table->info[tx_rate].rssi_ack_validmin)
goto exit;

/* Average the rssi */
if (tx_rate != ath_rc_priv->rssi_sum_rate) {
ath_rc_priv->rssi_sum_rate = tx_rate;
ath_rc_priv->rssi_sum =
ath_rc_priv->rssi_sum_cnt = 0;
}

ath_rc_priv->rssi_sum += tx_info_priv->tx.ts_rssi;
ath_rc_priv->rssi_sum_cnt++;

if (ath_rc_priv->rssi_sum_cnt < 4)
goto exit;

rssi_ackAvg =
(ath_rc_priv->rssi_sum + 2) / 4;
rssi_thres =
ath_rc_priv->state[tx_rate].rssi_thres;
rssi_ack_vmin =
rate_table->info[tx_rate].rssi_ack_validmin;

ath_rc_priv->rssi_sum =
ath_rc_priv->rssi_sum_cnt = 0;

/* Now reduce the current rssi threshold */
if ((rssi_ackAvg < rssi_thres + 2) &&
(rssi_thres > rssi_ack_vmin)) {
ath_rc_priv->state[tx_rate].rssi_thres--;
}

state_change = true;
}
}
exit:

return state_change;
}

Expand All @@ -1093,11 +1012,6 @@ static void ath_rc_update_ht(struct ath_softc *sc,
struct ath_tx_info_priv *tx_info_priv,
int tx_rate, int xretries, int retries)
{
#define CHK_RSSI(rate) \
((ath_rc_priv->state[(rate)].rssi_thres + \
rate_table->info[(rate)].rssi_ack_deltamin) > \
ath_rc_priv->state[(rate)+1].rssi_thres)

u32 now_msec = jiffies_to_msecs(jiffies);
int rate;
u8 last_per;
Expand All @@ -1108,13 +1022,6 @@ static void ath_rc_update_ht(struct ath_softc *sc,
if ((tx_rate < 0) || (tx_rate > rate_table->rate_cnt))
return;

/* To compensate for some imbalance between ctrl and ext. channel */

if (WLAN_RC_PHY_40(rate_table->info[tx_rate].phy))
tx_info_priv->tx.ts_rssi =
tx_info_priv->tx.ts_rssi < 3 ? 0 :
tx_info_priv->tx.ts_rssi - 3;

last_per = ath_rc_priv->state[tx_rate].per;

/* Update PER first */
Expand All @@ -1136,51 +1043,6 @@ static void ath_rc_update_ht(struct ath_softc *sc,
ath_rc_priv->probe_time = now_msec;
}

if (state_change) {
/*
* Make sure the rates above this have higher rssi thresholds.
* (Note: Monotonicity is kept within the OFDM rates and
* within the CCK rates. However, no adjustment is
* made to keep the rssi thresholds monotonically
* increasing between the CCK and OFDM rates.)
*/
for (rate = tx_rate; rate < size - 1; rate++) {
if (rate_table->info[rate+1].phy !=
rate_table->info[tx_rate].phy)
break;

if (CHK_RSSI(rate)) {
ath_rc_priv->state[rate+1].rssi_thres =
ath_rc_priv->state[rate].rssi_thres +
rate_table->info[rate].rssi_ack_deltamin;
}
}

/* Make sure the rates below this have lower rssi thresholds. */
for (rate = tx_rate - 1; rate >= 0; rate--) {
if (rate_table->info[rate].phy !=
rate_table->info[tx_rate].phy)
break;

if (CHK_RSSI(rate)) {
if (ath_rc_priv->state[rate+1].rssi_thres <
rate_table->info[rate].rssi_ack_deltamin)
ath_rc_priv->state[rate].rssi_thres = 0;
else {
ath_rc_priv->state[rate].rssi_thres =
ath_rc_priv->state[rate+1].rssi_thres -
rate_table->info[rate].rssi_ack_deltamin;
}

if (ath_rc_priv->state[rate].rssi_thres <
rate_table->info[rate].rssi_ack_validmin) {
ath_rc_priv->state[rate].rssi_thres =
rate_table->info[rate].rssi_ack_validmin;
}
}
}
}

/* Make sure the rates below this have lower PER */
/* Monotonicity is kept only for rates below the current rate. */
if (ath_rc_priv->state[tx_rate].per < last_per) {
Expand All @@ -1205,19 +1067,6 @@ static void ath_rc_update_ht(struct ath_softc *sc,
ath_rc_priv->state[rate].per;
}

/* Every so often, we reduce the thresholds and
* PER (different for CCK and OFDM). */
if (now_msec - ath_rc_priv->rssi_down_time >=
rate_table->rssi_reduce_interval) {

for (rate = 0; rate < size; rate++) {
if (ath_rc_priv->state[rate].rssi_thres >
rate_table->info[rate].rssi_ack_validmin)
ath_rc_priv->state[rate].rssi_thres -= 1;
}
ath_rc_priv->rssi_down_time = now_msec;
}

/* Every so often, we reduce the thresholds
* and PER (different for CCK and OFDM). */
if (now_msec - ath_rc_priv->per_down_time >=
Expand All @@ -1233,7 +1082,6 @@ static void ath_rc_update_ht(struct ath_softc *sc,
ath_debug_stat_retries(sc, tx_rate, xretries, retries,
ath_rc_priv->state[tx_rate].per);

#undef CHK_RSSI
}

static int ath_rc_get_rateindex(const struct ath_rate_table *rate_table,
Expand Down Expand Up @@ -1369,8 +1217,6 @@ static void ath_rc_init(struct ath_softc *sc,

/* Initialize thresholds according to the global rate table */
for (i = 0 ; i < ath_rc_priv->rate_table_size; i++) {
ath_rc_priv->state[i].rssi_thres =
rate_table->info[i].rssi_ack_validmin;
ath_rc_priv->state[i].per = 0;
}

Expand Down Expand Up @@ -1631,7 +1477,6 @@ static void *ath_rate_alloc_sta(void *priv, struct ieee80211_sta *sta, gfp_t gfp
return NULL;
}

rate_priv->rssi_down_time = jiffies_to_msecs(jiffies);
rate_priv->tx_triglevel_max = sc->sc_ah->caps.tx_triglevel_max;

return rate_priv;
Expand Down

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