iwlwifi: fix in-column rate scaling
This patch fixes cases that the code raised or didn't decrease
the rate although the success ratio was not good.
Signed-off-by: Guy Cohen <guy.cohen@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/iwlwifi/iwl-4965-rs.c b/drivers/net/wireless/iwlwifi/iwl-4965-rs.c
index f28b3cc..a89639f 100644
--- a/drivers/net/wireless/iwlwifi/iwl-4965-rs.c
+++ b/drivers/net/wireless/iwlwifi/iwl-4965-rs.c
@@ -1336,7 +1336,7 @@
lq_sta->search_better_tbl = 1;
goto out;
}
-
+ break;
case IWL_LEGACY_SWITCH_SISO:
IWL_DEBUG_RATE("LQ: Legacy switch to SISO\n");
@@ -1422,9 +1422,9 @@
lq_sta->search_better_tbl = 1;
goto out;
}
-
+ break;
case IWL_SISO_SWITCH_MIMO2:
- IWL_DEBUG_RATE("LQ: SISO switch to MIMO\n");
+ IWL_DEBUG_RATE("LQ: SISO switch to MIMO2\n");
memcpy(search_tbl, tbl, sz);
search_tbl->is_SGI = 0;
search_tbl->ant_type = ANT_AB; /*FIXME:RS*/
@@ -1689,6 +1689,7 @@
u8 active_tbl = 0;
u8 done_search = 0;
u16 high_low;
+ s32 sr;
#ifdef CONFIG_IWL4965_HT
u8 tid = MAX_TID_COUNT;
#endif
@@ -1864,6 +1865,8 @@
low = high_low & 0xff;
high = (high_low >> 8) & 0xff;
+ sr = window->success_ratio;
+
/* Collect measured throughputs for current and adjacent rates */
current_tpt = window->average_tpt;
if (low != IWL_RATE_INVALID)
@@ -1871,19 +1874,22 @@
if (high != IWL_RATE_INVALID)
high_tpt = tbl->win[high].average_tpt;
- /* Assume rate increase */
- scale_action = 1;
+ scale_action = 0;
/* Too many failures, decrease rate */
- if ((window->success_ratio <= IWL_RATE_DECREASE_TH) ||
- (current_tpt == 0)) {
+ if ((sr <= IWL_RATE_DECREASE_TH) || (current_tpt == 0)) {
IWL_DEBUG_RATE("decrease rate because of low success_ratio\n");
scale_action = -1;
/* No throughput measured yet for adjacent rates; try increase. */
} else if ((low_tpt == IWL_INVALID_VALUE) &&
- (high_tpt == IWL_INVALID_VALUE))
- scale_action = 1;
+ (high_tpt == IWL_INVALID_VALUE)) {
+
+ if (high != IWL_RATE_INVALID && sr >= IWL_RATE_INCREASE_TH)
+ scale_action = 1;
+ else if (low != IWL_RATE_INVALID)
+ scale_action = -1;
+ }
/* Both adjacent throughputs are measured, but neither one has better
* throughput; we're using the best rate, don't change it! */
@@ -1899,9 +1905,10 @@
/* Higher adjacent rate's throughput is measured */
if (high_tpt != IWL_INVALID_VALUE) {
/* Higher rate has better throughput */
- if (high_tpt > current_tpt)
+ if (high_tpt > current_tpt &&
+ sr >= IWL_RATE_INCREASE_TH) {
scale_action = 1;
- else {
+ } else {
IWL_DEBUG_RATE
("decrease rate because of high tpt\n");
scale_action = -1;
@@ -1914,23 +1921,17 @@
IWL_DEBUG_RATE
("decrease rate because of low tpt\n");
scale_action = -1;
- } else
+ } else if (sr >= IWL_RATE_INCREASE_TH) {
scale_action = 1;
+ }
}
}
/* Sanity check; asked for decrease, but success rate or throughput
* has been good at old rate. Don't change it. */
- if (scale_action == -1) {
- if ((low != IWL_RATE_INVALID) &&
- ((window->success_ratio > IWL_RATE_HIGH_TH) ||
+ if ((scale_action == -1) && (low != IWL_RATE_INVALID) &&
+ ((sr > IWL_RATE_HIGH_TH) ||
(current_tpt > (100 * tbl->expected_tpt[low]))))
- scale_action = 0;
-
- /* Sanity check; asked for increase, but success rate has not been great
- * even at old rate, higher rate will be worse. Don't change it. */
- } else if ((scale_action == 1) &&
- (window->success_ratio < IWL_RATE_INCREASE_TH))
scale_action = 0;
switch (scale_action) {
@@ -1959,7 +1960,7 @@
"high %d type %d\n",
index, scale_action, low, high, tbl->lq_type);
- lq_update:
+lq_update:
/* Replace uCode's rate table for the destination station. */
if (update_lq) {
rate = rate_n_flags_from_tbl(tbl, index, is_green);