iwlwifi: mvm: rs: fallback to legacy Tx columns

Allow switching back to legacy Tx columns so we'll stop doing
HT/VHT in case we're far from the AP. Stop active aggregation when
making a deciding to stay in a legacy column.
Despite having low legacy rates in the LQ table lower entries
it doesn't help much in case we're doing aggregations as the
aggregation was being transmitted in the initial rate of the table.

This should help traffic stalls when far from the AP.

Cc: <stable@vger.kernel.org> [3.14]
Signed-off-by: Eyal Shapira <eyalx.shapira@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>

drivers/net/wireless/iwlwifi/mvm/rs.c

@@ -142,7 +142,7 @@ enum rs_column_mode {
 	RS_MIMO2,
 };
 
-#define MAX_NEXT_COLUMNS 5
+#define MAX_NEXT_COLUMNS 7
 #define MAX_COLUMN_CHECKS 3
 
 typedef bool (*allow_column_func_t) (struct iwl_mvm *mvm,
@@ -214,6 +214,8 @@ static const struct rs_tx_column rs_tx_columns[] = {
 			RS_COLUMN_SISO_ANT_B,
 			RS_COLUMN_MIMO2,
 			RS_COLUMN_MIMO2_SGI,
+			RS_COLUMN_INVALID,
+			RS_COLUMN_INVALID,
 		},
 	},
 	[RS_COLUMN_LEGACY_ANT_B] = {
@@ -225,6 +227,8 @@ static const struct rs_tx_column rs_tx_columns[] = {
 			RS_COLUMN_SISO_ANT_B,
 			RS_COLUMN_MIMO2,
 			RS_COLUMN_MIMO2_SGI,
+			RS_COLUMN_INVALID,
+			RS_COLUMN_INVALID,
 		},
 	},
 	[RS_COLUMN_SISO_ANT_A] = {
@@ -236,6 +240,8 @@ static const struct rs_tx_column rs_tx_columns[] = {
 			RS_COLUMN_SISO_ANT_A_SGI,
 			RS_COLUMN_SISO_ANT_B_SGI,
 			RS_COLUMN_MIMO2_SGI,
+			RS_COLUMN_LEGACY_ANT_A,
+			RS_COLUMN_LEGACY_ANT_B,
 		},
 		.checks = {
 			rs_siso_allow,
@@ -250,6 +256,8 @@ static const struct rs_tx_column rs_tx_columns[] = {
 			RS_COLUMN_SISO_ANT_B_SGI,
 			RS_COLUMN_SISO_ANT_A_SGI,
 			RS_COLUMN_MIMO2_SGI,
+			RS_COLUMN_LEGACY_ANT_A,
+			RS_COLUMN_LEGACY_ANT_B,
 		},
 		.checks = {
 			rs_siso_allow,
@@ -265,6 +273,8 @@ static const struct rs_tx_column rs_tx_columns[] = {
 			RS_COLUMN_SISO_ANT_A,
 			RS_COLUMN_SISO_ANT_B,
 			RS_COLUMN_MIMO2,
+			RS_COLUMN_LEGACY_ANT_A,
+			RS_COLUMN_LEGACY_ANT_B,
 		},
 		.checks = {
 			rs_siso_allow,
@@ -281,6 +291,8 @@ static const struct rs_tx_column rs_tx_columns[] = {
 			RS_COLUMN_SISO_ANT_B,
 			RS_COLUMN_SISO_ANT_A,
 			RS_COLUMN_MIMO2,
+			RS_COLUMN_LEGACY_ANT_A,
+			RS_COLUMN_LEGACY_ANT_B,
 		},
 		.checks = {
 			rs_siso_allow,
@@ -296,6 +308,8 @@ static const struct rs_tx_column rs_tx_columns[] = {
 			RS_COLUMN_SISO_ANT_A_SGI,
 			RS_COLUMN_SISO_ANT_B_SGI,
 			RS_COLUMN_MIMO2_SGI,
+			RS_COLUMN_LEGACY_ANT_A,
+			RS_COLUMN_LEGACY_ANT_B,
 		},
 		.checks = {
 			rs_mimo_allow,
@@ -311,6 +325,8 @@ static const struct rs_tx_column rs_tx_columns[] = {
 			RS_COLUMN_SISO_ANT_A,
 			RS_COLUMN_SISO_ANT_B,
 			RS_COLUMN_MIMO2,
+			RS_COLUMN_LEGACY_ANT_A,
+			RS_COLUMN_LEGACY_ANT_B,
 		},
 		.checks = {
 			rs_mimo_allow,
@@ -2070,8 +2086,18 @@ static void rs_rate_scale_perform(struct iwl_mvm *mvm,
 		 * stay with best antenna legacy modulation for a while
 		 * before next round of mode comparisons. */
 		tbl1 = &(lq_sta->lq_info[lq_sta->active_tbl]);
-		if (is_legacy(&tbl1->rate) && !sta->ht_cap.ht_supported) {
+		if (is_legacy(&tbl1->rate)) {
 			IWL_DEBUG_RATE(mvm, "LQ: STAY in legacy table\n");
+
+			if (tid != IWL_MAX_TID_COUNT) {
+				tid_data = &sta_priv->tid_data[tid];
+				if (tid_data->state != IWL_AGG_OFF) {
+					IWL_DEBUG_RATE(mvm,
+						       "Stop aggregation on tid %d\n",
+						       tid);
+					ieee80211_stop_tx_ba_session(sta, tid);
+				}
+			}
 			rs_set_stay_in_table(mvm, 1, lq_sta);
 		} else {
 		/* If we're in an HT mode, and all 3 mode switch actions