From b5655b7247a657bd4b590218a68ed99bbab318f6 Mon Sep 17 00:00:00 2001
From: cinap_lenrek <cinap_lenrek@felloff.net>
Date: Fri, 10 Jul 2015 09:04:05 +0200
Subject: wifi: adjust transmit rate on error (for etheriwl), small mkfile
 changes

Wnode gets two new counters: txcount and txerror
and actrate pointer that will be between minrate
and maxrate.

driver should use actrate instead of maxrate for
transmission when it can provide error feedback.

when a driver detects a transmission failed, it calls
wifitxfail() with the original packet. wifitxfail() then
reduces wn->actrate.

every 256th packet, we optimistically increase wn->actrate
before transmitting.
---
 sys/src/9/pc/wifi.c | 31 ++++++++++++++++++++++++++++---
 1 file changed, 28 insertions(+), 3 deletions(-)

(limited to 'sys/src/9/pc/wifi.c')

diff --git a/sys/src/9/pc/wifi.c b/sys/src/9/pc/wifi.c
index 4b9b3639d..77d2deb96 100644
--- a/sys/src/9/pc/wifi.c
+++ b/sys/src/9/pc/wifi.c
@@ -156,11 +156,18 @@ wifitx(Wifi *wifi, Wnode *wn, Block *b)
 	w->seq[0] = seq;
 	w->seq[1] = seq>>8;
 
-	if((w->fc[0] & 0x0c) != 0x00)
+	if((w->fc[0] & 0x0c) != 0x00){
 		b = wifiencrypt(wifi, wn, b);
+		if(b == nil)
+			return;
+	}
+
+	if((wn->txcount++ & 255) == 255){
+		if(wn->actrate != nil && wn->actrate < wn->maxrate)
+			wn->actrate++;
+	}
 
-	if(b != nil)
-		(*wifi->transmit)(wifi, wn, b);
+	(*wifi->transmit)(wifi, wn, b);
 }
 
 static Wnode*
@@ -196,6 +203,23 @@ nodelookup(Wifi *wifi, uchar *bssid, int new)
 	return nn;
 }
 
+void
+wifitxfail(Wifi *wifi, Block *b)
+{
+	Wifipkt *w;
+	Wnode *wn;
+
+	if(b == nil)
+		return;
+	w = (Wifipkt*)b->rp;
+	wn = nodelookup(wifi, w->a1, 0);
+	if(wn == nil)
+		return;
+	wn->txerror++;
+	if(wn->actrate != nil && wn->actrate > wn->minrate)
+		wn->actrate--;
+}
+
 static uchar*
 putrates(uchar *p, uchar *rates)
 {
@@ -417,6 +441,7 @@ recvbeacon(Wifi *wifi, Wnode *wn, uchar *d, int len)
 						break;
 					}
 				}
+				wn->actrate = wn->maxrate;
 			}
 			break;
 		case 3:		/* DSPARAMS */
-- 
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