Fix urtwn(4) 11b performance for RTL8188EU devices.

With 11b APs the firmware retries excessively unless we force it into
11b-only mode instead of mixed b/g. Perhaps a firmware bug, perhaps
a bug in our code elsewhere. For now, this makes it work.
ok kettenis

diff --git a/sys/dev/usb/if_urtwn.c b/sys/dev/usb/if_urtwn.c
index 65f9e4c..81f811c 100644 (file)
--- a/sys/dev/usb/if_urtwn.c
+++ b/sys/dev/usb/if_urtwn.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: if_urtwn.c,v 1.45 2015/05/10 15:10:46 stsp Exp $      */
+/*     $OpenBSD: if_urtwn.c,v 1.46 2015/05/10 19:40:56 stsp Exp $      */
 
 /*-
  * Copyright (c) 2010 Damien Bergamini <damien.bergamini@free.fr>
@@ -184,6 +184,10 @@ void               urtwn_read_rom(struct urtwn_softc *);
 void           urtwn_r88e_read_rom(struct urtwn_softc *);
 int            urtwn_media_change(struct ifnet *);
 int            urtwn_ra_init(struct urtwn_softc *);
+int            urtwn_r92c_ra_init(struct urtwn_softc *, u_int8_t, u_int32_t,
+                   int, uint32_t, int);
+int            urtwn_r88e_ra_init(struct urtwn_softc *, u_int8_t, u_int32_t,
+                   int, uint32_t, int);
 void           urtwn_tsf_sync_enable(struct urtwn_softc *);
 void           urtwn_set_led(struct urtwn_softc *, int, int);
 void           urtwn_calib_to(void *);
@@ -1083,7 +1087,6 @@ urtwn_ra_init(struct urtwn_softc *sc)
        struct ieee80211com *ic = &sc->sc_ic;
        struct ieee80211_node *ni = ic->ic_bss;
        struct ieee80211_rateset *rs = &ni->ni_rates;
-       struct r92c_fw_cmd_macid_cfg cmd;
        uint32_t rates, basicrates;
        uint8_t mode;
        int maxrate, maxbasicrate, error, i, j;
@@ -1114,6 +1117,24 @@ urtwn_ra_init(struct urtwn_softc *sc)
        DPRINTF(("mode=0x%x rates=0x%08x, basicrates=0x%08x\n",
            mode, rates, basicrates));
 
+       if (sc->chip & URTWN_CHIP_88E)
+               error = urtwn_r88e_ra_init(sc, mode, rates, maxrate,
+                   basicrates, maxbasicrate);
+       else
+               error = urtwn_r92c_ra_init(sc, mode, rates, maxrate,
+                   basicrates, maxbasicrate);
+
+       /* Indicate highest supported rate. */
+       ni->ni_txrate = rs->rs_nrates - 1;
+       return (error);
+}
+
+int urtwn_r92c_ra_init(struct urtwn_softc *sc, u_int8_t mode, u_int32_t rates,
+    int maxrate, uint32_t basicrates, int maxbasicrate)
+{
+       struct r92c_fw_cmd_macid_cfg cmd;
+       int error;
+
        /* Set rates mask for group addressed frames. */
        cmd.macid = URTWN_MACID_BC | URTWN_MACID_VALID;
        cmd.mask = htole32(mode << 28 | basicrates);
@@ -1142,8 +1163,28 @@ urtwn_ra_init(struct urtwn_softc *sc)
        urtwn_write_1(sc, R92C_INIDATA_RATE_SEL(URTWN_MACID_BSS),
            maxrate);
 
-       /* Indicate highest supported rate. */
-       ni->ni_txrate = rs->rs_nrates - 1;
+       return (0);
+}
+
+int
+urtwn_r88e_ra_init(struct urtwn_softc *sc, u_int8_t mode, u_int32_t rates,
+    int maxrate, uint32_t basicrates, int maxbasicrate)
+{
+       u_int32_t reg;
+
+       urtwn_write_1(sc, R92C_INIRTS_RATE_SEL, maxbasicrate);
+
+       reg = urtwn_read_4(sc, R92C_RRSR);
+       reg = RW(reg, R92C_RRSR_RATE_BITMAP, rates);
+       urtwn_write_4(sc, R92C_RRSR, reg);
+
+       /* 
+        * Workaround for performance problems with firmware rate adaptation:
+        * If the AP only supports 11b rates, disable mixed B/G mode.
+        */
+       if (mode != R92C_RAID_11B && maxrate <= 3 /* 11M */)
+               sc->sc_flags |= URTWN_FLAG_FORCE_RAID_11B;
+
        return (0);
 }
 
@@ -1312,6 +1353,9 @@ urtwn_newstate_cb(struct urtwn_softc *sc, void *arg)
                urtwn_write_4(sc, R92C_EDCA_VI_PARAM, 0x005e4317);
                urtwn_write_4(sc, R92C_EDCA_BE_PARAM, 0x00105320);
                urtwn_write_4(sc, R92C_EDCA_BK_PARAM, 0x0000a444);
+
+               /* Disable 11b-only AP workaround (see urtwn_r88e_ra_init). */
+               sc->sc_flags &= ~URTWN_FLAG_FORCE_RAID_11B;
        }
        switch (cmd->state) {
        case IEEE80211_S_INIT:
@@ -1417,10 +1461,8 @@ urtwn_newstate_cb(struct urtwn_softc *sc, void *arg)
                urtwn_write_1(sc, R92C_T2T_SIFS + 1, 10);
 
                /* Intialize rate adaptation. */
-               if (sc->chip & URTWN_CHIP_88E)
-                       ni->ni_txrate = ni->ni_rates.rs_nrates-1;
-               else
-                       urtwn_ra_init(sc);
+               urtwn_ra_init(sc);
+
                /* Turn link LED on. */
                urtwn_set_led(sc, URTWN_LED_LINK, 1);
 
@@ -1981,7 +2023,8 @@ urtwn_tx(struct urtwn_softc *sc, struct mbuf *m, struct ieee80211_node *ni)
 #endif
        if (!IEEE80211_IS_MULTICAST(wh->i_addr1) &&
            type == IEEE80211_FC0_TYPE_DATA) {
-               if (ic->ic_curmode == IEEE80211_MODE_11B)
+               if (ic->ic_curmode == IEEE80211_MODE_11B ||
+                   (sc->sc_flags & URTWN_FLAG_FORCE_RAID_11B))
                        raid = R92C_RAID_11B;
                else
                        raid = R92C_RAID_11BG;

diff --git a/sys/dev/usb/if_urtwnreg.h b/sys/dev/usb/if_urtwnreg.h
index edbad3d..8d46a6e 100644 (file)
--- a/sys/dev/usb/if_urtwnreg.h
+++ b/sys/dev/usb/if_urtwnreg.h
@@ -1,4 +1,4 @@
-/*     $OpenBSD: if_urtwnreg.h,v 1.5 2015/05/04 11:46:29 stsp Exp $    */
+/*     $OpenBSD: if_urtwnreg.h,v 1.6 2015/05/10 19:40:56 stsp Exp $    */
 
 /*-
  * Copyright (c) 2010 Damien Bergamini <damien.bergamini@free.fr>
@@ -1153,7 +1153,8 @@ struct urtwn_softc {
        struct usbd_pipe                *tx_pipe[R92C_MAX_EPOUT];
        int                             ac2idx[EDCA_NUM_AC];
        u_int                           sc_flags;
-#define URTWN_FLAG_CCK_HIPWR   0x01
+#define URTWN_FLAG_CCK_HIPWR           0x01
+#define URTWN_FLAG_FORCE_RAID_11B      0x02
 
        u_int                           chip;
 #define        URTWN_CHIP_92C          0x01