Make iwm(4) use only antenna B for single-antenna Tx on 9k devices.

This matches what Linux and FreeBSD do.
According to Linux commit logs using antenna A for single-antenna Tx
on 9k devices is "wrong" (with no further explanation given).
I suspect it only matters if Bluetooth is active, since antenna A has
obviously been working for us. But who knows...

diff --git a/sys/dev/pci/if_iwm.c b/sys/dev/pci/if_iwm.c
index 412e6ef..a04c767 100644 (file)
--- a/sys/dev/pci/if_iwm.c
+++ b/sys/dev/pci/if_iwm.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: if_iwm.c,v 1.347 2021/07/09 11:04:05 stsp Exp $       */
+/*     $OpenBSD: if_iwm.c,v 1.348 2021/07/09 11:11:36 stsp Exp $       */
 
 /*
  * Copyright (c) 2014, 2016 genua gmbh <info@genua.de>
@@ -6272,6 +6272,8 @@ iwm_tx_fill_cmd(struct iwm_softc *sc, struct iwm_node *in,
        rinfo = &iwm_rates[ridx];
        if (iwm_is_mimo_ht_plcp(rinfo->ht_plcp))
                rate_flags = IWM_RATE_MCS_ANT_AB_MSK;
+       else if (sc->sc_device_family == IWM_DEVICE_FAMILY_9000)
+               rate_flags = IWM_RATE_MCS_ANT_B_MSK;
        else
                rate_flags = IWM_RATE_MCS_ANT_A_MSK;
        if (IWM_RIDX_IS_CCK(ridx))
@@ -8717,6 +8719,8 @@ iwm_setrates(struct iwm_node *in, int async)
 
                if (iwm_is_mimo_ht_plcp(ht_plcp))
                        tab |= IWM_RATE_MCS_ANT_AB_MSK;
+               else if (sc->sc_device_family == IWM_DEVICE_FAMILY_9000)
+                       tab |= IWM_RATE_MCS_ANT_B_MSK;
                else
                        tab |= IWM_RATE_MCS_ANT_A_MSK;
 
@@ -8732,11 +8736,17 @@ iwm_setrates(struct iwm_node *in, int async)
                tab = iwm_rates[ridx_min].plcp;
                if (IWM_RIDX_IS_CCK(ridx_min))
                        tab |= IWM_RATE_MCS_CCK_MSK;
-               tab |= IWM_RATE_MCS_ANT_A_MSK;
+               if (sc->sc_device_family == IWM_DEVICE_FAMILY_9000)
+                       tab |= IWM_RATE_MCS_ANT_B_MSK;
+               else
+                       tab |= IWM_RATE_MCS_ANT_A_MSK;
                lqcmd.rs_table[j++] = htole32(tab);
        }
 
-       lqcmd.single_stream_ant_msk = IWM_ANT_A;
+       if (sc->sc_device_family == IWM_DEVICE_FAMILY_9000)
+               lqcmd.single_stream_ant_msk = IWM_ANT_B;
+       else
+               lqcmd.single_stream_ant_msk = IWM_ANT_A;
        lqcmd.dual_stream_ant_msk = IWM_ANT_AB;
 
        lqcmd.agg_time_limit = htole16(4000);   /* 4ms */