diff --git a/sys/dev/rtwn/rtl8188e/pci/r88ee_attach.c b/sys/dev/rtwn/rtl8188e/pci/r88ee_attach.c
--- a/sys/dev/rtwn/rtl8188e/pci/r88ee_attach.c
+++ b/sys/dev/rtwn/rtl8188e/pci/r88ee_attach.c
@@ -191,7 +191,7 @@
 	sc->sc_init_antsel		= rtwn_nop_softc;
 	sc->sc_post_init		= r88ee_post_init;
 	sc->sc_init_bcnq1_boundary	= rtwn_nop_int_softc;
-	sc->sc_set_tx_power		= rtwn_nop_int_softc_vap;
+	sc->sc_set_tx_power		= r92c_set_tx_power;
 
 	sc->mac_prog			= &rtl8188e_mac[0];
 	sc->mac_size			= nitems(rtl8188e_mac);
diff --git a/sys/dev/rtwn/rtl8188e/r88e_chan.c b/sys/dev/rtwn/rtl8188e/r88e_chan.c
--- a/sys/dev/rtwn/rtl8188e/r88e_chan.c
+++ b/sys/dev/rtwn/rtl8188e/r88e_chan.c
@@ -84,6 +84,7 @@
 r88e_get_txpower(struct rtwn_softc *sc, int chain,
     struct ieee80211_channel *c, uint8_t power[RTWN_RIDX_COUNT])
 {
+	const struct ieee80211com *ic = &sc->sc_ic;
 	struct r92c_softc *rs = sc->sc_priv;
 	const struct rtwn_r88e_txpwr *rt = rs->rs_txpwr;
 	uint8_t cckpow, ofdmpow, bw20pow, htpow = 0;
@@ -96,15 +97,36 @@
 		return;
 	}
 
-	/* XXX net80211 regulatory */
+	/*
+	 * Treat the entries in 1/2 dBm resolution where 0 = 0dBm.
+	 * Apply the adjustments afterwards; assume that the vendor
+	 * driver is applying offsets to make up for the actual
+	 * target power in dBm.
+	 */
 
 	max_mcs = RTWN_RIDX_HT_MCS(sc->ntxchains * 8 - 1);
 	KASSERT(max_mcs <= RTWN_RIDX_LEGACY_HT_COUNT, ("increase ridx limit\n"));
 
 	/* Compute per-CCK rate Tx power. */
-	cckpow = rt->cck_tx_pwr[group];
 	for (ridx = RTWN_RIDX_CCK1; ridx <= RTWN_RIDX_CCK11; ridx++) {
-		power[ridx] = (ridx == RTWN_RIDX_CCK2) ? cckpow - 9 : cckpow;
+		/*
+		 * Note: the regulatory limit is applied to cckpow before
+		 * it's subtracted for CCK2.
+		 */
+		cckpow = rt->cck_tx_pwr[group];
+		if (cckpow > ic->ic_txpowlimit)
+			cckpow = ic->ic_txpowlimit;
+
+		/*
+		 * If it's CCK2 then we subtract the 9 (4.5dB?) offset
+		 * and make sure we aren't going to underflow.
+		 */
+		if (ridx == RTWN_RIDX_CCK2 && cckpow < 9)
+			cckpow = 0;
+		else if (ridx == RTWN_RIDX_CCK2)
+			cckpow = cckpow - 9;
+
+		power[ridx] = cckpow;
 	}
 
 	if (group < 5)
@@ -112,14 +134,18 @@
 
 	/* Compute per-OFDM rate Tx power. */
 	ofdmpow = htpow + rt->ofdm_tx_pwr_diff;
+	if (ofdmpow > ic->ic_txpowlimit)
+		ofdmpow = ic->ic_txpowlimit;
 	for (ridx = RTWN_RIDX_OFDM6; ridx <= RTWN_RIDX_OFDM54; ridx++)
 		power[ridx] = ofdmpow;
 
 	bw20pow = htpow + rt->bw20_tx_pwr_diff;
+	if (bw20pow > ic->ic_txpowlimit)
+		bw20pow = ic->ic_txpowlimit;
 	for (ridx = RTWN_RIDX_HT_MCS(0); ridx <= max_mcs; ridx++)
 		power[ridx] = bw20pow;
 
-	/* Apply max limit. */
+	/* Apply max limit */
 	for (ridx = RTWN_RIDX_CCK1; ridx <= max_mcs; ridx++) {
 		if (power[ridx] > R92C_MAX_TX_PWR)
 			power[ridx] = R92C_MAX_TX_PWR;
diff --git a/sys/dev/rtwn/rtl8188e/usb/r88eu_attach.c b/sys/dev/rtwn/rtl8188e/usb/r88eu_attach.c
--- a/sys/dev/rtwn/rtl8188e/usb/r88eu_attach.c
+++ b/sys/dev/rtwn/rtl8188e/usb/r88eu_attach.c
@@ -184,7 +184,7 @@
 	sc->sc_init_antsel		= rtwn_nop_softc;
 	sc->sc_post_init		= r88eu_post_init;
 	sc->sc_init_bcnq1_boundary	= rtwn_nop_int_softc;
-	sc->sc_set_tx_power		= rtwn_nop_int_softc_vap;
+	sc->sc_set_tx_power		= r92c_set_tx_power;
 
 	sc->mac_prog			= &rtl8188e_mac[0];
 	sc->mac_size			= nitems(rtl8188e_mac);
diff --git a/sys/dev/rtwn/rtl8192c/pci/r92ce_attach.c b/sys/dev/rtwn/rtl8192c/pci/r92ce_attach.c
--- a/sys/dev/rtwn/rtl8192c/pci/r92ce_attach.c
+++ b/sys/dev/rtwn/rtl8192c/pci/r92ce_attach.c
@@ -221,7 +221,7 @@
 	sc->sc_init_antsel		= rtwn_nop_softc;
 	sc->sc_post_init		= r92ce_post_init;
 	sc->sc_init_bcnq1_boundary	= rtwn_nop_int_softc;
-	sc->sc_set_tx_power		= rtwn_nop_int_softc_vap;
+	sc->sc_set_tx_power		= r92c_set_tx_power;
 
 	sc->mac_prog			= &rtl8192ce_mac[0];
 	sc->mac_size			= nitems(rtl8192ce_mac);
diff --git a/sys/dev/rtwn/rtl8192c/r92c.h b/sys/dev/rtwn/rtl8192c/r92c.h
--- a/sys/dev/rtwn/rtl8192c/r92c.h
+++ b/sys/dev/rtwn/rtl8192c/r92c.h
@@ -59,6 +59,7 @@
 	    struct ieee80211_channel *, uint8_t[RTWN_RIDX_COUNT]);
 void	r92c_write_txpower(struct rtwn_softc *, int,
 	    uint8_t power[RTWN_RIDX_COUNT]);
+int	r92c_set_tx_power(struct rtwn_softc *, struct ieee80211vap *);
 void	r92c_set_bw20(struct rtwn_softc *, uint8_t);
 void	r92c_set_chan(struct rtwn_softc *, struct ieee80211_channel *);
 void	r92c_set_gain(struct rtwn_softc *, uint8_t);
diff --git a/sys/dev/rtwn/rtl8192c/r92c_chan.c b/sys/dev/rtwn/rtl8192c/r92c_chan.c
--- a/sys/dev/rtwn/rtl8192c/r92c_chan.c
+++ b/sys/dev/rtwn/rtl8192c/r92c_chan.c
@@ -131,6 +131,7 @@
 r92c_get_txpower(struct rtwn_softc *sc, int chain,
     struct ieee80211_channel *c, uint8_t power[RTWN_RIDX_COUNT])
 {
+	const struct ieee80211com *ic = &sc->sc_ic;
 	struct r92c_softc *rs = sc->sc_priv;
 	struct rtwn_r92c_txpwr *rt = rs->rs_txpwr;
 	const struct rtwn_r92c_txagc *base = rs->rs_txagc;
@@ -144,7 +145,12 @@
 		return;
 	}
 
-	/* XXX net80211 regulatory */
+	/*
+	 * Treat the entries in 1/2 dBm resolution where 0 = 0dBm.
+	 * Apply the adjustments afterwards; assume that the vendor
+	 * driver is applying offsets to make up for the actual
+	 * target power in dBm.
+	 */
 
 	max_mcs = RTWN_RIDX_HT_MCS(sc->ntxchains * 8 - 1);
 	KASSERT(max_mcs <= RTWN_RIDX_LEGACY_HT_COUNT, ("increase ridx limit\n"));
@@ -199,6 +205,10 @@
 	for (ridx = RTWN_RIDX_CCK1; ridx <= max_mcs; ridx++) {
 		if (power[ridx] > R92C_MAX_TX_PWR)
 			power[ridx] = R92C_MAX_TX_PWR;
+		/* Apply net80211 limits */
+		if (power[ridx] > ic->ic_txpowlimit)
+			power[ridx] = ic->ic_txpowlimit;
+
 	}
 }
 
@@ -281,6 +291,25 @@
 	}
 }
 
+/*
+ * Only reconfigure the transmit power if there's a valid BSS node and
+ * channel.  Otherwise just let the next call to r92c_set_chan()
+ * configure the transmit power.
+ */
+int
+r92c_set_tx_power(struct rtwn_softc *sc, struct ieee80211vap *vap)
+{
+	if (vap->iv_bss == NULL)
+		return (EINVAL);
+	if (vap->iv_bss->ni_chan == IEEE80211_CHAN_ANYC)
+		return (EINVAL);
+
+	/* Set it for the current channel */
+	r92c_set_txpower(sc, vap->iv_bss->ni_chan);
+
+	return (0);
+}
+
 static void
 r92c_set_bw40(struct rtwn_softc *sc, uint8_t chan, int prichlo)
 {
diff --git a/sys/dev/rtwn/rtl8192c/usb/r92cu_attach.c b/sys/dev/rtwn/rtl8192c/usb/r92cu_attach.c
--- a/sys/dev/rtwn/rtl8192c/usb/r92cu_attach.c
+++ b/sys/dev/rtwn/rtl8192c/usb/r92cu_attach.c
@@ -213,7 +213,7 @@
 	sc->sc_init_antsel		= r92c_init_antsel;
 	sc->sc_post_init		= r92cu_post_init;
 	sc->sc_init_bcnq1_boundary	= rtwn_nop_int_softc;
-	sc->sc_set_tx_power		= rtwn_nop_int_softc_vap;
+	sc->sc_set_tx_power		= r92c_set_tx_power;
 
 	sc->mac_prog			= &rtl8192cu_mac[0];
 	sc->mac_size			= nitems(rtl8192cu_mac);
diff --git a/sys/dev/rtwn/rtl8192e/r92e.h b/sys/dev/rtwn/rtl8192e/r92e.h
--- a/sys/dev/rtwn/rtl8192e/r92e.h
+++ b/sys/dev/rtwn/rtl8192e/r92e.h
@@ -46,6 +46,7 @@
 
 /* r92e_chan.c */
 void	r92e_set_chan(struct rtwn_softc *, struct ieee80211_channel *);
+int	r92e_set_tx_power(struct rtwn_softc *sc, struct ieee80211vap *vap);
 
 /* r92e_fw.c */
 #ifndef RTWN_WITHOUT_UCODE
diff --git a/sys/dev/rtwn/rtl8192e/r92e_chan.c b/sys/dev/rtwn/rtl8192e/r92e_chan.c
--- a/sys/dev/rtwn/rtl8192e/r92e_chan.c
+++ b/sys/dev/rtwn/rtl8192e/r92e_chan.c
@@ -90,6 +90,7 @@
 r92e_get_txpower(struct rtwn_softc *sc, int chain, struct ieee80211_channel *c,
     uint8_t power[RTWN_RIDX_COUNT])
 {
+	const struct ieee80211com *ic = &sc->sc_ic;
 	struct r92e_softc *rs = sc->sc_priv;
 	int i, ridx, group, max_mcs;
 
@@ -103,19 +104,34 @@
 	max_mcs = RTWN_RIDX_HT_MCS(sc->ntxchains * 8 - 1);
 
 	/* XXX regulatory */
-	/* XXX net80211 regulatory */
 
-	for (ridx = RTWN_RIDX_CCK1; ridx <= RTWN_RIDX_CCK11; ridx++)
+	for (ridx = RTWN_RIDX_CCK1; ridx <= RTWN_RIDX_CCK11; ridx++) {
 		power[ridx] = rs->cck_tx_pwr[chain][group];
-	for (ridx = RTWN_RIDX_OFDM6; ridx <= max_mcs; ridx++)
+		if (power[ridx] > ic->ic_txpowlimit)
+			power[ridx] = ic->ic_txpowlimit;
+	}
+	for (ridx = RTWN_RIDX_OFDM6; ridx <= max_mcs; ridx++) {
 		power[ridx] = rs->ht40_tx_pwr_2g[chain][group];
+		if (power[ridx] > ic->ic_txpowlimit)
+			power[ridx] = ic->ic_txpowlimit;
+	}
+
+	for (ridx = RTWN_RIDX_OFDM6; ridx <= RTWN_RIDX_OFDM54; ridx++) {
+		/* Ensure we don't underflow if the power delta is -ve */
+		int8_t pwr_diff = rs->ofdm_tx_pwr_diff_2g[chain][0];
+		int8_t pwr;
 
-	for (ridx = RTWN_RIDX_OFDM6; ridx <= RTWN_RIDX_OFDM54; ridx++)
-		power[ridx] += rs->ofdm_tx_pwr_diff_2g[chain][0];
+		pwr = power[ridx] + pwr_diff;
+
+		if (pwr < 0)
+			pwr = 0;
+
+		power[ridx] = pwr;
+	}
 
 	for (i = 0; i < sc->ntxchains; i++) {
 		uint8_t min_mcs;
-		uint8_t pwr_diff;
+		int8_t pwr_diff, pwr;
 
 		if (IEEE80211_IS_CHAN_HT40(c))
 			pwr_diff = rs->bw40_tx_pwr_diff_2g[chain][i];
@@ -123,8 +139,13 @@
 			pwr_diff = rs->bw20_tx_pwr_diff_2g[chain][i];
 
 		min_mcs = RTWN_RIDX_HT_MCS(i * 8);
-		for (ridx = min_mcs; ridx <= max_mcs; ridx++)
-			power[ridx] += pwr_diff;
+		for (ridx = min_mcs; ridx <= max_mcs; ridx++) {
+			/* Ensure we don't underflow */
+			pwr = power[ridx] + pwr_diff;
+			if (pwr < 0)
+				pwr = 0;
+			power[ridx] = pwr;
+		}
 	}
 
 	/* Apply max limit. */
@@ -151,6 +172,19 @@
 	}
 }
 
+int
+r92e_set_tx_power(struct rtwn_softc *sc, struct ieee80211vap *vap)
+{
+
+	if (vap->iv_bss == NULL)
+		return (EINVAL);
+	if (vap->iv_bss->ni_chan == IEEE80211_CHAN_ANYC)
+		return (EINVAL);
+
+	r92e_set_txpower(sc, vap->iv_bss->ni_chan);
+	return (0);
+}
+
 static void
 r92e_set_bw40(struct rtwn_softc *sc, uint8_t chan, int prichlo)
 {
diff --git a/sys/dev/rtwn/rtl8192e/usb/r92eu_attach.c b/sys/dev/rtwn/rtl8192e/usb/r92eu_attach.c
--- a/sys/dev/rtwn/rtl8192e/usb/r92eu_attach.c
+++ b/sys/dev/rtwn/rtl8192e/usb/r92eu_attach.c
@@ -164,6 +164,7 @@
 	sc->sc_init_antsel		= rtwn_nop_softc;
 	sc->sc_post_init		= r92eu_post_init;
 	sc->sc_init_bcnq1_boundary	= rtwn_nop_int_softc;
+	sc->sc_set_tx_power		= r92e_set_tx_power;
 
 	sc->mac_prog			= &rtl8192eu_mac[0];
 	sc->mac_size			= nitems(rtl8192eu_mac);