diff --git a/sys/dev/rtwn/rtl8188e/r88e.h b/sys/dev/rtwn/rtl8188e/r88e.h
--- a/sys/dev/rtwn/rtl8188e/r88e.h
+++ b/sys/dev/rtwn/rtl8188e/r88e.h
@@ -21,6 +21,8 @@
 #ifndef RTL8188E_H
 #define RTL8188E_H
 
+#include <dev/rtwn/if_rtwn_ridx.h>
+
 /*
  * Global definitions.
  */
@@ -46,7 +48,7 @@
 
 /* r88e_chan.c */
 void	r88e_get_txpower(struct rtwn_softc *, int,
-	    struct ieee80211_channel *, uint8_t[]);
+	    struct ieee80211_channel *, uint8_t[RTWN_RIDX_COUNT]);
 void	r88e_set_bw20(struct rtwn_softc *, uint8_t);
 void	r88e_set_gain(struct rtwn_softc *, uint8_t);
 
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
@@ -21,6 +21,8 @@
 #ifndef RTL8192C_H
 #define RTL8192C_H
 
+#include <dev/rtwn/if_rtwn_ridx.h>
+
 /*
  * Global definitions.
  */
@@ -54,9 +56,9 @@
 
 /* r92c_chan.c */
 void	r92c_get_txpower(struct rtwn_softc *, int,
-	    struct ieee80211_channel *, uint8_t[]);
+	    struct ieee80211_channel *, uint8_t[RTWN_RIDX_COUNT]);
 void	r92c_write_txpower(struct rtwn_softc *, int,
-	    uint8_t power[]);
+	    uint8_t power[RTWN_RIDX_COUNT]);
 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);