diff --git a/drivers/isdn/hisax/isar.c b/drivers/isdn/hisax/isar.c
index 6f1a6583b17d..9df9e3548cf1 100644
--- a/drivers/isdn/hisax/isar.c
+++ b/drivers/isdn/hisax/isar.c
@@ -431,7 +431,6 @@ reterror:
 	return(ret);
 }
 
-extern void BChannel_bh(struct BCState *);
 #define B_LL_NOCARRIER	8
 #define B_LL_CONNECT	9
 #define B_LL_OK		10
diff --git a/drivers/isdn/hisax/isdnl1.h b/drivers/isdn/hisax/isdnl1.h
index 0e88cfabdf10..172ad4c8c961 100644
--- a/drivers/isdn/hisax/isdnl1.h
+++ b/drivers/isdn/hisax/isdnl1.h
@@ -21,12 +21,11 @@
 #define B_XMTBUFREADY	1
 #define B_ACKPENDING	2
 
-extern void debugl1(struct IsdnCardState *cs, char *fmt, ...);
-extern void DChannel_proc_xmt(struct IsdnCardState *cs);
-extern void DChannel_proc_rcv(struct IsdnCardState *cs);
-extern void l1_msg(struct IsdnCardState *cs, int pr, void *arg);
-extern void l1_msg_b(struct PStack *st, int pr, void *arg);
-
-#ifdef L2FRAME_DEBUG
-extern void Logl2Frame(struct IsdnCardState *cs, struct sk_buff *skb, char *buf, int dir);
-#endif
+void debugl1(struct IsdnCardState *cs, char *fmt, ...);
+void DChannel_proc_xmt(struct IsdnCardState *cs);
+void DChannel_proc_rcv(struct IsdnCardState *cs);
+void l1_msg(struct IsdnCardState *cs, int pr, void *arg);
+void l1_msg_b(struct PStack *st, int pr, void *arg);
+void Logl2Frame(struct IsdnCardState *cs, struct sk_buff *skb, char *buf,
+		int dir);
+void BChannel_bh(struct work_struct *work);
diff --git a/drivers/isdn/hisax/isdnl3.c b/drivers/isdn/hisax/isdnl3.c
index 281fa27d9f00..935f23356fae 100644
--- a/drivers/isdn/hisax/isdnl3.c
+++ b/drivers/isdn/hisax/isdnl3.c
@@ -231,18 +231,6 @@ no_l3_proto_spec(struct PStack *st, isdn_ctrl *ic)
 	return(-1);
 }
 
-#ifdef	CONFIG_HISAX_EURO
-extern void setstack_dss1(struct PStack *st);
-#endif
-
-#ifdef  CONFIG_HISAX_NI1
-extern void setstack_ni1(struct PStack *st);
-#endif
-
-#ifdef	CONFIG_HISAX_1TR6
-extern void setstack_1tr6(struct PStack *st);
-#endif
-
 struct l3_process
 *getl3proc(struct PStack *st, int cr)
 {
diff --git a/drivers/isdn/hisax/isdnl3.h b/drivers/isdn/hisax/isdnl3.h
index 1dbe0297a506..749498fe6c4b 100644
--- a/drivers/isdn/hisax/isdnl3.h
+++ b/drivers/isdn/hisax/isdnl3.h
@@ -25,13 +25,19 @@ struct stateentry {
 
 #define l3_debug(st, fmt, args...) HiSax_putstatus(st->l1.hardware, "l3 ", fmt, ## args)
 
-extern void newl3state(struct l3_process *pc, int state);
-extern void L3InitTimer(struct l3_process *pc, struct L3Timer *t);
-extern void L3DelTimer(struct L3Timer *t);
-extern int L3AddTimer(struct L3Timer *t, int millisec, int event);
-extern void StopAllL3Timer(struct l3_process *pc);
-extern struct sk_buff *l3_alloc_skb(int len);
-extern struct l3_process *new_l3_process(struct PStack *st, int cr);
-extern void release_l3_process(struct l3_process *p);
-extern struct l3_process *getl3proc(struct PStack *st, int cr);
-extern void l3_msg(struct PStack *st, int pr, void *arg);
+struct PStack;
+
+void newl3state(struct l3_process *pc, int state);
+void L3InitTimer(struct l3_process *pc, struct L3Timer *t);
+void L3DelTimer(struct L3Timer *t);
+int L3AddTimer(struct L3Timer *t, int millisec, int event);
+void StopAllL3Timer(struct l3_process *pc);
+struct sk_buff *l3_alloc_skb(int len);
+struct l3_process *new_l3_process(struct PStack *st, int cr);
+void release_l3_process(struct l3_process *p);
+struct l3_process *getl3proc(struct PStack *st, int cr);
+void l3_msg(struct PStack *st, int pr, void *arg);
+void setstack_dss1(struct PStack *st);
+void setstack_ni1(struct PStack *st);
+void setstack_1tr6(struct PStack *st);
+