erts: Remove undocumented driver_event

24 files changed, 60 insertions, 1014 deletions

diff --git a/erts/doc/src/driver_entry.xml b/erts/doc/src/driver_entry.xml
index 2421e0a8d9..e8c7e26457 100644
--- a/erts/doc/src/driver_entry.xml
+++ b/erts/doc/src/driver_entry.xml
@@ -196,10 +196,7 @@ typedef struct erl_drv_entry {
 			 char **rbuf, ErlDrvSizeT rlen, unsigned int *flags);
                                 /* Works mostly like 'control', a synchronous
                                    call into the driver */
-    void (*event)(ErlDrvData drv_data, ErlDrvEvent event,
-                  ErlDrvEventData event_data);
-                                /* Called when an event selected by
-                                   driver_event() has occurred */
+    void* unused_event_callback;
     int extended_marker;        /* ERL_DRV_EXTENDED_MARKER */
     int major_version;          /* ERL_DRV_EXTENDED_MAJOR_VERSION */
     int minor_version;          /* ERL_DRV_EXTENDED_MINOR_VERSION */
diff --git a/erts/emulator/beam/erl_alloc.c b/erts/emulator/beam/erl_alloc.c
index 845cef24c7..1c365f906b 100644
--- a/erts/emulator/beam/erl_alloc.c
+++ b/erts/emulator/beam/erl_alloc.c
@@ -644,8 +644,6 @@ erts_alloc_init(int *argc, char **argv, ErtsAllocInitOpts *eaiop)
 	= ERTS_MONITOR_SH_SIZE * sizeof(Uint);
     fix_type_sizes[ERTS_ALC_FIX_TYPE_IX(ERTS_ALC_T_NLINK_SH)]
 	= ERTS_LINK_SH_SIZE * sizeof(Uint);
-    fix_type_sizes[ERTS_ALC_FIX_TYPE_IX(ERTS_ALC_T_DRV_EV_D_STATE)]
-	= sizeof(ErtsDrvEventDataState);
     fix_type_sizes[ERTS_ALC_FIX_TYPE_IX(ERTS_ALC_T_DRV_SEL_D_STATE)]
 	= sizeof(ErtsDrvSelectDataState);
     fix_type_sizes[ERTS_ALC_FIX_TYPE_IX(ERTS_ALC_T_NIF_SEL_D_STATE)]
diff --git a/erts/emulator/beam/erl_alloc.types b/erts/emulator/beam/erl_alloc.types
index 11884299e2..3ec1389d47 100644
--- a/erts/emulator/beam/erl_alloc.types
+++ b/erts/emulator/beam/erl_alloc.types
@@ -351,7 +351,6 @@ type	SYS_CHECK_REQ	SHORT_LIVED	SYSTEM		system_check_request
 type  	TEMP_TERM 	TEMPORARY	SYSTEM		temp_term
 type	DRV_TAB		LONG_LIVED	SYSTEM		drv_tab
 type	DRV_EV_STATE	LONG_LIVED	SYSTEM		driver_event_state
-type	DRV_EV_D_STATE	FIXED_SIZE	SYSTEM		driver_event_data_state
 type	DRV_SEL_D_STATE	FIXED_SIZE	SYSTEM		driver_select_data_state
 type	NIF_SEL_D_STATE	FIXED_SIZE	SYSTEM		enif_select_data_state
 type	FD_LIST		SHORT_LIVED	SYSTEM		fd_list
diff --git a/erts/emulator/beam/erl_bif_info.c b/erts/emulator/beam/erl_bif_info.c
index d296e794d5..3b6e83c242 100644
--- a/erts/emulator/beam/erl_bif_info.c
+++ b/erts/emulator/beam/erl_bif_info.c
@@ -3574,15 +3574,13 @@ BIF_RETTYPE erts_debug_get_internal_state_1(BIF_ALIST_1)
 	    szp = &sz;
 	    hpp = NULL;
 	    while (1) {
-		res = erts_bld_tuple(hpp, szp, 4,
+		res = erts_bld_tuple(hpp, szp, 3,
 				     erts_bld_uint(hpp, szp,
 						   (Uint) no_errors),
 				     erts_bld_uint(hpp, szp,
 						   (Uint) ciodi.no_used_fds),
 				     erts_bld_uint(hpp, szp,
-						   (Uint) ciodi.no_driver_select_structs),
-				     erts_bld_uint(hpp, szp,
-						   (Uint) ciodi.no_driver_event_structs));
+						   (Uint) ciodi.no_driver_select_structs));
 		if (hpp)
 		    break;
 		hp = HAlloc(BIF_P, sz);
diff --git a/erts/emulator/beam/erl_driver.h b/erts/emulator/beam/erl_driver.h
index 5ad616fec3..d5379a40d5 100644
--- a/erts/emulator/beam/erl_driver.h
+++ b/erts/emulator/beam/erl_driver.h
@@ -148,14 +148,6 @@ typedef struct _erl_drv_event* ErlDrvEvent; /* An event to be selected on. */
 typedef struct _erl_drv_port* ErlDrvPort; /* A port descriptor. */
 typedef struct _erl_drv_port* ErlDrvThreadData; /* Thread data. */
 
-#if !defined(__WIN32__) && !defined(_WIN32) && !defined(_WIN32_) && !defined(USE_SELECT)
-struct erl_drv_event_data {
-    short events;
-    short revents;
-};
-#endif
-typedef struct erl_drv_event_data *ErlDrvEventData; /* Event data */
-
 typedef struct {
     unsigned long megasecs;
     unsigned long secs;
@@ -270,10 +262,7 @@ typedef struct erl_drv_entry {
 			 unsigned int *flags); /* Works mostly like 'control',
 						  a synchronous
 						  call into the driver. */
-    void (*event)(ErlDrvData drv_data, ErlDrvEvent event,
-		  ErlDrvEventData event_data);
-                                /* Called when an event selected by 
-				   driver_event() has occurred */
+    void (*unused_event_callback)(void);
     int extended_marker;	/* ERL_DRV_EXTENDED_MARKER */
     int major_version;		/* ERL_DRV_EXTENDED_MAJOR_VERSION */
     int minor_version;		/* ERL_DRV_EXTENDED_MINOR_VERSION */
@@ -340,8 +329,6 @@ EXTERN void erl_drv_busy_msgq_limits(ErlDrvPort port,
 				     ErlDrvSizeT *high);
 
 EXTERN int driver_select(ErlDrvPort port, ErlDrvEvent event, int mode, int on);
-EXTERN int driver_event(ErlDrvPort port, ErlDrvEvent event, 
-			ErlDrvEventData event_data);
 
 EXTERN int driver_output(ErlDrvPort port, char *buf, ErlDrvSizeT len);
 EXTERN int driver_output2(ErlDrvPort port, char *hbuf, ErlDrvSizeT hlen,
diff --git a/erts/emulator/beam/erl_lock_count.c b/erts/emulator/beam/erl_lock_count.c
index d2e8f47d59..11890e44d1 100644
--- a/erts/emulator/beam/erl_lock_count.c
+++ b/erts/emulator/beam/erl_lock_count.c
@@ -593,16 +593,14 @@ void erts_lcnt_set_category_mask(erts_lock_flags_t mask) {
 #ifdef ERTS_ENABLE_KERNEL_POLL
         if(erts_use_kernel_poll) {
             erts_lcnt_update_pollset_locks_kp(mask & ERTS_LOCK_FLAGS_CATEGORY_IO);
-            erts_lcnt_update_cio_locks_kp(mask & ERTS_LOCK_FLAGS_CATEGORY_IO);
         } else {
             erts_lcnt_update_pollset_locks_nkp(mask & ERTS_LOCK_FLAGS_CATEGORY_IO);
-            erts_lcnt_update_cio_locks_nkp(mask & ERTS_LOCK_FLAGS_CATEGORY_IO);
         }
 #else
         erts_lcnt_update_pollset_locks(mask & ERTS_LOCK_FLAGS_CATEGORY_IO);
-        erts_lcnt_update_cio_locks(mask & ERTS_LOCK_FLAGS_CATEGORY_IO);
 #endif
 
+        erts_lcnt_update_cio_locks(mask & ERTS_LOCK_FLAGS_CATEGORY_IO);
         erts_lcnt_update_driver_locks(mask & ERTS_LOCK_FLAGS_CATEGORY_IO);
         erts_lcnt_update_port_locks(mask & ERTS_LOCK_FLAGS_CATEGORY_IO);
     }
diff --git a/erts/emulator/beam/erl_port_task.c b/erts/emulator/beam/erl_port_task.c
index b9152a7b5e..bdce811847 100644
--- a/erts/emulator/beam/erl_port_task.c
+++ b/erts/emulator/beam/erl_port_task.c
@@ -100,7 +100,6 @@ erts_atomic_t erts_port_task_outstanding_io_tasks;
 typedef union {
     struct { /* I/O tasks */
 	ErlDrvEvent event;
-	ErlDrvEventData event_data;
     } io;
     struct {
 	ErtsProc2PortSigCallback callback;
@@ -1315,7 +1314,6 @@ erts_port_task_abort(ErtsPortTaskHandle *pthp)
 	    switch (ptp->type) {
 	    case ERTS_PORT_TASK_INPUT:
 	    case ERTS_PORT_TASK_OUTPUT:
-	    case ERTS_PORT_TASK_EVENT:
 		ASSERT(erts_atomic_read_nob(
 			   &erts_port_task_outstanding_io_tasks) > 0);
 		erts_atomic_dec_relb(&erts_port_task_outstanding_io_tasks);
@@ -1463,15 +1461,6 @@ erts_port_task_schedule(Eterm id,
 	erts_atomic_inc_relb(&erts_port_task_outstanding_io_tasks);
 	break;
     }
-    case ERTS_PORT_TASK_EVENT: {
-	va_list argp;
-	va_start(argp, type);
-	ptp->u.alive.td.io.event = va_arg(argp, ErlDrvEvent);
-	ptp->u.alive.td.io.event_data = va_arg(argp, ErlDrvEventData);
-	va_end(argp);
-	erts_atomic_inc_relb(&erts_port_task_outstanding_io_tasks);
-	break;
-    }
     case ERTS_PORT_TASK_PROC_SIG: {
 	va_list argp;
 	va_start(argp, type);
@@ -1769,17 +1758,6 @@ erts_port_task_execute(ErtsRunQueue *runq, Port **curr_port_pp)
 	    reset_executed_io_task_handle(ptp);
 	    io_tasks_executed++;
 	    break;
-	case ERTS_PORT_TASK_EVENT:
-	    reds = ERTS_PORT_REDS_EVENT;
-	    ASSERT((state & ERTS_PORT_SFLGS_DEAD) == 0);
-            DTRACE_DRIVER(driver_event, pp);
-            LTTNG_DRIVER(driver_event, pp);
-	    (*pp->drv_ptr->event)((ErlDrvData) pp->drv_data,
-				  ptp->u.alive.td.io.event,
-				  ptp->u.alive.td.io.event_data);
-	    reset_executed_io_task_handle(ptp);
-	    io_tasks_executed++;
-	    break;
 	case ERTS_PORT_TASK_PROC_SIG: {
 	    ErtsProc2PortSigData *sigdp = &ptp->u.alive.td.psig.data;
 	    reset_handle(ptp);
@@ -2032,13 +2010,6 @@ begin_port_cleanup(Port *pp, ErtsPortTask **execqp, int *processing_busy_q_p)
 				      DO_WRITE,
 				      1);
 		break;
-	    case ERTS_PORT_TASK_EVENT:
-		erts_stale_drv_select(pp->common.id,
-				      ERTS_Port2ErlDrvPort(pp),
-				      ptp->u.alive.td.io.event,
-				      0,
-				      1);
-		break;
 	    case ERTS_PORT_TASK_DIST_CMD:
 		break;
 	    case ERTS_PORT_TASK_PROC_SIG: {
diff --git a/erts/emulator/beam/erl_port_task.h b/erts/emulator/beam/erl_port_task.h
index 561f4ca936..ffd42c9bab 100644
--- a/erts/emulator/beam/erl_port_task.h
+++ b/erts/emulator/beam/erl_port_task.h
@@ -56,7 +56,6 @@ typedef erts_atomic_t ErtsPortTaskHandle;
 typedef enum {
     ERTS_PORT_TASK_INPUT,
     ERTS_PORT_TASK_OUTPUT,
-    ERTS_PORT_TASK_EVENT,
     ERTS_PORT_TASK_TIMEOUT,
     ERTS_PORT_TASK_DIST_CMD,
     ERTS_PORT_TASK_PROC_SIG
diff --git a/erts/emulator/beam/erl_threads.h b/erts/emulator/beam/erl_threads.h
index e306df818d..aedceb6fc2 100644
--- a/erts/emulator/beam/erl_threads.h
+++ b/erts/emulator/beam/erl_threads.h
@@ -454,7 +454,6 @@ ERTS_GLB_INLINE void erts_rwmtx_runlock(erts_rwmtx_t *rwmtx);
 ERTS_GLB_INLINE void erts_rwmtx_rwunlock(erts_rwmtx_t *rwmtx);
 ERTS_GLB_INLINE int erts_lc_rwmtx_is_rlocked(erts_rwmtx_t *mtx);
 ERTS_GLB_INLINE int erts_lc_rwmtx_is_rwlocked(erts_rwmtx_t *mtx);
-
 ERTS_GLB_INLINE void erts_spinlock_init(erts_spinlock_t *lock,
                                         char *name,
                                         Eterm extra,
diff --git a/erts/emulator/beam/erl_trace.c b/erts/emulator/beam/erl_trace.c
index a07e3642f6..4b996d8fc2 100644
--- a/erts/emulator/beam/erl_trace.c
+++ b/erts/emulator/beam/erl_trace.c
@@ -1449,7 +1449,6 @@ monitor_long_schedule_port(Port *pp, ErtsPortTaskType type, Uint time)
     case ERTS_PORT_TASK_TIMEOUT: op = am_timeout; break;
     case ERTS_PORT_TASK_INPUT: op = am_input; break;
     case ERTS_PORT_TASK_OUTPUT: op = am_output; break;
-    case ERTS_PORT_TASK_EVENT: op = am_event; break;
     case ERTS_PORT_TASK_DIST_CMD: op = am_dist_cmd; break;
     default: op = am_undefined; break;
     }
diff --git a/erts/emulator/beam/erlang_lttng.h b/erts/emulator/beam/erlang_lttng.h
index 4e869671f7..feb05f4f4c 100644
--- a/erts/emulator/beam/erlang_lttng.h
+++ b/erts/emulator/beam/erlang_lttng.h
@@ -159,21 +159,6 @@ TRACEPOINT_EVENT(
 
 TRACEPOINT_EVENT(
     org_erlang_otp,
-    driver_event,
-    TP_ARGS(
-        char*, pid,
-        char*, port,
-        char*, driver
-    ),
-    TP_FIELDS(
-        ctf_string(pid, pid)
-        ctf_string(port, port)
-        ctf_string(driver, driver)
-    )
-)
-
-TRACEPOINT_EVENT(
-    org_erlang_otp,
     driver_timeout,
     TP_ARGS(
         char*, pid,
diff --git a/erts/emulator/beam/global.h b/erts/emulator/beam/global.h
index 2b0ad0b98a..c3f8e92f13 100644
--- a/erts/emulator/beam/global.h
+++ b/erts/emulator/beam/global.h
@@ -222,8 +222,6 @@ struct erts_driver_t_ {
 			 char *buf, ErlDrvSizeT len,
 			 char **rbuf, ErlDrvSizeT rlen, /* Might be NULL */
 			 unsigned int *flags);
-    void (*event)(ErlDrvData drv_data, ErlDrvEvent event,
-		  ErlDrvEventData event_data);
     void (*ready_input)(ErlDrvData drv_data, ErlDrvEvent event); 
     void (*ready_output)(ErlDrvData drv_data, ErlDrvEvent event);  
     void (*timeout)(ErlDrvData drv_data);
diff --git a/erts/emulator/beam/io.c b/erts/emulator/beam/io.c
index bc1b9b6ef4..85013af3ad 100644
--- a/erts/emulator/beam/io.c
+++ b/erts/emulator/beam/io.c
@@ -5390,24 +5390,17 @@ erts_stale_drv_select(Eterm port,
     switch (mode) {
     case ERL_DRV_READ | ERL_DRV_WRITE:
 	type = "Input/Output";
-	goto deselect;
     case ERL_DRV_WRITE:
 	type = "Output";
-	goto deselect;
     case ERL_DRV_READ:
 	type = "Input";
-    deselect:
-	if (deselect) {
-	    driver_select(drv_port, hndl,
-			  mode | ERL_DRV_USE_NO_CALLBACK,
-			  0);
-	}
-	break;
     default:
-	type = "Event";
-	if (deselect)
-	    driver_event(drv_port, hndl, NULL);
-	break;
+        type = "";
+    }
+    if (deselect) {
+        driver_select(drv_port, hndl,
+                      mode | ERL_DRV_USE_NO_CALLBACK,
+                      0);
     }
 
     dsbufp = erts_create_logger_dsbuf();
@@ -7511,14 +7504,6 @@ no_output_callback(ErlDrvData drv_data, char *buf, ErlDrvSizeT len)
 }
 
 static void
-no_event_callback(ErlDrvData drv_data, ErlDrvEvent event, ErlDrvEventData event_data)
-{
-    Port *prt = get_current_port();
-    report_missing_drv_callback(prt, "Event", "event()");
-    driver_event(ERTS_Port2ErlDrvPort(prt), event, NULL);
-}
-
-static void
 no_ready_input_callback(ErlDrvData drv_data, ErlDrvEvent event)
 {
     Port *prt = get_current_port();
@@ -7585,7 +7570,6 @@ init_driver(erts_driver_t *drv, ErlDrvEntry *de, DE_Handle *handle)
     drv->outputv = de->outputv;
     drv->control = de->control;
     drv->call = de->call;
-    drv->event = de->event ? de->event : no_event_callback;
     drv->ready_input = de->ready_input ? de->ready_input : no_ready_input_callback;
     drv->ready_output = de->ready_output ? de->ready_output : no_ready_output_callback;
     drv->timeout = de->timeout ? de->timeout : no_timeout_callback;
diff --git a/erts/emulator/beam/sys.h b/erts/emulator/beam/sys.h
index 3dd6ef333b..e2a21c0ecd 100644
--- a/erts/emulator/beam/sys.h
+++ b/erts/emulator/beam/sys.h
@@ -790,7 +790,6 @@ void fini_getenv_state(GETENV_STATE *);
 typedef struct {
     int no_used_fds;
     int no_driver_select_structs;
-    int no_driver_event_structs;
 } ErtsCheckIoDebugInfo;
 int erts_check_io_debug(ErtsCheckIoDebugInfo *ip);
 
diff --git a/erts/emulator/sys/common/erl_check_io.c b/erts/emulator/sys/common/erl_check_io.c
index bed815c64b..cd695e236f 100644
--- a/erts/emulator/sys/common/erl_check_io.c
+++ b/erts/emulator/sys/common/erl_check_io.c
@@ -52,10 +52,9 @@
 typedef char EventStateType;
 #define ERTS_EV_TYPE_NONE     ((EventStateType) 0)
 #define ERTS_EV_TYPE_DRV_SEL  ((EventStateType) 1) /* driver_select */
-#define ERTS_EV_TYPE_DRV_EV   ((EventStateType) 2) /* driver_event */
-#define ERTS_EV_TYPE_STOP_USE ((EventStateType) 3) /* pending stop_select */
-#define ERTS_EV_TYPE_NIF      ((EventStateType) 4) /* enif_select */
-#define ERTS_EV_TYPE_STOP_NIF ((EventStateType) 5) /* pending nif stop */
+#define ERTS_EV_TYPE_STOP_USE ((EventStateType) 2) /* pending stop_select */
+#define ERTS_EV_TYPE_NIF      ((EventStateType) 3) /* enif_select */
+#define ERTS_EV_TYPE_STOP_NIF ((EventStateType) 4) /* pending nif stop */
 
 typedef char EventStateFlags;
 #define ERTS_EV_FLAG_USED         ((EventStateFlags) 1)   /* ERL_DRV_USE has been turned on */
@@ -78,9 +77,6 @@ typedef char EventStateFlags;
 #  define ERTS_CIO_EXPORT(FUNC) FUNC
 #endif
 
-#define ERTS_CIO_HAVE_DRV_EVENT \
-  (ERTS_POLL_USE_POLL && !ERTS_POLL_USE_KERNEL_POLL)
-
 #define ERTS_CIO_POLL_CTL	ERTS_POLL_EXPORT(erts_poll_control)
 #define ERTS_CIO_POLL_CTLV	ERTS_POLL_EXPORT(erts_poll_controlv)
 #define ERTS_CIO_POLL_WAIT	ERTS_POLL_EXPORT(erts_poll_wait)
@@ -116,7 +112,6 @@ void erts_init_check_io_kp(void);
 void erts_init_check_io_nkp(void);
 int ERTS_CIO_EXPORT(driver_select)(ErlDrvPort, ErlDrvEvent, int, int);
 int ERTS_CIO_EXPORT(enif_select)(ErlNifEnv*, ErlNifEvent, enum ErlNifSelectFlags, void*, const ErlNifPid*, Eterm);
-int ERTS_CIO_EXPORT(driver_event)(ErlDrvPort, ErlDrvEvent, ErlDrvEventData);
 Uint ERTS_CIO_EXPORT(erts_check_io_size)(void);
 Eterm ERTS_CIO_EXPORT(erts_check_io_info)(void *);
 int ERTS_CIO_EXPORT(erts_check_io_max_files)(void);
@@ -124,6 +119,9 @@ void ERTS_CIO_EXPORT(erts_check_io_interrupt)(int);
 void ERTS_CIO_EXPORT(erts_check_io_interrupt_timed)(int, ErtsMonotonicTime);
 void ERTS_CIO_EXPORT(erts_check_io)(int);
 int ERTS_CIO_EXPORT(erts_check_io_debug)(ErtsCheckIoDebugInfo *);
+#ifdef ERTS_ENABLE_LOCK_COUNT
+void ERTS_CIO_EXPORT(erts_lcnt_update_cio_locks)(int enable);
+#endif
 #endif
 
 
@@ -134,9 +132,6 @@ typedef struct {
     ErtsSysFdType fd;
     struct {
 	ErtsDrvSelectDataState *select;   /* ERTS_EV_TYPE_DRV_SEL */
-#if ERTS_CIO_HAVE_DRV_EVENT
-	ErtsDrvEventDataState *event;     /* ERTS_EV_TYPE_DRV_EV */
-#endif
         ErtsNifSelectDataState *nif;      /* ERTS_EV_TYPE_NIF */
         union {
             erts_driver_t*  drv_ptr;    /* ERTS_EV_TYPE_STOP_USE */
@@ -205,9 +200,6 @@ static ERTS_INLINE ErtsDrvEventState* hash_new_drv_ev_state(ErtsSysFdType fd)
     ErtsDrvEventState tmpl;
     tmpl.fd = fd;
     tmpl.driver.select = NULL;
-#if ERTS_CIO_HAVE_DRV_EVENT
-    tmpl.driver.event = NULL;
-#endif
     tmpl.driver.nif = NULL;
     tmpl.driver.stop.drv_ptr = NULL;
     tmpl.events = 0;
@@ -240,15 +232,6 @@ static void print_nif_select_op(erts_dsprintf_buf_t*, ErtsSysFdType,
 static void drv_select_large_fd_error(ErlDrvPort, ErtsSysFdType, int, int);
 static void nif_select_large_fd_error(ErtsSysFdType, int, ErtsResource*,Eterm ref);
 #endif
-#if ERTS_CIO_HAVE_DRV_EVENT
-static void drv_event_steal(ErlDrvPort ix, ErtsDrvEventState *state,
-			ErlDrvEventData event_data);
-static void print_drv_event_op(erts_dsprintf_buf_t *dsbufp,
-                               ErlDrvPort, ErtsSysFdType, ErlDrvEventData);
-#ifdef ERTS_SYS_CONTINOUS_FD_NUMBERS
-static void event_large_fd_error(ErlDrvPort, ErtsSysFdType, ErlDrvEventData);
-#endif
-#endif
 static void
 steal_pending_stop_use(erts_dsprintf_buf_t*, ErlDrvPort, ErtsDrvEventState*,
                        int mode, int on);
@@ -313,32 +296,6 @@ free_nif_select_data(ErtsNifSelectDataState *dsp)
     erts_free(ERTS_ALC_T_NIF_SEL_D_STATE, dsp);
 }
 
-#if ERTS_CIO_HAVE_DRV_EVENT
-
-static ERTS_INLINE ErtsDrvEventDataState *
-alloc_drv_event_data(void)
-{
-    ErtsDrvEventDataState *dep = erts_alloc(ERTS_ALC_T_DRV_EV_D_STATE,
-					    sizeof(ErtsDrvEventDataState));
-    dep->port = NIL;
-    dep->data = NULL;
-    dep->removed_events = 0;
-#if ERTS_CIO_DEFER_ACTIVE_EVENTS
-    dep->deferred_events = 0;
-#endif
-    init_iotask(&dep->iotask);
-    return dep;
-}
-
-static ERTS_INLINE void
-free_drv_event_data(ErtsDrvEventDataState *dep)
-{
-    ASSERT(!erts_port_task_is_scheduled(&dep->iotask.task));
-    erts_free(ERTS_ALC_T_DRV_EV_D_STATE, dep);   
-}
-
-#endif /* ERTS_CIO_HAVE_DRV_EVENT */
-
 static ERTS_INLINE void
 remember_removed(ErtsDrvEventState *state, struct pollset_info* psi)
 {
@@ -432,7 +389,6 @@ forget_removed(struct pollset_info* psi)
 #endif
 		break;
 	    case ERTS_EV_TYPE_DRV_SEL:
-	    case ERTS_EV_TYPE_DRV_EV:
 		break;
 	    default:
 		ASSERT(0);
@@ -487,9 +443,6 @@ grow_drv_ev_state(int min_ix)
 	for (i = old_len; i < new_len; i++) {
 	    drv_ev_state[i].fd = (ErtsSysFdType) i;
 	    drv_ev_state[i].driver.select = NULL;
-#if ERTS_CIO_HAVE_DRV_EVENT
-	    drv_ev_state[i].driver.event = NULL;
-#endif
 	    drv_ev_state[i].driver.stop.drv_ptr = NULL;
             drv_ev_state[i].driver.nif = NULL;
 	    drv_ev_state[i].events = 0;
@@ -524,13 +477,6 @@ abort_tasks(ErtsDrvEventState *state, int mode)
     switch (mode) {
     case 0: check_type:
 	switch (state->type) {
-#if ERTS_CIO_HAVE_DRV_EVENT
-	case ERTS_EV_TYPE_DRV_EV:
-	    abort_task(state->driver.event->port,
-		       &state->driver.event->iotask.task,
-		       ERTS_EV_TYPE_DRV_EV);
-	    return;
-#endif
         case ERTS_EV_TYPE_NIF:
 	case ERTS_EV_TYPE_NONE:
 	    return;
@@ -598,13 +544,6 @@ deselect(ErtsDrvEventState *state, int mode)
 	    state->driver.select->inport = NIL;
 	    state->driver.select->outport = NIL;
 	    break;
-#if ERTS_CIO_HAVE_DRV_EVENT
-	case ERTS_EV_TYPE_DRV_EV:
-	    state->driver.event->port = NIL;
-	    state->driver.event->data = NULL;
-	    state->driver.event->removed_events = (ErtsPollEvents) 0;
-	    break;
-#endif
 	case ERTS_EV_TYPE_NONE:
 	    break;
 	default:
@@ -626,9 +565,6 @@ deselect(ErtsDrvEventState *state, int mode)
 
 static ERTS_INLINE void
 check_fd_cleanup(ErtsDrvEventState *state,
-#if ERTS_CIO_HAVE_DRV_EVENT
-		 ErtsDrvEventDataState **free_event,
-#endif
 		 ErtsDrvSelectDataState **free_select,
                  ErtsNifSelectDataState **free_nif)
 {
@@ -653,23 +589,9 @@ check_fd_cleanup(ErtsDrvEventState *state,
         state->driver.nif = NULL;
     }
 
-#if ERTS_CIO_HAVE_DRV_EVENT
-    *free_event = NULL;
-    if (state->driver.event
-	&& (state->type != ERTS_EV_TYPE_DRV_EV)
-	&& !is_iotask_active(&state->driver.event->iotask,  current_cio_time)) {
-	
-	*free_event = state->driver.event;
-	state->driver.event = NULL;
-    }
-#endif
-
 #ifndef ERTS_SYS_CONTINOUS_FD_NUMBERS
     if (((state->type != ERTS_EV_TYPE_NONE)
 	 | state->remove_cnt
-#if ERTS_CIO_HAVE_DRV_EVENT
-	 | (state->driver.event != NULL)
-#endif
 	 | (state->driver.select != NULL)) == 0) {
 
 	hash_erase_drv_ev_state(state);
@@ -692,9 +614,6 @@ check_cleanup_active_fd(ErtsSysFdType fd,
     erts_mtx_t *mtx = fd_mtx(fd);
     void *free_select = NULL;
     void *free_nif = NULL;
-#if ERTS_CIO_HAVE_DRV_EVENT
-    void *free_event = NULL;
-#endif
 #if ERTS_CIO_DEFER_ACTIVE_EVENTS
     ErtsPollEvents evon = 0, evoff = 0;
 #endif
@@ -784,35 +703,6 @@ check_cleanup_active_fd(ErtsSysFdType fd,
             }
         }
 
-#if ERTS_CIO_HAVE_DRV_EVENT
-	if (state->driver.event) {
-	    if (is_iotask_active(&state->driver.event->iotask, current_cio_time)) {
-#if ERTS_CIO_DEFER_ACTIVE_EVENTS
-		ErtsPollEvents evs = state->events & ~state->driver.event->deferred_events;
-		if (evs) {
-		    evoff |= evs;
-		    state->driver.event->deferred_events |= evs;
-		}
-#endif
-		active = 1;
-	    }
-	    else if (state->type != ERTS_EV_TYPE_DRV_EV) {
-		free_event = state->driver.event;
-		state->driver.event = NULL;
-	    }
-#if ERTS_CIO_DEFER_ACTIVE_EVENTS
-	    else {
-		ErtsPollEvents evs = state->events & state->driver.event->deferred_events;
-		if (evs) {
-		    evon |= evs;
-		    state->driver.event->deferred_events = 0;
-		}
-	    }
-#endif
-
-	}
-#endif
-
 #ifndef ERTS_SYS_CONTINOUS_FD_NUMBERS
 	if (((state->type != ERTS_EV_TYPE_NONE) | state->remove_cnt | active) == 0)
 	    hash_erase_drv_ev_state(state);
@@ -826,10 +716,6 @@ check_cleanup_active_fd(ErtsSysFdType fd,
 	free_drv_select_data(free_select);
     if (free_nif)
         free_nif_select_data(free_nif);
-#if ERTS_CIO_HAVE_DRV_EVENT
-    if (free_event)
-	free_drv_event_data(free_event);
-#endif
 
 #if ERTS_CIO_DEFER_ACTIVE_EVENTS
     if (evoff) {
@@ -967,9 +853,6 @@ ERTS_CIO_EXPORT(driver_select)(ErlDrvPort ix,
     ErtsDrvEventState *state;
     int wake_poller;
     int ret;
-#if ERTS_CIO_HAVE_DRV_EVENT
-    ErtsDrvEventDataState *free_event = NULL;
-#endif
     ErtsDrvSelectDataState *free_select = NULL;
     ErtsNifSelectDataState *free_nif = NULL;
 #ifdef USE_VM_PROBES
@@ -1026,9 +909,6 @@ ERTS_CIO_EXPORT(driver_select)(ErlDrvPort ix,
 #endif
 
     switch (state->type) {
-#if ERTS_CIO_HAVE_DRV_EVENT
-    case ERTS_EV_TYPE_DRV_EV:
-#endif
     case ERTS_EV_TYPE_NIF:
         drv_select_steal(ix, state, mode, on);
         break;
@@ -1168,9 +1048,6 @@ ERTS_CIO_EXPORT(driver_select)(ErlDrvPort ix,
 done:
 
     check_fd_cleanup(state,
-#if ERTS_CIO_HAVE_DRV_EVENT
-		     &free_event,
-#endif
 		     &free_select,
                      &free_nif);
 
@@ -1188,10 +1065,6 @@ done_unknown:
     if (free_nif)
         free_nif_select_data(free_nif);
 
-#if ERTS_CIO_HAVE_DRV_EVENT
-    if (free_event)
-	free_drv_event_data(free_event);
-#endif
     return ret;
 }
 
@@ -1212,9 +1085,6 @@ ERTS_CIO_EXPORT(enif_select)(ErlNifEnv* env,
     int wake_poller;
     int ret;
     enum { NO_STOP=0, CALL_STOP, CALL_STOP_AND_RELEASE } call_stop = NO_STOP;
-#if ERTS_CIO_HAVE_DRV_EVENT
-    ErtsDrvEventDataState *free_event = NULL;
-#endif
     ErtsDrvSelectDataState *free_select = NULL;
     ErtsNifSelectDataState *free_nif = NULL;
 #ifdef USE_VM_PROBES
@@ -1284,9 +1154,6 @@ ERTS_CIO_EXPORT(enif_select)(ErlNifEnv* env,
         if (state->driver.stop.resource != resource)
             nif_select_steal(state, ERL_DRV_READ | ERL_DRV_WRITE, resource, ref);
         break;
-#if ERTS_CIO_HAVE_DRV_EVENT
-    case ERTS_EV_TYPE_DRV_EV:
-#endif
     case ERTS_EV_TYPE_DRV_SEL:
         nif_select_steal(state, mode, resource, ref);
         break;
@@ -1423,9 +1290,6 @@ ERTS_CIO_EXPORT(enif_select)(ErlNifEnv* env,
 done:
 
     check_fd_cleanup(state,
-#if ERTS_CIO_HAVE_DRV_EVENT
-		     &free_event,
-#endif
 		     &free_select,
                      &free_nif);
 
@@ -1442,162 +1306,9 @@ done_unknown:
     if (free_nif)
         free_nif_select_data(free_nif);
 
-#if ERTS_CIO_HAVE_DRV_EVENT
-    if (free_event)
-	free_drv_event_data(free_event);
-#endif
     return ret;
 }
 
-
-int
-ERTS_CIO_EXPORT(driver_event)(ErlDrvPort ix,
-			      ErlDrvEvent e,
-			      ErlDrvEventData event_data)
-{
-#if !ERTS_CIO_HAVE_DRV_EVENT
-    return -1;
-#else
-    ErtsSysFdType fd = (ErtsSysFdType) e;
-    ErtsPollEvents events;
-    ErtsPollEvents add_events;
-    ErtsPollEvents remove_events;
-    Eterm id = erts_drvport2id(ix);
-    ErtsDrvEventState *state;
-    int do_wake = 0;
-    int ret;
-#if ERTS_CIO_HAVE_DRV_EVENT
-    ErtsDrvEventDataState *free_event;
-#endif
-    ErtsDrvSelectDataState *free_select;
-    ErtsNifSelectDataState *free_nif;
-    Port *prt = erts_drvport2port(ix);
-
-    if (prt == ERTS_INVALID_ERL_DRV_PORT)
-	return -1;
-
-    ERTS_LC_ASSERT(erts_lc_is_port_locked(prt));
-
-#ifdef ERTS_SYS_CONTINOUS_FD_NUMBERS
-    if ((unsigned)fd >= (unsigned)erts_atomic_read_nob(&drv_ev_state_len)) {
-	if (fd < 0)
-	    return -1;    
-	if (fd >= max_fds) {
-	    event_large_fd_error(ix, fd, event_data);
-	    return -1;
-	}
-	grow_drv_ev_state(fd);
-    }
-#endif
-
-    erts_mtx_lock(fd_mtx(fd));
-
-#ifdef ERTS_SYS_CONTINOUS_FD_NUMBERS
-    state = &drv_ev_state[(int) fd];
-#else
-    /* Could use hash_new directly, but want to keep the normal case fast */
-    state = hash_get_drv_ev_state(fd);
-    if (state == NULL) {
-	state = hash_new_drv_ev_state(fd);
-    }
-#endif
-
-    switch (state->type) {
-    case ERTS_EV_TYPE_DRV_EV:
-	if (state->driver.event->port == id) break;
-	/*fall through*/
-    case ERTS_EV_TYPE_DRV_SEL:
-	drv_event_steal(ix, state, event_data);
-	break;
-    case ERTS_EV_TYPE_STOP_USE: {
-	erts_dsprintf_buf_t *dsbufp = erts_create_logger_dsbuf();
-	print_drv_event_op(dsbufp, ix, fd, event_data);
-	steal_pending_stop_use(dsbufp, ix, state, 0, 1);
-	break;
-      }
-    }
-
-    ASSERT(state->type == ERTS_EV_TYPE_DRV_EV
-	   || state->type == ERTS_EV_TYPE_NONE);
-
-    events = state->events;
-
-    if (!event_data) {
-	remove_events = events;
-	add_events = 0;
-    }
-    else {
-	remove_events = ~event_data->events & events;
-	add_events = ~events & event_data->events;
-    }
-
-    if (add_events) {
-	events = ERTS_CIO_POLL_CTL(pollset.ps, state->fd, add_events, 1, &do_wake);
-	if (events & (ERTS_POLL_EV_ERR|ERTS_POLL_EV_NVAL)) {
-	    ret = -1;
-	    goto done;
-	}
-    }
-    if (remove_events) {
-	events = ERTS_CIO_POLL_CTL(pollset.ps, state->fd, remove_events, 0, &do_wake);
-	if (events & (ERTS_POLL_EV_ERR|ERTS_POLL_EV_NVAL)) {
-	    ret = -1;
-	    goto done;
-	}
-    }
-    if (event_data && event_data->events != 0) {
-	if (state->type == ERTS_EV_TYPE_DRV_EV) {
-	    state->driver.event->removed_events &= ~add_events;
-	    state->driver.event->removed_events |= remove_events;
-	}
-	else {
-	    if (!state->driver.event)
-		state->driver.event = alloc_drv_event_data();
-	    state->driver.event->port = id;
-	    state->driver.event->removed_events = (ErtsPollEvents) 0;
-	    state->type = ERTS_EV_TYPE_DRV_EV;
-	}
-	state->driver.event->data = event_data;
-    }
-    else {
-	if (state->type == ERTS_EV_TYPE_DRV_EV) {
-	    abort_tasks(state, 0);
-	    state->driver.event->port = NIL;
-	    state->driver.event->data = NULL;
-	    state->driver.event->removed_events = (ErtsPollEvents) 0;
-	}
-	state->type = ERTS_EV_TYPE_NONE;
-	remember_removed(state, &pollset);
-    }
-    state->events = events;
-    ASSERT(event_data ? events == event_data->events : events == 0); 
-
-    ret = 0;
-
-done:
-
-    check_fd_cleanup(state,
-#if ERTS_CIO_HAVE_DRV_EVENT
-		     &free_event,
-#endif
-		     &free_select,
-                     &free_nif);
-
-    erts_mtx_unlock(fd_mtx(fd));
-
-    if (free_select)
-	free_drv_select_data(free_select);
-    if (free_nif)
-        free_nif_select_data(free_nif);
-#if ERTS_CIO_HAVE_DRV_EVENT
-    if (free_event)
-	free_drv_event_data(free_event);
-#endif
-
-    return ret;
-#endif
-}
-
 static ERTS_INLINE int
 chk_stale(Eterm id, ErtsDrvEventState *state, int mode)
 {
@@ -1629,11 +1340,6 @@ need2steal(ErtsDrvEventState *state, int mode)
         do_steal = 1;
         break;
 
-#if ERTS_CIO_HAVE_DRV_EVENT
-    case ERTS_EV_TYPE_DRV_EV:
-	do_steal |= chk_stale(state->driver.event->port, state, 0);
-	break;
-#endif
     case ERTS_EV_TYPE_STOP_USE:
     case ERTS_EV_TYPE_STOP_NIF:
         ASSERT(0);
@@ -1716,23 +1422,6 @@ steal(erts_dsprintf_buf_t *dsbufp, ErtsDrvEventState *state, int mode)
         erts_dsprintf(dsbufp, "\n");
         break;
     }
-#if ERTS_CIO_HAVE_DRV_EVENT
-    case ERTS_EV_TYPE_DRV_EV: {
-	Eterm eid = state->driver.event->port;
-	if (is_nil(eid)) {
-	    erts_dsprintf(dsbufp, "no one", (int) state->fd);
-	    ASSERT(0);
-	}
-	else {
-	    erts_dsprintf(dsbufp, "event driver ");
-	    print_driver_name(dsbufp, eid);
-	    erts_dsprintf(dsbufp, "%T ", eid);
-	}
-	erts_dsprintf(dsbufp, "\n");
-	deselect(state, 0);
-	break;
-    }
-#endif
     case ERTS_EV_TYPE_STOP_USE:
     case ERTS_EV_TYPE_STOP_NIF: {
 	ASSERT(0);
@@ -1914,55 +1603,6 @@ steal_pending_stop_nif(erts_dsprintf_buf_t *dsbufp, ErtsResource* resource,
 
 }
 
-
-#if ERTS_CIO_HAVE_DRV_EVENT
-
-static void
-print_drv_event_op(erts_dsprintf_buf_t *dsbufp,
-                   ErlDrvPort ix, ErtsSysFdType fd, ErlDrvEventData event_data)
-{
-    Port *pp = erts_drvport2port(ix);
-    erts_dsprintf(dsbufp, "driver_event(%p, %d, ", ix, (int) fd);
-    if (!event_data)
-	erts_dsprintf(dsbufp, "NULL");
-    else
-	erts_dsprintf(dsbufp, "{0x%x, 0x%x}",
-		      (unsigned int) event_data->events,
-		      (unsigned int) event_data->revents);
-    erts_dsprintf(dsbufp, ") by ");
-    if (pp != ERTS_INVALID_ERL_DRV_PORT)
-	print_driver_name(dsbufp, pp->common.id);
-    erts_dsprintf(dsbufp, "driver %T ", pp != ERTS_INVALID_ERL_DRV_PORT ? pp->common.id : NIL);
-}
-
-static void
-drv_event_steal(ErlDrvPort ix, ErtsDrvEventState *state, ErlDrvEventData event_data)
-{
-    if (need2steal(state, ERL_DRV_READ|ERL_DRV_WRITE)) {
-	erts_dsprintf_buf_t *dsbufp = erts_create_logger_dsbuf();
-	print_drv_event_op(dsbufp, ix, state->fd, event_data);
-	steal(dsbufp, state, ERL_DRV_READ|ERL_DRV_WRITE);
-	erts_send_error_to_logger_nogl(dsbufp);
-    }
-    else if (state->type == ERTS_EV_TYPE_DRV_SEL) {
-	ASSERT(state->flags & ERTS_EV_FLAG_USED);
-	deselect(state, 0);
-    }
-}
-
-#ifdef ERTS_SYS_CONTINOUS_FD_NUMBERS
-static void
-event_large_fd_error(ErlDrvPort ix, ErtsSysFdType fd, ErlDrvEventData event_data)
-{
-    erts_dsprintf_buf_t *dsbufp = erts_create_logger_dsbuf();
-    print_drv_event_op(dsbufp, ix, fd, event_data);
-    erts_dsprintf(dsbufp, "failed: ");
-    large_fd_error_common(dsbufp, fd);
-    erts_send_error_to_logger_nogl(dsbufp);
-}
-#endif
-#endif
-
 static ERTS_INLINE int
 io_task_schedule_allowed(ErtsDrvEventState *state,
 			 ErtsPortTaskType type,
@@ -1974,30 +1614,13 @@ io_task_schedule_allowed(ErtsDrvEventState *state,
     case ERTS_PORT_TASK_INPUT:
 	if (!state->driver.select)
 	    return 0;
-#if ERTS_CIO_HAVE_DRV_EVENT
-	if (state->driver.event)
-	    return 0;
-#endif
 	io_task = &state->driver.select->iniotask;
 	break;
     case ERTS_PORT_TASK_OUTPUT:
 	if (!state->driver.select)
 	    return 0;
-#if ERTS_CIO_HAVE_DRV_EVENT
-	if (state->driver.event)
-	    return 0;
-#endif
 	io_task = &state->driver.select->outiotask;
 	break;
-#if ERTS_CIO_HAVE_DRV_EVENT
-    case ERTS_PORT_TASK_EVENT:
-	if (!state->driver.event)
-	    return 0;
-	if (state->driver.select)
-	    return 0;
-	io_task = &state->driver.event->iotask;
-	break;
-#endif
     default:
 	ERTS_INTERNAL_ERROR("Invalid I/O-task type");
 	return 0;
@@ -2090,29 +1713,6 @@ send_event_tuple(struct erts_nif_select_event* e, ErtsResource* resource,
         erts_proc_unlock(rp, rp_locks);
 }
 
-
-#if ERTS_CIO_HAVE_DRV_EVENT
-static ERTS_INLINE void
-eready(Eterm id, ErtsDrvEventState *state, ErlDrvEventData event_data,
-       erts_aint_t current_cio_time)
-{
-    if (io_task_schedule_allowed(state,
-				 ERTS_PORT_TASK_EVENT,
-				 current_cio_time)) {
-	ErtsIoTask *iotask = &state->driver.event->iotask;
-	erts_atomic_set_nob(&iotask->executed_time, current_cio_time);
-	if (erts_port_task_schedule(id,
-				    &iotask->task,
-				    ERTS_PORT_TASK_EVENT,
-				    (ErlDrvEvent) state->fd,
-				    event_data) != 0) {
-	    stale_drv_select(id, state, 0);
-	}
-	add_active_fd(state->fd);
-    }
-}
-#endif
-
 static void bad_fd_in_pollset(ErtsDrvEventState *, Eterm inport, Eterm outport);
 
 void
@@ -2338,25 +1938,6 @@ ERTS_CIO_EXPORT(erts_check_io)(int do_wait)
             goto next_pollres_unlocked;
         }
 
-#if ERTS_CIO_HAVE_DRV_EVENT
-	case ERTS_EV_TYPE_DRV_EV: { /* Requested via driver_event()... */
-	    ErlDrvEventData event_data;
-	    ErtsPollEvents revents;
-	    ASSERT(state->driver.event);
-	    ASSERT(state->driver.event->data);
-	    event_data = state->driver.event->data;
-	    revents = pollres[i].events;
-	    revents &= ~state->driver.event->removed_events;
-
-	    if (revents) {
-		event_data->events = state->events;
-		event_data->revents = revents;
-		eready(state->driver.event->port, state, event_data, current_cio_time);
-	    }
-	    break;
-	}
-#endif
-
 	case ERTS_EV_TYPE_NONE: /* Deselected ... */
 	    break;
 
@@ -2508,7 +2089,6 @@ static void drv_ev_state_free(void *des)
 struct io_functions {
     int (*select)(ErlDrvPort, ErlDrvEvent, int, int);
     int (*enif_select)(ErlNifEnv*, ErlNifEvent, enum ErlNifSelectFlags, void*, const ErlNifPid*, Eterm);
-    int (*event)(ErlDrvPort, ErlDrvEvent, ErlDrvEventData);
     void (*check_io_as_interrupt)(void);
     void (*check_io_interrupt)(int);
     void (*check_io_interrupt_tmd)(int, ErtsMonotonicTime);
@@ -2517,6 +2097,9 @@ struct io_functions {
     Uint (*size)(void);
     Eterm (*info)(void *);
     int (*check_io_debug)(ErtsCheckIoDebugInfo *);
+#ifdef ERTS_ENABLE_LOCK_COUNT
+    void (*lcnt_update_cio_locks)(int enable);
+#endif
 };
 
 # ifdef ERTS_KERNEL_POLL_VERSION
@@ -2541,7 +2124,6 @@ ERTS_CIO_EXPORT(erts_init_check_io)(void)
     ASSERT(erts_io_funcs.select == NULL);
     erts_io_funcs.select		= ERTS_CIO_EXPORT(driver_select);
     erts_io_funcs.enif_select		= ERTS_CIO_EXPORT(enif_select);
-    erts_io_funcs.event		= ERTS_CIO_EXPORT(driver_event);
     erts_io_funcs.check_io_interrupt	= ERTS_CIO_EXPORT(erts_check_io_interrupt);
     erts_io_funcs.check_io_interrupt_tmd= ERTS_CIO_EXPORT(erts_check_io_interrupt_timed);
     erts_io_funcs.check_io		= ERTS_CIO_EXPORT(erts_check_io);
@@ -2549,6 +2131,9 @@ ERTS_CIO_EXPORT(erts_init_check_io)(void)
     erts_io_funcs.size		= ERTS_CIO_EXPORT(erts_check_io_size);
     erts_io_funcs.info		= ERTS_CIO_EXPORT(erts_check_io_info);
     erts_io_funcs.check_io_debug	= ERTS_CIO_EXPORT(erts_check_io_debug);
+#ifdef ERTS_ENABLE_LOCK_COUNT
+    erts_io_funcs.lcnt_update_cio_locks	= ERTS_CIO_EXPORT(erts_lcnt_update_cio_locks);
+#endif
 #endif
 
     ERTS_CIO_POLL_INIT();
@@ -2783,7 +2368,6 @@ typedef struct {
     int used_fds;
     int num_errors;
     int no_driver_select_structs;
-    int no_driver_event_structs;
 #ifdef ERTS_SYS_CONTINOUS_FD_NUMBERS
     int internal_fds;
     ErtsPollEvents *epep;
@@ -2808,10 +2392,6 @@ static void doit_erts_check_io_debug(void *vstate, void *vcounters)
 
     if (state->driver.select)
 	counters->no_driver_select_structs++;
-#if ERTS_CIO_HAVE_DRV_EVENT
-    if (state->driver.event)
-	counters->no_driver_event_structs++;
-#endif
 
 #ifdef ERTS_SYS_CONTINOUS_FD_NUMBERS
     if (state->events || ep_events) {
@@ -2984,43 +2564,6 @@ static void doit_erts_check_io_debug(void *vstate, void *vcounters)
             r = state->driver.stop.resource;
             erts_printf(" resource=%p(%T:%T)", r, r->type->module, r->type->name);
         }
-#if ERTS_CIO_HAVE_DRV_EVENT
-	else if (state->type == ERTS_EV_TYPE_DRV_EV) {
-	    Eterm id;
-	    erts_printf("driver_event ");
-#ifdef ERTS_SYS_CONTINOUS_FD_NUMBERS
-	    if (internal) {
-		erts_printf("internal ");
-		err = 1;		    
-	    }
-	    if (cio_events == ep_events) {
-		erts_printf("ev=0x%b32x", (Uint32) cio_events);
-	    }
-	    else {
-		err = 1;
-		erts_printf("cio_ev=0x%b32x", (Uint32) cio_events);
-		erts_printf(" ep_ev=0x%b32x", (Uint32) ep_events);
-	    }
-#else
-	    erts_printf("ev=0x%b32x", (Uint32) cio_events);
-#endif
-	    id = state->driver.event->port;
-	    if (is_nil(id)) {
-		erts_printf(" port=none name=none drv=none ");
-		err = 1;
-	    }
-	    else {
-		ErtsPortNames *pnp = erts_get_port_names(id, ERTS_INVALID_ERL_DRV_PORT);
-		erts_printf(" port=%T name=%s drv=%s ",
-			    id,
-			    pnp->name ? pnp->name : "unknown",
-			    (pnp->driver_name
-			     ? pnp->driver_name
-			     : "unknown"));
-		erts_free_port_names(pnp);
-	    }
-	}
-#endif
 #ifdef ERTS_SYS_CONTINOUS_FD_NUMBERS
 	else if (internal) {
 	    erts_printf("internal ");
@@ -3071,9 +2614,6 @@ ERTS_CIO_EXPORT(erts_check_io_debug)(ErtsCheckIoDebugInfo *ciodip)
     ErtsDrvEventState null_des;
 
     null_des.driver.select = NULL;
-#if ERTS_CIO_HAVE_DRV_EVENT
-    null_des.driver.event = NULL;
-#endif
     null_des.driver.stop.drv_ptr = NULL;
     null_des.events = 0;
     null_des.remove_cnt = 0;
@@ -3096,7 +2636,6 @@ ERTS_CIO_EXPORT(erts_check_io_debug)(ErtsCheckIoDebugInfo *ciodip)
     counters.used_fds = 0;
     counters.num_errors = 0;
     counters.no_driver_select_structs = 0;
-    counters.no_driver_event_structs = 0;
 
 #ifdef ERTS_SYS_CONTINOUS_FD_NUMBERS
     len = erts_atomic_read_nob(&drv_ev_state_len);
@@ -3115,14 +2654,10 @@ ERTS_CIO_EXPORT(erts_check_io_debug)(ErtsCheckIoDebugInfo *ciodip)
 
     ciodip->no_used_fds = counters.used_fds;
     ciodip->no_driver_select_structs = counters.no_driver_select_structs;
-    ciodip->no_driver_event_structs = counters.no_driver_event_structs;
 
     erts_printf("\n");
     erts_printf("used fds=%d\n", counters.used_fds);
     erts_printf("Number of driver_select() structures=%d\n", counters.no_driver_select_structs);
-#if ERTS_CIO_HAVE_DRV_EVENT
-    erts_printf("Number of driver_event() structures=%d\n", counters.no_driver_event_structs);
-#endif
 #ifdef ERTS_SYS_CONTINOUS_FD_NUMBERS
     erts_printf("internal fds=%d\n", counters.internal_fds);
 #endif
@@ -3136,7 +2671,7 @@ ERTS_CIO_EXPORT(erts_check_io_debug)(ErtsCheckIoDebugInfo *ciodip)
 }
 
 #ifdef ERTS_ENABLE_LOCK_COUNT
-void erts_lcnt_update_cio_locks(int enable) {
+void ERTS_CIO_EXPORT(erts_lcnt_update_cio_locks)(int enable) {
 #ifndef ERTS_SYS_CONTINOUS_FD_NUMBERS
     erts_lcnt_enable_hash_lock_count(&drv_ev_state_tab, ERTS_LOCK_FLAGS_CATEGORY_IO, enable);
 #else
@@ -3167,12 +2702,6 @@ driver_select(ErlDrvPort port, ErlDrvEvent event, int mode, int on)
     return (*erts_io_funcs.select)(port, event, mode, on);
 }
 
-int
-driver_event(ErlDrvPort port, ErlDrvEvent event, ErlDrvEventData event_data)
-{
-    return (*erts_io_funcs.event)(port, event, event_data);
-}
-
 int enif_select(ErlNifEnv* env, ErlNifEvent event,
                 enum ErlNifSelectFlags flags, void* obj, const ErlNifPid* pid, Eterm ref)
 {
@@ -3217,6 +2746,13 @@ void erts_check_io_interrupt_timed(int set,
     erts_io_funcs.check_io_interrupt_tmd(set, timeout_time);
 }
 
+#ifdef ERTS_ENABLE_LOCK_COUNT
+void erts_lcnt_update_cio_locks(int enable)
+{
+    erts_io_funcs.lcnt_update_cio_locks(enable);
+}
+#endif
+
 #endif /* ERTS_KERNEL_POLL_VERSION */
 
 #endif /* !ERTS_ENABLE_KERNEL_POLL */
diff --git a/erts/emulator/sys/common/erl_check_io.h b/erts/emulator/sys/common/erl_check_io.h
index c4ab22aaff..f4d7983002 100644
--- a/erts/emulator/sys/common/erl_check_io.h
+++ b/erts/emulator/sys/common/erl_check_io.h
@@ -41,8 +41,6 @@ void erts_init_check_io(void);
 void erts_lcnt_update_cio_locks(int enable);
 #endif
 
-#endif
-
 extern erts_atomic_t erts_check_io_time;
 
 typedef struct {
@@ -85,22 +83,6 @@ erts_io_notify_port_task_executed(ErtsPortTaskHandle *pthp)
 #  define ERTS_CIO_DEFER_ACTIVE_EVENTS 0
 #endif
 
-/*
- * ErtsDrvEventDataState is used by driver_event() which is almost never
- * used. We allocate ErtsDrvEventDataState separate since we dont wan't
- * the size of ErtsDrvEventState to increase due to driver_event()
- * information.
- */
-typedef struct {
-    Eterm port;
-    ErlDrvEventData data;
-    ErtsPollEvents removed_events;
-#if ERTS_CIO_DEFER_ACTIVE_EVENTS
-    ErtsPollEvents deferred_events;
-#endif
-    ErtsIoTask iotask;
-} ErtsDrvEventDataState;
-
 typedef struct {
     Eterm inport;
     Eterm outport;
diff --git a/erts/emulator/sys/unix/sys.c b/erts/emulator/sys/unix/sys.c
index e88d7aa6df..09c515291a 100644
--- a/erts/emulator/sys/unix/sys.c
+++ b/erts/emulator/sys/unix/sys.c
@@ -510,7 +510,7 @@ break_requested(void)
       erts_exit(ERTS_INTR_EXIT, "");
 
   ERTS_SET_BREAK_REQUESTED;
-  erts_check_io_sig_interrupt();
+  erts_check_io_interrupt(1);
 }
 
 static RETSIGTYPE request_break(int signum)
diff --git a/erts/emulator/sys/win32/erl_win_dyn_driver.h b/erts/emulator/sys/win32/erl_win_dyn_driver.h
index 6f28d513c2..0d1a6d4c87 100644
--- a/erts/emulator/sys/win32/erl_win_dyn_driver.h
+++ b/erts/emulator/sys/win32/erl_win_dyn_driver.h
@@ -40,7 +40,6 @@ WDD_TYPEDEF(int, driver_exit, (ErlDrvPort, int));
 WDD_TYPEDEF(int, driver_failure_eof, (ErlDrvPort));
 WDD_TYPEDEF(void, erl_drv_busy_msgq_limits, (ErlDrvPort, ErlDrvSizeT *, ErlDrvSizeT *));
 WDD_TYPEDEF(int, driver_select, (ErlDrvPort, ErlDrvEvent, int, int));
-WDD_TYPEDEF(int, driver_event, (ErlDrvPort, ErlDrvEvent,ErlDrvEventData));
 WDD_TYPEDEF(int, driver_output, (ErlDrvPort, char *, ErlDrvSizeT));
 WDD_TYPEDEF(int, driver_output2, (ErlDrvPort, char *, ErlDrvSizeT ,char *, ErlDrvSizeT));
 WDD_TYPEDEF(int, driver_output_binary, (ErlDrvPort, char *, ErlDrvSizeT, ErlDrvBinary*, ErlDrvSizeT, ErlDrvSizeT));
@@ -162,7 +161,7 @@ typedef struct {
     WDD_FTYPE(driver_failure_eof) *driver_failure_eof;
     WDD_FTYPE(erl_drv_busy_msgq_limits) *erl_drv_busy_msgq_limits;
     WDD_FTYPE(driver_select) *driver_select;
-    WDD_FTYPE(driver_event) *driver_event;
+    void *REMOVED_driver_event;
     WDD_FTYPE(driver_output) *driver_output;
     WDD_FTYPE(driver_output2) *driver_output2;
     WDD_FTYPE(driver_output_binary) *driver_output_binary;
@@ -276,7 +275,6 @@ extern TWinDynDriverCallbacks WinDynDriverCallbacks;
 #define driver_failure_eof (WinDynDriverCallbacks.driver_failure_eof)
 #define erl_drv_busy_msgq_limits (WinDynDriverCallbacks.erl_drv_busy_msgq_limits)
 #define driver_select (WinDynDriverCallbacks.driver_select)
-#define driver_event (WinDynDriverCallbacks.driver_event)
 #define driver_output (WinDynDriverCallbacks.driver_output)
 #define driver_output2 (WinDynDriverCallbacks.driver_output2)
 #define driver_output_binary (WinDynDriverCallbacks.driver_output_binary)
@@ -414,7 +412,7 @@ do {				                        \
 ((W).driver_failure_eof) = driver_failure_eof;		\
 ((W).erl_drv_busy_msgq_limits) = erl_drv_busy_msgq_limits;\
 ((W).driver_select) = driver_select;			\
-((W).driver_event) = driver_event;			\
+((W).REMOVED_driver_event) = NULL;			\
 ((W).driver_output) = driver_output;			\
 ((W).driver_output2) = driver_output2;			\
 ((W).driver_output_binary) = driver_output_binary;	\
diff --git a/erts/emulator/test/driver_SUITE.erl b/erts/emulator/test/driver_SUITE.erl
index 5fca191679..3dffe0902c 100644
--- a/erts/emulator/test/driver_SUITE.erl
+++ b/erts/emulator/test/driver_SUITE.erl
@@ -45,7 +45,6 @@
          io_ready_exit/1,
          use_fallback_pollset/1,
          bad_fd_in_pollset/1,
-         driver_event/1,
          fd_change/1,
          steal_control/1,
          otp_6602/1,
@@ -58,11 +57,9 @@
          ioq_exit_ready_output/1,
          ioq_exit_timeout/1,
          ioq_exit_ready_async/1,
-         ioq_exit_event/1,
          ioq_exit_ready_input_async/1,
          ioq_exit_ready_output_async/1,
          ioq_exit_timeout_async/1,
-         ioq_exit_event_async/1,
          zero_extended_marker_garb_drv/1,
          invalid_extended_marker_drv/1,
          larger_major_vsn_drv/1,
@@ -139,7 +136,7 @@ suite() ->
 all() -> %% Keep a_test first and z_test last...
     [a_test, outputv_errors, outputv_echo, queue_echo, {group, timer},
      driver_unloaded, io_ready_exit, use_fallback_pollset,
-     bad_fd_in_pollset, driver_event, fd_change,
+     bad_fd_in_pollset, fd_change,
      steal_control, otp_6602, driver_system_info_base_ver,
      driver_system_info_prev_ver,
      driver_system_info_current_ver, driver_monitor,
@@ -163,9 +160,9 @@ groups() ->
        timer_change]},
      {ioq_exit, [],
       [ioq_exit_ready_input, ioq_exit_ready_output,
-       ioq_exit_timeout, ioq_exit_ready_async, ioq_exit_event,
+       ioq_exit_timeout, ioq_exit_ready_async,
        ioq_exit_ready_input_async, ioq_exit_ready_output_async,
-       ioq_exit_timeout_async, ioq_exit_event_async]}].
+       ioq_exit_timeout_async]}].
 
 init_per_suite(Config) ->
     Config.
@@ -778,7 +775,6 @@ io_ready_exit(Config) when is_list(Config) ->
 -define(CHKIO_STOP, 0).
 -define(CHKIO_USE_FALLBACK_POLLSET, 1).
 -define(CHKIO_BAD_FD_IN_POLLSET, 2).
--define(CHKIO_DRIVER_EVENT, 3).
 -define(CHKIO_FD_CHANGE, 4).
 -define(CHKIO_STEAL, 5).
 -define(CHKIO_STEAL_AUX, 6).
@@ -829,11 +825,6 @@ bad_fd_in_pollset(Config) when is_list(Config) ->
                                ?CHKIO_BAD_FD_IN_POLLSET,
                                fun () -> sleep(1000) end)).
 
-driver_event(Config) when is_list(Config) ->
-    chkio_test_fini(chkio_test(chkio_test_init(Config),
-                               ?CHKIO_DRIVER_EVENT,
-                               fun () -> sleep(1000) end)).
-
 fd_change(Config) when is_list(Config) ->
     chkio_test_fini(chkio_test(chkio_test_init(Config),
                                ?CHKIO_FD_CHANGE,
@@ -1336,11 +1327,9 @@ driver_monitor(Config) when is_list(Config) ->
 -define(IOQ_EXIT_READY_OUTPUT, 2).
 -define(IOQ_EXIT_TIMEOUT, 3).
 -define(IOQ_EXIT_READY_ASYNC, 4).
--define(IOQ_EXIT_EVENT, 5).
 -define(IOQ_EXIT_READY_INPUT_ASYNC, 6).
 -define(IOQ_EXIT_READY_OUTPUT_ASYNC, 7).
 -define(IOQ_EXIT_TIMEOUT_ASYNC, 8).
--define(IOQ_EXIT_EVENT_ASYNC, 9).
 
 ioq_exit_test(Config, TestNo) ->
     Drv = ioq_exit_drv,
@@ -1393,9 +1382,6 @@ ioq_exit_timeout(Config) when is_list(Config) ->
 ioq_exit_ready_async(Config) when is_list(Config) ->
     ioq_exit_test(Config, ?IOQ_EXIT_READY_ASYNC).
 
-ioq_exit_event(Config) when is_list(Config) ->
-    ioq_exit_test(Config, ?IOQ_EXIT_EVENT).
-
 ioq_exit_ready_input_async(Config) when is_list(Config) ->
     ioq_exit_test(Config, ?IOQ_EXIT_READY_INPUT_ASYNC).
 
@@ -1405,9 +1391,6 @@ ioq_exit_ready_output_async(Config) when is_list(Config) ->
 ioq_exit_timeout_async(Config) when is_list(Config) ->
     ioq_exit_test(Config, ?IOQ_EXIT_TIMEOUT_ASYNC).
 
-ioq_exit_event_async(Config) when is_list(Config) ->
-    ioq_exit_test(Config, ?IOQ_EXIT_EVENT_ASYNC).
-
 
 vsn_mismatch_test(Config, LoadResult) ->
     Path = proplists:get_value(data_dir, Config),
@@ -2275,7 +2258,7 @@ z_test(Config) when is_list(Config) ->
 
 check_io_debug() ->
     get_stable_check_io_info(),
-    {NoErrorFds, NoUsedFds, NoDrvSelStructs, NoDrvEvStructs} = CheckIoDebug
+    {NoErrorFds, NoUsedFds, NoDrvSelStructs} = CheckIoDebug
     = erts_debug:get_internal_state(check_io_debug),
     HasGetHost = has_gethost(),
     ct:log("check_io_debug: ~p~n"
@@ -2289,7 +2272,6 @@ check_io_debug() ->
             %% one extra used fd that is not selected on
             ok
     end,
-    0 = NoDrvEvStructs,
     ok.
 
 has_gethost() ->
diff --git a/erts/emulator/test/driver_SUITE_data/chkio_drv.c b/erts/emulator/test/driver_SUITE_data/chkio_drv.c
index 8e5e81665c..aed6752033 100644
--- a/erts/emulator/test/driver_SUITE_data/chkio_drv.c
+++ b/erts/emulator/test/driver_SUITE_data/chkio_drv.c
@@ -42,7 +42,6 @@
 #define CHKIO_STOP				0
 #define CHKIO_USE_FALLBACK_POLLSET		1
 #define CHKIO_BAD_FD_IN_POLLSET			2
-#define CHKIO_DRIVER_EVENT			3
 #define CHKIO_FD_CHANGE				4
 #define CHKIO_STEAL				5
 #define CHKIO_STEAL_AUX				6
@@ -67,15 +66,6 @@ typedef struct {
 } ChkioFallbackData;
 
 typedef struct {
-    int in_fd;
-    struct erl_drv_event_data in_data;
-    int in_ok;
-    int out_fd;
-    struct erl_drv_event_data out_data;
-    int out_ok;
-} ChkioDriverEvent;
-
-typedef struct {
     int fds[2];
     int same_fd;
 } ChkioFdChange;
@@ -86,14 +76,10 @@ typedef struct {
 
 typedef struct {
     int driver_select_fds[2];
-    int driver_event_fds[2];
-    struct erl_drv_event_data event_data[2];
 } ChkioSteal;
 
 typedef struct {
     int driver_select_fds[2];
-    int driver_event_fds[2];
-    struct erl_drv_event_data event_data[2];
 } ChkioStealAux;
 
 
@@ -141,7 +127,6 @@ static ErlDrvData chkio_drv_start(ErlDrvPort, char *);
 static void chkio_drv_stop(ErlDrvData);
 static void chkio_drv_ready_input(ErlDrvData, ErlDrvEvent);
 static void chkio_drv_ready_output(ErlDrvData, ErlDrvEvent);
-static void chkio_drv_ready_event(ErlDrvData, ErlDrvEvent, ErlDrvEventData);
 static ErlDrvSSizeT chkio_drv_control(ErlDrvData, unsigned int,
 				      char *, ErlDrvSizeT, char **, ErlDrvSizeT);
 static void chkio_drv_timeout(ErlDrvData);
@@ -164,7 +149,7 @@ static ErlDrvEntry chkio_drv_entry = {
     NULL, /* ready_async */
     NULL, /* flush */
     NULL, /* call */
-    chkio_drv_ready_event,
+    NULL, /* unused_event_callback */
 
     ERL_DRV_EXTENDED_MARKER,
     ERL_DRV_EXTENDED_MAJOR_VERSION,
@@ -243,25 +228,6 @@ stop_use_fallback_pollset(ChkioDrvData *cddp)
 }
 
 static void
-stop_driver_event(ChkioDrvData *cddp)
-{
-    if (cddp->test_data) {
-	ChkioDriverEvent *cdep = cddp->test_data;
-	cddp->test_data = NULL;
-
-	if (cdep->in_fd >= 0) {
-	    driver_event(cddp->port, (ErlDrvEvent) (ErlDrvSInt) cdep->in_fd, NULL);
-	    close(cdep->in_fd);
-	}
-	if (cdep->out_fd >= 0) {
-	    driver_event(cddp->port, (ErlDrvEvent) (ErlDrvSInt) cdep->out_fd, NULL);
-	    close(cdep->out_fd);
-	}
-	driver_free(cdep);	    
-    }
-}
-
-static void
 stop_fd_change(ChkioDrvData *cddp)
 {
     if (cddp->test_data) {
@@ -305,14 +271,6 @@ stop_steal(ChkioDrvData *cddp)
 			  (ErlDrvEvent) (ErlDrvSInt) csp->driver_select_fds[1],
 			  DO_WRITE,
 			  0);
-	if (csp->driver_event_fds[0] >= 0)
-	    driver_event(cddp->port,
-			 (ErlDrvEvent) (ErlDrvSInt) csp->driver_event_fds[0],
-			 NULL);
-	if (csp->driver_event_fds[1] >= 0)
-	    driver_event(cddp->port,
-			 (ErlDrvEvent) (ErlDrvSInt) csp->driver_event_fds[1],
-			 NULL);
 	driver_free(csp);
     }
 }
@@ -327,10 +285,6 @@ stop_steal_aux(ChkioDrvData *cddp)
 	    close(csap->driver_select_fds[0]);
 	if (csap->driver_select_fds[1] >= 0)
 	    close(csap->driver_select_fds[1]);
-	if (csap->driver_event_fds[0] >= 0)
-	    close(csap->driver_event_fds[0]);
-	if (csap->driver_event_fds[1] >= 0)
-	    close(csap->driver_event_fds[1]);
 	driver_free(csap);
     }
 }
@@ -445,9 +399,6 @@ chkio_drv_stop(ErlDrvData drv_data) {
     case CHKIO_BAD_FD_IN_POLLSET:
 	stop_bad_fd_in_pollset(cddp);
 	break;
-    case CHKIO_DRIVER_EVENT:
-	stop_driver_event(cddp);
-	break;
     case CHKIO_FD_CHANGE:
 	stop_fd_change(cddp);
 	break;
@@ -621,55 +572,6 @@ chkio_drv_ready_input(ErlDrvData drv_data, ErlDrvEvent event)
 }
 
 static void
-chkio_drv_ready_event(ErlDrvData drv_data,
-		      ErlDrvEvent event,
-		      ErlDrvEventData event_data)
-{
-#ifdef UNIX
-    ChkioDrvData *cddp = (ChkioDrvData *) drv_data;
-    switch (cddp->test) {
-    case CHKIO_DRIVER_EVENT: {
-#ifdef HAVE_POLL_H
-	ChkioDriverEvent *cdep = cddp->test_data;
-	int fd = (int) (ErlDrvSInt) event;
-	if (fd == cdep->in_fd) {
-	    if (event_data->events == POLLIN
-		&& event_data->revents == POLLIN) {
-		cdep->in_ok++;
-	    }
-	    else {
-		driver_failure_atom(cddp->port, "invalid_input_fd_events");
-	    }
-	    break;
-	}
-	if (fd == cdep->out_fd) {
-	    if (event_data->events == POLLOUT
-		&& event_data->revents == POLLOUT) {
-		cdep->out_ok++;
-	    }
-	    else {
-		driver_failure_atom(cddp->port, "invalid_output_fd_events");
-	    }
-	    break;
-	}
-#endif
-    }
-    case CHKIO_STEAL:
-#ifdef HAVE_POLL_H
-	break;
-#endif
-    case CHKIO_STEAL_AUX:
-#ifdef HAVE_POLL_H
-	break;
-#endif
-    default:
-	driver_failure_atom(cddp->port, "unexpected_ready_event");
-	break;
-    }
-#endif /* UNIX */
-}
-
-static void
 chkio_drv_timeout(ErlDrvData drv_data)
 {
 #ifdef UNIX
@@ -779,25 +681,6 @@ chkio_drv_control(ErlDrvData drv_data,
 	    res_len = -1;
 	    stop_bad_fd_in_pollset(cddp);
 	    break;
-	case CHKIO_DRIVER_EVENT: {
-	    ChkioDriverEvent *cdep = cddp->test_data;
-	    if (!cdep->in_ok || !cdep->out_ok) {
-		if (!cdep->in_ok)
-		    driver_failure_atom(cddp->port, "got_no_input_events");
-		if (!cdep->out_ok)
-		    driver_failure_atom(cddp->port, "got_no_output_events");
-	    }
-	    else {
-		char *c = driver_alloc(sizeof(char)*2*30);
-		if (!c)
-		    driver_failure_posix(cddp->port, ENOMEM);
-		*rbuf = c;
-		res_len = sprintf(c, "in=%d\nout=%d\n",
-				  cdep->in_ok, cdep->out_ok);
-	    }
-	    stop_driver_event(cddp);
-	    break;
-	}
 	case CHKIO_FD_CHANGE: {
 	    ChkioFdChange *cfcp = cddp->test_data;
 	    if (!cfcp->same_fd)
@@ -937,69 +820,6 @@ chkio_drv_control(ErlDrvData drv_data,
 	res_len = -1;
 	break;
     }
-    case CHKIO_DRIVER_EVENT: {
-#ifndef HAVE_POLL_H
-	res_str = "skip: Need the poll.h header for this test, but it doesn't exist";
-	res_len = -1;
-#else /* HAVE_POLL_H */
-	int in_fd = open("/dev/zero", O_RDONLY);
-	int out_fd = open("/dev/null", O_WRONLY);
-
-	if (in_fd < 0 || out_fd < 0) {
-	    if (in_fd >= 0)
-		close(in_fd);
-	    if (out_fd >= 0)
-		close(out_fd);
-	    driver_failure_posix(cddp->port, errno);
-	}
-	else {
-	    ChkioDriverEvent *cdep = driver_alloc(sizeof(ChkioDriverEvent));
-	    if (!cdep)
-		driver_failure_posix(cddp->port, ENOMEM);
-	    else {
-		int res;
-		cddp->test_data = cdep;
-
-		cdep->in_fd = in_fd;
-		cdep->in_data.events = POLLIN;
-		cdep->in_data.revents = 0;
-		cdep->in_ok = 0;
-
-		res = driver_event(cddp->port,
-				   (ErlDrvEvent) (ErlDrvSInt) in_fd,
-				   &cdep->in_data);
-		if (res < 0) {
-		    res_str = "skip: driver_event() not supported";
-		    res_len = -1;
-		    close(in_fd);
-		    close(out_fd);
-		    cdep->in_fd = -1;
-		    cdep->out_fd = -1;
-		}
-		else {
-		    res_str = "ok";
-		    res_len = -1;
-
-		    cdep->out_fd = out_fd;
-		    cdep->out_data.events = POLLOUT;
-		    cdep->out_data.revents = 0;
-		    cdep->out_ok = 0;
-
-		    res = driver_event(cddp->port,
-				       (ErlDrvEvent) (ErlDrvSInt) out_fd,
-				       &cdep->out_data);
-		    if (res < 0) {
-			close(out_fd);
-			cdep->out_fd = -1;
-			driver_failure_atom(cddp->port, "driver_event_failed");
-		    }
-		}
-
-	    }
-	}
-#endif /* HAVE_POLL_H */
-	break;
-    }
     case CHKIO_FD_CHANGE: {
 	ChkioFdChange *cfcp = driver_alloc(sizeof(ChkioFdChange));
 	if (!cfcp)
@@ -1028,58 +848,19 @@ chkio_drv_control(ErlDrvData drv_data,
 	    res_len = -1;
 	}
 	else {
-	    int driver_event_fds[2];
 	    int driver_select_fds[2];
 	    cddp->test_data = csp; 
 	    memcpy(c, buf, len);
 	    c[len] = '\0';
 	    if (sscanf(c,
-		       "fds:%d:%d:%d:%d",
+		       "fds:%d:%d",
 		       &driver_select_fds[0],
-		       &driver_select_fds[1],
-		       &driver_event_fds[0],
-		       &driver_event_fds[1]) != 4)
-		driver_failure_atom(cddp->port, "bad_input");
+		       &driver_select_fds[1]) != 2)
+                driver_failure_atom(cddp->port, "bad_input");
 	    else {
 		int res = 0;
-		if (driver_event_fds[0] < 0) { /* Have no working driver_event() ... */
-		    csp->driver_select_fds[0] = driver_select_fds[0]; /* In */
-		    csp->driver_select_fds[1] = driver_select_fds[1]; /* Out */
-		    csp->driver_event_fds[0] = -1;
-		    csp->driver_event_fds[1] = -1;
-		}
-		else { /* Have working driver_event() ... */
-#ifndef HAVE_POLL_H
-		    driver_failure_atom(cddp->port, "unexpected_result");
-		    res = -1;
-#else
-		    csp->driver_select_fds[0] = driver_select_fds[0]; /* In */
-		    csp->driver_event_fds[1] = driver_select_fds[1]; /* Out */
-		    csp->driver_event_fds[0] = driver_event_fds[0]; /* In */
-		    csp->driver_select_fds[1] = driver_event_fds[1]; /* Out */
-
-		    /* Steal with driver_event() */
-
-		    csp->event_data[0].events = POLLIN;
-		    csp->event_data[0].revents = 0;
-		    res = driver_event(cddp->port,
-				       (ErlDrvEvent) (ErlDrvSInt) csp->driver_event_fds[0],
-				       &csp->event_data[0]);
-		    if (res < 0)
-			driver_failure_atom(cddp->port,
-					    "driver_event_failed_to_steal");
-		    if (res >= 0) {
-			csp->event_data[1].events = POLLOUT;
-			csp->event_data[1].revents = 0;
-			res = driver_event(cddp->port,
-					   (ErlDrvEvent) (ErlDrvSInt) csp->driver_event_fds[1],
-					   &csp->event_data[1]);
-			if (res < 0)
-			    driver_failure_atom(cddp->port,
-						"driver_event_failed_to_steal");
-		    }
-#endif
-		}
+                csp->driver_select_fds[0] = driver_select_fds[0]; /* In */
+                csp->driver_select_fds[1] = driver_select_fds[1]; /* Out */
 
 		/* Steal with driver_select() */
 		if (res >= 0) {
@@ -1109,37 +890,17 @@ chkio_drv_control(ErlDrvData drv_data,
 	break;
     }
     case CHKIO_STEAL_AUX: {
-	int read_fds[2];
-	int write_fds[2];
-
-	read_fds[0] = open("/dev/zero", O_RDONLY);
-	write_fds[0] = open("/dev/null", O_WRONLY);
+	int read_fd;
+	int write_fd;
 
-#ifdef HAVE_POLL_H
-	read_fds[1] = open("/dev/zero", O_RDONLY);
-	write_fds[1] = open("/dev/null", O_WRONLY);
-#else
-	read_fds[1] = -1;
-	write_fds[1] = -1;
-#endif
+	read_fd = open("/dev/zero", O_RDONLY);
+	write_fd = open("/dev/null", O_WRONLY);
 	
-	if (read_fds[0] < 0
-	    || write_fds[0] < 0
-#ifdef HAVE_POLL_H
-	    || read_fds[1] < 0 
-	    || write_fds[1] < 0
-#endif
-	    ) {
-	    if (read_fds[0] < 0)
-		close(read_fds[0]);
-	    if (write_fds[0] < 0)
-		close(write_fds[0]);
-#ifdef HAVE_POLL_H
-	    if (read_fds[1] < 0)
-		close(read_fds[1]);
-	    if (write_fds[1] < 0)
-		close(write_fds[1]);
-#endif
+	if (read_fd < 0 || write_fd < 0) {
+	    if (read_fd < 0)
+		close(read_fd);
+	    if (write_fd < 0)
+		close(write_fd);
 	    driver_failure_posix(cddp->port, errno);
 	}
 	else {
@@ -1153,11 +914,8 @@ chkio_drv_control(ErlDrvData drv_data,
 		int res;
 		cddp->test_data = csap;
 
-		csap->driver_select_fds[0] = read_fds[0];
-		csap->driver_select_fds[1] = write_fds[0];
-
-		csap->driver_event_fds[0] = read_fds[1];
-		csap->driver_event_fds[1] = write_fds[1];
+		csap->driver_select_fds[0] = read_fd;
+		csap->driver_select_fds[1] = write_fd;
 
 		res = driver_select(cddp->port,
 				    (ErlDrvEvent) (ErlDrvSInt) csap->driver_select_fds[0],
@@ -1173,32 +931,6 @@ chkio_drv_control(ErlDrvData drv_data,
 		    if (res < 0)
 			driver_failure_atom(cddp->port, "driver_select_failed");
 		}
-#ifdef HAVE_POLL_H
-		if (res >= 0) {
-		    csap->event_data[0].events = POLLIN;
-		    csap->event_data[0].revents = 0;
-		    res = driver_event(cddp->port,
-				       (ErlDrvEvent) (ErlDrvSInt) csap->driver_event_fds[0],
-				       &csap->event_data[0]);
-		    if (res < 0) {
-			close(csap->driver_event_fds[0]);
-			csap->driver_event_fds[0] = -1;
-			close(csap->driver_event_fds[1]);
-			csap->driver_event_fds[1] = -1;
-			res = 0;
-		    }
-		    else {
-			csap->event_data[1].events = POLLOUT;
-			csap->event_data[1].revents = 0;
-			res = driver_event(cddp->port,
-					   (ErlDrvEvent) (ErlDrvSInt) csap->driver_event_fds[1],
-					   &csap->event_data[1]);
-			if (res < 0)
-			    driver_failure_atom(cddp->port,
-						"driver_event_failed");
-		    }
-		}
-#endif
 		if (res < 0) {
 		    res_str = "error";
 		    res_len = -1;
@@ -1213,11 +945,9 @@ chkio_drv_control(ErlDrvData drv_data,
 		    else {
 			*rbuf = c;
 			res_len = sprintf(c,
-					  "fds:%d:%d:%d:%d",
+					  "fds:%d:%d",
 					  csap->driver_select_fds[0],
-					  csap->driver_select_fds[1],
-					  csap->driver_event_fds[0],
-					  csap->driver_event_fds[1]);
+					  csap->driver_select_fds[1]);
 		    }
 		}
 	    }
diff --git a/erts/emulator/test/driver_SUITE_data/ioq_exit_drv.c b/erts/emulator/test/driver_SUITE_data/ioq_exit_drv.c
index d87c2bec93..fa58e9d5ec 100644
--- a/erts/emulator/test/driver_SUITE_data/ioq_exit_drv.c
+++ b/erts/emulator/test/driver_SUITE_data/ioq_exit_drv.c
@@ -25,8 +25,7 @@
  *		- ready_input(),
  *		- ready_output(),
  *		- timeout(),
- *		- driver_async() -> read_async(), and
- *		- event()
+ *		- driver_async() -> read_async()
  */
 
 #ifndef UNIX
@@ -65,11 +64,9 @@ typedef enum {
     IOQ_EXIT_READY_OUTPUT = 2,
     IOQ_EXIT_TIMEOUT = 3,
     IOQ_EXIT_READY_ASYNC = 4,
-    IOQ_EXIT_EVENT = 5,
     IOQ_EXIT_READY_INPUT_ASYNC = 6,
     IOQ_EXIT_READY_OUTPUT_ASYNC = 7,
     IOQ_EXIT_TIMEOUT_ASYNC = 8,
-    IOQ_EXIT_EVENT_ASYNC = 9
 } IOQExitTest;
 
 typedef struct {
@@ -80,9 +77,6 @@ typedef struct {
     int outstanding_async_task;
     long async_task;
     ErlDrvPDL pdl;
-#ifdef HAVE_POLL_H
-    struct erl_drv_event_data event_data;
-#endif
 } IOQExitDrvData;
 
 #define EV2FD(EV) ((int) ((long) (EV)))
@@ -97,8 +91,6 @@ static ErlDrvSSizeT control(ErlDrvData, unsigned int,
 static void timeout(ErlDrvData drv_data);
 static void ready_async(ErlDrvData drv_data, ErlDrvThreadData thread_data);
 static void flush(ErlDrvData drv_data);
-static void event(ErlDrvData drv_data, ErlDrvEvent event,
-		  ErlDrvEventData event_data);
 static void async_invoke(void*);
 static void do_driver_async(IOQExitDrvData *);
 
@@ -118,7 +110,7 @@ static ErlDrvEntry ioq_exit_drv_entry = {
     ready_async,
     flush,
     NULL /* call */,
-    event,
+    NULL /* unused_event_callback*/,
     ERL_DRV_EXTENDED_MARKER,
     ERL_DRV_EXTENDED_MAJOR_VERSION,
     ERL_DRV_EXTENDED_MINOR_VERSION,
@@ -149,10 +141,6 @@ start(ErlDrvPort port, char *command)
     ddp->outstanding_async_task = 0;
     ddp->async_task = -1;
     ddp->pdl = driver_pdl_create(port);
-#ifdef HAVE_POLL_H
-    ddp->event_data.events = (short) 0;
-    ddp->event_data.revents = (short) 0;
-#endif
 
     return (ErlDrvData) ddp;
 }
@@ -192,27 +180,6 @@ static ErlDrvSSizeT control(ErlDrvData drv_data,
 #else
 	goto done;
 #endif
-    case IOQ_EXIT_EVENT:
-    case IOQ_EXIT_EVENT_ASYNC:
-#ifdef UNIX
-#ifdef HAVE_POLL_H
-	ddp->ofd = open("/dev/null", O_WRONLY);
-	if (ddp->ofd < 0) {
-	    driver_failure_posix(ddp->port, errno);
-	    return 0;
-	}
-	else if (driver_event(ddp->port, FD2EV(ddp->ofd), NULL) != 0) {
-	    res_str = "skip: driver_event() not supported";
-	    goto done;
-	}
-#else
-	res_str = "skip: No poll.h found which is needed for this test";
-	goto done;
-#endif
-	break;
-#else /* UNIX */
-	goto done;
-#endif
     case IOQ_EXIT_TIMEOUT:
     case IOQ_EXIT_TIMEOUT_ASYNC:
 	break;
@@ -266,13 +233,6 @@ static void stop(ErlDrvData drv_data)
 		close(ddp->ofd);
 	    }
 	    break;
-	case IOQ_EXIT_EVENT:
-	case IOQ_EXIT_EVENT_ASYNC:
-	    if (ddp->ofd >= 0) {
-		driver_event(ddp->port, FD2EV(ddp->ofd), NULL);
-		close(ddp->ofd);
-	    }
-	    break;
 #endif
 	case IOQ_EXIT_TIMEOUT:
 	case IOQ_EXIT_TIMEOUT_ASYNC:
@@ -302,13 +262,6 @@ static void flush(ErlDrvData drv_data)
     case IOQ_EXIT_READY_OUTPUT_ASYNC:
 	driver_select(ddp->port, FD2EV(ddp->ofd), DO_WRITE, 1);
 	break;
-    case IOQ_EXIT_EVENT:
-    case IOQ_EXIT_EVENT_ASYNC:
-#ifdef HAVE_POLL_H
-	ddp->event_data.events |= POLLOUT;
-	driver_event(ddp->port, FD2EV(ddp->ofd), &ddp->event_data);
-#endif
-	break;
 #endif
     case IOQ_EXIT_TIMEOUT:
     case IOQ_EXIT_TIMEOUT_ASYNC:
@@ -395,30 +348,6 @@ static void ready_async(ErlDrvData drv_data, ErlDrvThreadData thread_data)
     }
 }
 
-static void event(ErlDrvData drv_data,
-		  ErlDrvEvent event,
-		  ErlDrvEventData event_data)
-{
-    IOQExitDrvData *ddp = (IOQExitDrvData *) drv_data;
-
-    PRINTF(("event(%p, %d, %p) called\r\n", drv_data, EV2FD(event), event_data));
-
-#if defined(UNIX) && defined(HAVE_POLL_H)
-    if (ddp->ofd == EV2FD(event)) {
-	driver_event(ddp->port, FD2EV(ddp->ofd), NULL);
-	close(ddp->ofd);
-	ddp->ofd = -1;
-	if (ddp->test == IOQ_EXIT_EVENT_ASYNC)
-	    do_driver_async(ddp);
-	else {
-	    driver_pdl_lock(ddp->pdl);
-	    driver_deq(ddp->port, 1);
-	    driver_pdl_unlock(ddp->pdl);
-	}
-    }
-#endif
-}
-
 static void async_invoke(void *arg)
 {
     PRINTF(("async_invoke(%p) called\r\n", arg));
diff --git a/erts/emulator/test/driver_SUITE_data/missing_callback_drv.c b/erts/emulator/test/driver_SUITE_data/missing_callback_drv.c
index e7480d2e00..14838f0377 100644
--- a/erts/emulator/test/driver_SUITE_data/missing_callback_drv.c
+++ b/erts/emulator/test/driver_SUITE_data/missing_callback_drv.c
@@ -41,10 +41,6 @@
 typedef struct {
     int ofd;
     int ifd;
-    int efd;
-#ifdef HAVE_POLL_H
-    struct erl_drv_event_data edata;
-#endif
 } mcd_data_t;
 
 static ErlDrvData start(ErlDrvPort port, char *command);
@@ -90,7 +86,6 @@ start(ErlDrvPort port, char *command)
 
     mcd->ofd = -1;
     mcd->ifd = -1;
-    mcd->efd = -1;
 
 #ifdef UNIX
 
@@ -105,15 +100,6 @@ start(ErlDrvPort port, char *command)
 	goto error;
     if (driver_select(port, (ErlDrvEvent) (long) mcd->ifd, DO_READ, 1) != 0)
 	goto error;
-
-#ifdef HAVE_POLL_H
-    mcd->efd = open("/dev/null", O_WRONLY);
-    if (mcd->efd < 0)
-	goto error;
-    mcd->edata.events = POLLOUT;
-    mcd->edata.revents = 0;
-    driver_event(port, (ErlDrvEvent) (long) mcd->efd, &mcd->edata);
-#endif
 #endif
 
     driver_set_timer(port, 0);
@@ -135,10 +121,6 @@ stop(ErlDrvData data)
 	    close(mcd->ofd);
 	if (mcd->ifd >= 0)
 	    close(mcd->ifd);
-#ifdef HAVE_POLL_H
-	if (mcd->efd >= 0)
-	    close(mcd->efd);
-#endif
 #endif
 	driver_free(mcd);
     }
diff --git a/erts/emulator/test/lttng_SUITE.erl b/erts/emulator/test/lttng_SUITE.erl
index a012fa1da2..19c3844c40 100644
--- a/erts/emulator/test/lttng_SUITE.erl
+++ b/erts/emulator/test/lttng_SUITE.erl
@@ -81,7 +81,6 @@ end_per_testcase(Case, _Config) ->
 
 %% Not tested yet
 %%   org_erlang_otp:driver_process_exit
-%%   org_erlang_otp:driver_event
 
 %% tracepoints
 %%
@@ -100,7 +99,6 @@ end_per_testcase(Case, _Config) ->
 %%   org_erlang_otp:driver_flush
 %%   org_erlang_otp:driver_stop_select
 %%   org_erlang_otp:driver_timeout
-%%   org_erlang_otp:driver_event
 %%   org_erlang_otp:driver_ready_output
 %%   org_erlang_otp:driver_ready_input
 %%   org_erlang_otp:driver_output
@@ -431,7 +429,6 @@ txt() ->
       "%%   org_erlang_otp:driver_flush\n"
       "%%   org_erlang_otp:driver_stop_select\n"
       "%%   org_erlang_otp:driver_timeout\n"
-      "%%   org_erlang_otp:driver_event\n"
       "%%   org_erlang_otp:driver_ready_output\n"
       "%%   org_erlang_otp:driver_ready_input\n"
       "%%   org_erlang_otp:driver_output\n"
diff --git a/system/doc/tutorial/port_driver.c b/system/doc/tutorial/port_driver.c
index 37de67310f..8b441733ed 100644
--- a/system/doc/tutorial/port_driver.c
+++ b/system/doc/tutorial/port_driver.c
@@ -51,8 +51,7 @@ ErlDrvEntry example_driver_entry = {
 				   queue */
     NULL,                       /* F_PTR call, much like control, sync call
 				   to driver */
-    NULL,                       /* F_PTR event, called when an event selected 
-				   by driver_event() occurs. */
+    NULL,                       /* unused */
     ERL_DRV_EXTENDED_MARKER,    /* int extended marker, Should always be 
 				   set to indicate driver versioning */
     ERL_DRV_EXTENDED_MAJOR_VERSION, /* int major_version, should always be