diff --git a/src/adb/xdbd_adb.c b/src/adb/xdbd_adb.c
index 096a0a8..2b530e6 100644
--- a/src/adb/xdbd_adb.c
+++ b/src/adb/xdbd_adb.c
@@ -43,7 +43,7 @@ size_t xdbd_adb_read_adb_header(xdbd_adb_request_t *r) {
     }
 
     if (n == 0) {
-        bfdev_log_debug("close connection by client\n");
+        bfdev_log_debug("%s close connection by client\n", __func__);
     }
 
     if (n == 0 || n == XDBD_ERR) {
@@ -102,7 +102,7 @@ size_t xdbd_adb_read_adb_payload(xdbd_adb_request_t *r) {
     }
 
     if (n == 0) {
-        bfdev_log_debug("close connection by client\n");
+        bfdev_log_debug("%s close connection by client\n", __func__);
     }
 
     if (n == 0 || n == XDBD_ERR) {
@@ -247,7 +247,7 @@ void xdbd_adb_process_adb_header(xdbd_event_t *rev) {
 void xdbd_adb_wait_apacket_handler(xdbd_event_t *ev) {
     bfdev_log_debug("xdbd_adb_wait_apacket_handler\n");
     xdbd_connection_t *c;
-    size_t n;
+    ssize_t n;
     xdbd_buf_t *b;
     size_t size;
     c = ev->data;
@@ -287,7 +287,7 @@ void xdbd_adb_wait_apacket_handler(xdbd_event_t *ev) {
     }
 
     if (n == 0) {
-        bfdev_log_debug("close connection by client\n");
+        bfdev_log_debug("%s close connection by client, %d\n", __func__, c->read_fd);
         xdbd_adb_close_connection(c);
         return;
     }
diff --git a/src/connection/connection.c b/src/connection/connection.c
index 5579b05..70b39d5 100644
--- a/src/connection/connection.c
+++ b/src/connection/connection.c
@@ -12,7 +12,7 @@ FIXME: remove this
 #include <fcntl.h>
 #include <unistd.h>
 
-xdbd_connection_t *xdbd_get_connection(xdbd_t *xdbd, xdbd_socket_t s) {
+xdbd_connection_t *xdbd_get_connection(xdbd_t *xdbd, xdbd_socket_t read, xdbd_socket_t write) {
     xdbd_connection_t *c;
     xdbd_event_t *rev, *wev;
 
@@ -23,7 +23,9 @@ xdbd_connection_t *xdbd_get_connection(xdbd_t *xdbd, xdbd_socket_t s) {
         return NULL;
     }
 
-    bfdev_log_err("xdbd_get_connection get c->fd %d, c %p\n", s, c);
+    bfdev_log_err("xdbd_get_connection get c->read_fd %d, c %p\n", read, c);
+    bfdev_log_err("xdbd_get_connection get c->write_fd %d, c %p\n", write, c);
+
     xdbd->free_connections = c->data;
     xdbd->free_connection_n--;
 
@@ -34,7 +36,8 @@ xdbd_connection_t *xdbd_get_connection(xdbd_t *xdbd, xdbd_socket_t s) {
 
     c->read = rev;
     c->write = wev;
-    c->fd = s;
+    c->read_fd = read;
+    c->write_fd = write;
 
     xdbd_memzero(rev, sizeof(xdbd_event_t));
     xdbd_memzero(wev, sizeof(xdbd_event_t));
@@ -55,10 +58,50 @@ void xdbd_free_connection(xdbd_t *xdbd, xdbd_connection_t *c) {
     xdbd->free_connection_n++;
 }
 
+
+void xdbd_connection_fd_free(xdbd_connection_t *c)
+{
+    xdbd_socket_t read_fd, write_fd;
+    xdbd_err_t err;
+
+    read_fd = c->read_fd;
+    c->read_fd = (xdbd_socket_t) -1;
+
+    write_fd = c->write_fd;
+    c->write_fd = (xdbd_socket_t) -1;
+
+    bfdev_log_err("xdbd_close_connection close c->read_fd %d, c %p\n", c->read_fd, c);
+    bfdev_log_err("xdbd_close_connection close c->write_fd %d, c %p\n", c->write_fd, c);
+
+    if (read_fd == write_fd) {
+        if (xdbd_close(read_fd) == -1) {
+            err = xdbd_socket_errno;
+            bfdev_log_debug("xdbd_close read_fd error");
+        }
+
+        return;
+    }
+
+    //read_fd != write_fd
+    if (xdbd_close(read_fd) == -1) {
+        err = xdbd_socket_errno;
+        bfdev_log_debug("xdbd_close read_fd error");
+    }
+
+    if (xdbd_close(write_fd) == -1) {
+        err = xdbd_socket_errno;
+        bfdev_log_debug("xdbd_close write_fd error");
+    }
+
+}
+
 void xdbd_close_connection(xdbd_t *xdbd, xdbd_connection_t *c) {
-    xdbd_socket_t fd;
+    xdbd_socket_t read_fd, write_fd;
     xdbd_err_t err;
-    if (c->fd == (xdbd_socket_t) -1) {
+    if (c->read_fd == (xdbd_socket_t) -1) {
+        return;
+    }
+    if (c->write_fd == (xdbd_socket_t) -1) {
         return;
     }
 
@@ -73,18 +116,8 @@ void xdbd_close_connection(xdbd_t *xdbd, xdbd_connection_t *c) {
     c->read->closed = 1;
     c->write->closed = 1;
 
-    bfdev_log_err("xdbd_close_connection close c->fd %d, c %p\n", c->fd, c);
-
-    xdbd_free_connection(xdbd, c);
-
-    fd = c->fd;
-    c->fd = (xdbd_socket_t) -1;
-
-    if (xdbd_close(fd) == -1) {
-        err = xdbd_socket_errno;
-
-        bfdev_log_debug("xdbd_close error");
-    }
+    xdbd_free_connection(c->listening->xdbd, c);
+    xdbd_connection_fd_free(c);
 }
 
 ssize_t xdbd_unix_recv(xdbd_connection_t *c, u_char *buf, size_t size) {
@@ -94,7 +127,7 @@ ssize_t xdbd_unix_recv(xdbd_connection_t *c, u_char *buf, size_t size) {
 
     rev = c->read;
     do {
-        n = recv(c->fd, buf, size, 0);
+        n = recv(c->read_fd, buf, size, 0);
 
         // bfdev_log_debug("recv: fd:%d %z of %uz", c->fd, n, size);
 
@@ -146,7 +179,7 @@ ssize_t xdbd_unix_read(xdbd_connection_t *c, u_char *buf, size_t size) {
 
     rev = c->read;
     do {
-        n = read(c->fd, buf, size);
+        n = read(c->read_fd, buf, size);
 
         // bfdev_log_debug("recv: fd:%d %z of %uz", c->fd, n, size);
 
@@ -199,7 +232,7 @@ ssize_t xdbd_unix_send(xdbd_connection_t *c, u_char *buf, size_t size) {
     wev = c->write;
 
     for ( ;; ) {
-        n = send(c->fd, buf, size, 0);
+        n = send(c->write_fd, buf, size, 0);
 
         // bfdev_log_debug("send: fd:%d %z of %uz", c->fd, n, size);
 
@@ -246,7 +279,7 @@ ssize_t xdbd_unix_write(xdbd_connection_t *c, u_char *buf, size_t size) {
     wev = c->write;
 
     for ( ;; ) {
-        n = write(c->fd, buf, size);
+        n = write(c->write_fd, buf, size);
 
         // bfdev_log_debug("send: fd:%d %z of %uz", c->fd, n, size);
 
diff --git a/src/connection/connection.h b/src/connection/connection.h
index 88272ca..de31458 100644
--- a/src/connection/connection.h
+++ b/src/connection/connection.h
@@ -8,7 +8,8 @@
 struct xdbd_connection_s {
     xdbd_pool_t *pool;
     xdbd_pool_t *temp_pool;
-    xdbd_socket_t fd;
+    xdbd_socket_t read_fd;
+    xdbd_socket_t write_fd;
     xdbd_event_t *read;
     xdbd_event_t *write;
 
@@ -41,8 +42,9 @@ struct xdbd_peer_connection_s {
 
 #define ADB_CONNECTION_DEFAULT_PORT 5555
 
-xdbd_connection_t *xdbd_get_connection(xdbd_t *xdbd, xdbd_socket_t s);
+xdbd_connection_t *xdbd_get_connection(xdbd_t *xdbd, xdbd_socket_t read, xdbd_socket_t write);
 void xdbd_free_connection(xdbd_t *xdbd, xdbd_connection_t *c);
+void xdbd_connection_fd_free(xdbd_connection_t *c);
 void xdbd_close_connection(xdbd_t *xdbd, xdbd_connection_t *c);
 
 ssize_t xdbd_unix_recv(xdbd_connection_t *c, u_char *buf, size_t size);
diff --git a/src/connection/usb/xdbd_connection_usb.c b/src/connection/usb/xdbd_connection_usb.c
index 4cf0481..feb3e52 100644
--- a/src/connection/usb/xdbd_connection_usb.c
+++ b/src/connection/usb/xdbd_connection_usb.c
@@ -217,36 +217,53 @@ FIXME: make this request async
 
 void xdbd_event_usb_accept(xdbd_event_t *ev) {
 	xdbd_usb_listening_t *uls;
-	xdbd_connection_t *c;
+	xdbd_connection_t *lc, *c;
+	xdbd_event_t       *rev, *wev;
 #if defined(XDBD_CONFIG_OSX)
 	bfdev_log_err("OSX not support yet\r\n");
 	return;
 #endif
 
-	c = ev->data;
-	uls = c->ulistening;
+	lc = ev->data;
+	uls = lc->ulistening;
 
 	if (xdbd_event_open_usb_connection(uls) != XDBD_OK) {
 		return;
 	}
 
-	uls->conn_ctl = xdbd_get_connection(c->ulistening->xdbd, uls->fd_ctr);
+	uls->conn_ctl = xdbd_get_connection(lc->ulistening->xdbd, uls->fd_ctr, uls->fd_ctr);
 	if (uls->conn_ctl == NULL) {
 		return;
 	}
 
-	uls->conn_in = xdbd_get_connection(c->ulistening->xdbd, uls->fd_in);
-	if (uls->conn_ctl == NULL) {
+	c = xdbd_get_connection(lc->ulistening->xdbd, uls->fd_out, uls->fd_in);
+	if (c == NULL) {
 		return;
 	}
 
-	uls->conn_out = xdbd_get_connection(c->ulistening->xdbd, uls->fd_out);
-	if (uls->conn_ctl == NULL) {
-		return;
-	}
+	c = uls->conn_data;
+
+
+	c->pool = xdbd_create_pool();
+    if (c->pool == NULL) {
+        return;
+    }
+
+    c->temp_pool = xdbd_create_pool();
+    if (c->temp_pool == NULL) {
+        return;
+    }
 
-	//FIXME: how to process ctl, in and out???
+	c->send = xdbd_unix_send;
+    c->recv = xdbd_unix_recv;
 
+	wev = c->write;
+	rev = c->read;
+
+	wev->ready = 1;
+
+	uls->handler(c);
 
 	ev->accepted = 1;
+	return;
 }
diff --git a/src/connection/usb/xdbd_connection_usb.h b/src/connection/usb/xdbd_connection_usb.h
index e1eba8d..054e2dd 100644
--- a/src/connection/usb/xdbd_connection_usb.h
+++ b/src/connection/usb/xdbd_connection_usb.h
@@ -20,8 +20,7 @@ struct xdbd_usb_listening_s {
 
     //process connection
     xdbd_connection_t *conn_ctl;
-    xdbd_connection_t *conn_in;
-    xdbd_connection_t *conn_out;
+    xdbd_connection_t *conn_data;
 
     xdbd_socket_t fd_ctr;
     xdbd_socket_t fd_in;
diff --git a/src/event/select/xdbd_select.c b/src/event/select/xdbd_select.c
index e3e9548..1c7283b 100644
--- a/src/event/select/xdbd_select.c
+++ b/src/event/select/xdbd_select.c
@@ -74,17 +74,23 @@ static int xdbd_select_add_event(xdbd_event_t *ev, int event, unsigned flags) {
         return XDBD_OK;
     }
 
-    bfdev_log_debug("select add event c->fd %d\n", c->fd);
+
     if (event == XDBD_READ_EVENT) {
-        FD_SET(c->fd, &master_read_fd_set);
+        bfdev_log_debug("select add read event c->read_fd %d\n", c->read_fd);
+        FD_SET(c->read_fd, &master_read_fd_set);
     }
 
     if (event == XDBD_WRITE_EVENT) {
-        FD_SET(c->fd, &master_write_fd_set);
+        bfdev_log_debug("select add write event c->write_fd %d\n", c->write_fd);
+        FD_SET(c->write_fd, &master_write_fd_set);
+    }
+
+    if (max_fd != -1 && max_fd < c->read_fd) {
+        max_fd = c->read_fd;
     }
 
-    if (max_fd != -1 && max_fd < c->fd) {
-        max_fd = c->fd;
+    if (max_fd != -1 && max_fd < c->write_fd) {
+        max_fd = c->write_fd;
     }
 
     ev->active = 1;
@@ -105,16 +111,21 @@ static int xdbd_select_del_event(xdbd_event_t *ev, int event, unsigned flags) {
         return XDBD_ERR;
     }
 
-    bfdev_log_debug("select delete event c->fd %d\n", c->fd);
     if (event == XDBD_READ_EVENT) {
-        FD_CLR(c->fd, &master_read_fd_set);
+        bfdev_log_debug("select delete event c->read_fd %d\n", c->read_fd);
+        FD_CLR(c->read_fd, &master_read_fd_set);
     }
 
     if (event == XDBD_WRITE_EVENT) {
-        FD_CLR(c->fd, &master_write_fd_set);
+        bfdev_log_debug("select delete event c->write_fd %d\n", c->write_fd);
+        FD_CLR(c->write_fd, &master_write_fd_set);
     }
 
-    if (c->fd == max_fd) {
+    if (c->read_fd == max_fd) {
+        max_fd = -1;
+    }
+
+    if (c->write_fd == max_fd) {
         max_fd = -1;
     }
 
@@ -184,8 +195,11 @@ static int xdbd_select_process_events(xdbd_t *xdbd, xdbd_msec_t timer, unsigned
     if (max_fd == -1) {
         for (i = 0; i < nevents; i++) {
             c = event_index[i]->data;
-            if (max_fd < c->fd) {
-                max_fd = c->fd;
+            if (max_fd < c->read_fd) {
+                max_fd = c->read_fd;
+            }
+            if (max_fd < c->write_fd) {
+                max_fd = c->write_fd;
             }
         }
 
@@ -248,14 +262,14 @@ static int xdbd_select_process_events(xdbd_t *xdbd, xdbd_msec_t timer, unsigned
         found = 0;
 
         if (ev->write) {
-            if (FD_ISSET(c->fd, &work_write_fd_set)) {
+            if (FD_ISSET(c->write_fd, &work_write_fd_set)) {
                 found = 1;
             }
         }
 
         /*read event*/
         if (!ev->write) {
-            if (FD_ISSET(c->fd, &work_read_fd_set)) {
+            if (FD_ISSET(c->read_fd, &work_read_fd_set)) {
                 found = 1;
             }
         }
diff --git a/src/event/xdbd_event.c b/src/event/xdbd_event.c
index dcc718e..2563946 100644
--- a/src/event/xdbd_event.c
+++ b/src/event/xdbd_event.c
@@ -87,16 +87,10 @@ int xdbd_handle_write_event(xdbd_event_t *wev, unsigned flags) {
 
 static void
 xdbd_close_accepted_connection(xdbd_connection_t *c) {
-    xdbd_socket_t s;
+    xdbd_socket_t read_fd, write_fd;
 
     xdbd_free_connection(c->listening->xdbd, c);
-
-    s = c->fd;
-    c->fd = (xdbd_socket_t)-1;
-
-    if (xdbd_close(s) == (xdbd_socket_t) -1) {
-        bfdev_log_err("xdbd_close close error");
-    }
+    xdbd_connection_fd_free(c);
 
     if (c->pool) {
         xdbd_destroy_pool(c->pool);
@@ -136,13 +130,13 @@ static void xdbd_event_accept(xdbd_event_t *ev) {
 
     socklen = sizeof(xdbd_sockaddr_t);
 
-    s = accept(lc->fd,  &sa.sockaddr, &socklen);
+    s = accept(lc->read_fd, &sa.sockaddr, &socklen);
     if (s == (xdbd_socket_t) -1) {
         //FIXME: add some check
         return;
     }
 
-    c = xdbd_get_connection(ls->xdbd, s);
+    c = xdbd_get_connection(ls->xdbd, s, s);
     if (c == NULL) {
         return;
     }
@@ -360,7 +354,8 @@ static int xdbd_event_init_connections(xdbd_t *xdbd) {
         c[i].data = next;
         c[i].read = &xdbd->read_events[i];
         c[i].write = &xdbd->write_events[i];
-        c[i].fd = (xdbd_socket_t) -1;
+        c[i].read_fd = (xdbd_socket_t) -1;
+        c[i].write_fd = (xdbd_socket_t) -1;
         next = &c[i];
     }
 
@@ -371,7 +366,7 @@ static int xdbd_event_init_connections(xdbd_t *xdbd) {
     assert(ls != NULL);
 
     for (i = 0; i < bfdev_array_index(&xdbd->tcp_listening); i++) {
-        c = xdbd_get_connection(xdbd, ls[i].fd);
+        c = xdbd_get_connection(xdbd, ls[i].fd, ls[i].fd);
         if (c == NULL) {
             return XDBD_ERR;
         }
@@ -394,7 +389,8 @@ static int xdbd_event_init_connections(xdbd_t *xdbd) {
     assert(uls != NULL);
 
     for (i = 0; i < bfdev_array_index(&xdbd->usb_listening); i++) {
-        c = xdbd_get_connection(xdbd, XDBD_CONNECTION_USB_TIMER_FD);
+        c = xdbd_get_connection(xdbd, XDBD_CONNECTION_USB_TIMER_FD, XDBD_CONNECTION_USB_TIMER_FD);
+
         if (c == NULL) {
             return XDBD_ERR;
         }
diff --git a/src/service/shell/xdbd_shell_service.c b/src/service/shell/xdbd_shell_service.c
index f8c866d..c348581 100644
--- a/src/service/shell/xdbd_shell_service.c
+++ b/src/service/shell/xdbd_shell_service.c
@@ -121,7 +121,7 @@ static void xdbd_event_shell_handler(xdbd_event_t *ev) {
 xdbd_connection_t *create_service_connection(xdbd_t *xdbd, xdbd_adb_request_t *r, xdbd_shell_service_t *ss) {
     xdbd_connection_t *c;
     xdbd_event_t *rev;
-    c = xdbd_get_connection(xdbd, ss->fd);
+    c = xdbd_get_connection(xdbd, ss->fd, ss->fd);
 
     if (c == NULL) {
         return NULL;