diff --git a/src/xcb_conn.c b/src/xcb_conn.c
index 7979491..8be1849 100644
--- a/src/xcb_conn.c
+++ b/src/xcb_conn.c
@@ -286,6 +286,7 @@ xcb_connection_t *xcb_connect_to_fd(int fd, xcb_auth_info_t *auth_info)
     if(!(
         set_fd_flags(fd) &&
         pthread_mutex_init(&c->iolock, 0) == 0 &&
+        pthread_mutex_init(&c->pllock, 0) == 0 &&
         _xcb_in_init(&c->in) &&
         _xcb_out_init(&c->out) &&
         write_setup(c, auth_info) &&
@@ -313,6 +314,7 @@ void xcb_disconnect(xcb_connection_t *c)
     close(c->fd);
 
     pthread_mutex_destroy(&c->iolock);
+    pthread_mutex_destroy(&c->pllock);
     _xcb_in_destroy(&c->in);
     _xcb_out_destroy(&c->out);
 
@@ -405,18 +407,21 @@ int _xcb_conn_wait(xcb_connection_t *c, pthread_cond_t *cond, struct iovec **vec
 
     pthread_mutex_unlock(&c->iolock);
     do {
+        pthread_mutex_lock(&c->pllock);
 #if USE_POLL
         ret = poll(&fd, 1, -1);
         /* If poll() returns an event we didn't expect, such as POLLNVAL, treat
          * it as if it failed. */
         if(ret >= 0 && (fd.revents & ~fd.events))
         {
+            pthread_mutex_unlock(&c->pllock);
             ret = -1;
             break;
         }
 #else
         ret = select(c->fd + 1, &rfds, &wfds, 0, 0);
 #endif
+        pthread_mutex_unlock(&c->pllock);
     } while (ret == -1 && errno == EINTR);
     if(ret < 0)
     {
diff --git a/src/xcbint.h b/src/xcbint.h
index f9e5a52..55fb296 100644
--- a/src/xcbint.h
+++ b/src/xcbint.h
@@ -183,6 +183,7 @@ struct xcb_connection_t {
 
     /* I/O data */
     pthread_mutex_t iolock;
+    pthread_mutex_t pllock;
     _xcb_in in;
     _xcb_out out;