diff --git a/helpers.h b/helpers.h
index 6535624..cd19c8a 100644
--- a/helpers.h
+++ b/helpers.h
@@ -1,13 +1,34 @@
 #ifndef HELPERS_SENTRY
 #define HELPERS_SENTRY
 
-#define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0]))
-
 #define KB(n) (((unsigned long long)(n)) << 10)
 #define MB(n) (((unsigned long long)(n)) << 20)
 #define GB(n) (((unsigned long long)(n)) << 30)
 #define TB(n) (((unsigned long long)(n)) << 40)
 
+#define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0]))
+
+#define MIN(a,b) (((a)<(b))?(a):(b))
+#define MAX(a,b) (((a)>(b))?(a):(b))
+
 #define SWAP(T, a, b) do { T t__ = a; a = b; b = t__; } while(0)
 
+#define PI      3.1415926535897f
+#define EPSILON 4.94065645841247e-324
+
+#define MAX_U64 (unsigned long long)0xffffffffffffffffull
+#define MAX_U32       (unsigned int)0xffffffff
+#define MAX_U16     (unsigned short)0xffff
+#define MAX_U8       (unsigned char)0xff
+
+#define MAX_S64   (long long)0x7fffffffffffffffll
+#define MAX_S32         (int)0x7fffffff
+#define MAX_S16       (short)0x7fff
+#define MAX_S8  (signed char)0x7f
+
+#define MIN_S64   (long long)0x8000000000000000ll
+#define MIN_S32         (int)0x80000000
+#define MIN_S16       (short)0x8000
+#define MIN_S8  (signed char)0x80
+
 #endif
diff --git a/slock.c b/slock.c
index b15eb55..3b443dd 100644
--- a/slock.c
+++ b/slock.c
@@ -745,7 +745,7 @@ run_loop(struct arena *arena,
     struct timeval tv;
     KeySym ksym;
     XEvent ev;
-    unsigned long long rendering_timeout_millis;
+    unsigned long long rendering_timeout_millis, failure_timeout_millis;
     struct dpms_state dpms_state;
     struct fonts fonts;
     int kbl_brightness;
@@ -775,6 +775,7 @@ run_loop(struct arena *arena,
     needs_rendering = 1;
 
     rendering_timeout_millis = millis();
+    failure_timeout_millis = 0;
 
     while(running) {
         fd_set fds;
@@ -851,44 +852,47 @@ run_loop(struct arena *arena,
 #endif
                 }
 
-                switch (ksym) {
-                case XK_Return:
-                    passwd[len] = '\0';
-                    errno = 0;
-                    if (!(inputhash = crypt(passwd, hash)))
-                        fprintf(stderr, "slock: crypt: %s\n", strerror(errno));
-                    else
-                        running = !!strcmp(inputhash, hash);
-                    if (running) {
-                        XBell(dpy, 100);
-                        failure = 1;
-                    } else {
-                        locked = 0;
-                    }
-                    explicit_bzero(&passwd, sizeof(passwd));
-                    len = 0;
-                    break;
-                case XK_Escape:
-                    explicit_bzero(&passwd, sizeof(passwd));
-                    len = 0;
-                    failure = 0;
-                    break;
-                case XK_BackSpace:
-                    if (len)
-                        passwd[--len] = '\0';
-                    break;
-                default:
-                    if (num && !iscntrl((unsigned char)buf[0]) &&
-                        (len + num < sizeof(passwd))) {
-                        memcpy(passwd + len, buf, num);
-                        len += num;
-                    } else if (buf[0] == '\025') { /* ctrl-u clears input */
+                if(millis() - failure_timeout_millis >= 2000) {
+                    switch (ksym) {
+                    case XK_Return:
+                        passwd[len] = '\0';
+                        errno = 0;
+                        if (!(inputhash = crypt(passwd, hash)))
+                            fprintf(stderr, "slock: crypt: %s\n", strerror(errno));
+                        else
+                            running = !!strcmp(inputhash, hash);
+                        if (running) {
+                            XBell(dpy, 100);
+                            failure = 1;
+                            failure_timeout_millis = millis();
+                        } else {
+                            locked = 0;
+                        }
                         explicit_bzero(&passwd, sizeof(passwd));
                         len = 0;
-                    } else {
-                        continue; /* Don't trigger fail screen when pressing control characters */
+                        break;
+                    case XK_Escape:
+                        explicit_bzero(&passwd, sizeof(passwd));
+                        len = 0;
+                        failure = 0;
+                        break;
+                    case XK_BackSpace:
+                        if (len)
+                            passwd[--len] = '\0';
+                        break;
+                    default:
+                        if (num && !iscntrl((unsigned char)buf[0]) &&
+                            (len + num < sizeof(passwd))) {
+                            memcpy(passwd + len, buf, num);
+                            len += num;
+                        } else if (buf[0] == '\025') { /* ctrl-u clears input */
+                            explicit_bzero(&passwd, sizeof(passwd));
+                            len = 0;
+                        } else {
+                            continue; /* Don't trigger fail screen when pressing control characters */
+                        }
+                        break;
                     }
-                    break;
                 }
             } else if (rr->active && ev.type == rr->evbase + RRScreenChangeNotify) {
                 rre = (XRRScreenChangeNotifyEvent*)&ev;