diff --git a/frontend/device/input.lua b/frontend/device/input.lua
index 215f2d32e..0a8ae532e 100644
--- a/frontend/device/input.lua
+++ b/frontend/device/input.lua
@@ -473,21 +473,20 @@ end
 
 -- main event handling:
 
-function Input:waitEvent(timeout_us, timeout_s)
+function Input:waitEvent(timeout_us)
     -- wrapper for input.waitForEvents that will retry for some cases
     local ok, ev
-    local wait_deadline = TimeVal:now() + TimeVal:new{
-            sec = timeout_s,
-            usec = timeout_us
-        }
     while true do
         if #self.timer_callbacks > 0 then
+            local wait_deadline = TimeVal:now() + TimeVal:new{
+                usec = timeout_us
+            }
             -- we don't block if there is any timer, set wait to 10us
             while #self.timer_callbacks > 0 do
                 ok, ev = pcall(input.waitForEvent, 100)
                 if ok then break end
                 local tv_now = TimeVal:now()
-                if ((not timeout_us and not timeout_s) or tv_now < wait_deadline) then
+                if (not timeout_us or tv_now < wait_deadline) then
                     -- check whether timer is up
                     if tv_now >= self.timer_callbacks[1].deadline then
                         local touch_ges = self.timer_callbacks[1].callback()
diff --git a/frontend/ui/uimanager.lua b/frontend/ui/uimanager.lua
index 6e0e2bf97..e46590720 100644
--- a/frontend/ui/uimanager.lua
+++ b/frontend/ui/uimanager.lua
@@ -637,13 +637,10 @@ function UIManager:handleInput()
         end
     elseif wait_until[1] > now[1]
     or wait_until[1] == now[1] and wait_until[2] > now[2] then
-        local wait_for = { s = wait_until[1] - now[1], us = wait_until[2] - now[2] }
-        if wait_for.us < 0 then
-            wait_for.s = wait_for.s - 1
-            wait_for.us = MILLION + wait_for.us
-        end
         -- wait until next task is pending
-        input_event = Input:waitEvent(wait_for.us, wait_for.s)
+        local wait_us = (wait_until[1] - now[1]) * MILLION
+                        + (wait_until[2] - now[2])
+        input_event = Input:waitEvent(wait_us)
     end
 
     -- delegate input_event to handler