AutoSuspend: Make sure we send a LeaveStandby event ASAP (#9173)

Even in corner cases where we're woken up without user input (e.g., rtc alarm).

(Followup to #9124)

frontend/apps/reader/modules/readercoptlistener.lua

@@ -145,12 +145,10 @@ function ReaderCoptListener:onResume()
     end
 
     self:headerRefresh()
-    self:rescheduleHeaderRefreshIfNeeded()
 end
 
 function ReaderCoptListener:onLeaveStandby()
     self:headerRefresh()
-    self:rescheduleHeaderRefreshIfNeeded()
 end
 
 function ReaderCoptListener:onOutOfScreenSaver()
@@ -160,7 +158,6 @@ function ReaderCoptListener:onOutOfScreenSaver()
 
     self._delayed_screensaver = nil
     self:headerRefresh()
-    self:rescheduleHeaderRefreshIfNeeded()
 end
 
 -- Unschedule on these events

frontend/apps/reader/modules/readerfooter.lua

@@ -766,8 +766,9 @@ end
 
 function ReaderFooter:unscheduleFooterAutoRefresh()
     if not self.autoRefreshFooter then return end -- not yet set up
+    -- Slightly different wording than in rescheduleFooterAutoRefreshIfNeeded because it might not actually be scheduled at all
+    logger.dbg("ReaderFooter: unschedule autoRefreshFooter")
     UIManager:unschedule(self.autoRefreshFooter)
-    logger.dbg("ReaderFooter.autoRefreshFooter unscheduled")
 end
 
 function ReaderFooter:rescheduleFooterAutoRefreshIfNeeded()
@@ -808,12 +809,12 @@ function ReaderFooter:rescheduleFooterAutoRefreshIfNeeded()
     if schedule then
         UIManager:scheduleIn(61 - tonumber(os.date("%S")), self.autoRefreshFooter)
         if not unscheduled then
-            logger.dbg("ReaderFooter.autoRefreshFooter scheduled")
+            logger.dbg("ReaderFooter: scheduled autoRefreshFooter")
         else
-            logger.dbg("ReaderFooter.autoRefreshFooter rescheduled")
+            logger.dbg("ReaderFooter: rescheduled autoRefreshFooter")
         end
     elseif unscheduled then
-        logger.dbg("ReaderFooter.autoRefreshFooter unscheduled")
+        logger.dbg("ReaderFooter: unscheduled autoRefreshFooter")
     end
 end
 

frontend/ui/uimanager.lua

@@ -1659,6 +1659,12 @@ function UIManager:handleInput()
     -- this function emits (plugin), or within waitEvent() right after (hardware).
     -- Anywhere else breaks preventStandby/allowStandby invariants used by background jobs while UI is left running.
     self:_standbyTransition()
+    if self.PM_INPUT_TIMEOUT then
+        -- If the PM state transition requires an early return from input polling, honor that.
+        -- c.f., UIManager:setPMInputTimeout (and AutoSuspend:AllowStandbyHandler).
+        deadline = now + time.s(self.PM_INPUT_TIMEOUT)
+        self.PM_INPUT_TIMEOUT = nil
+    end
 
     -- wait for next batch of events
     local input_events = Input:waitEvent(now, deadline)
@@ -1841,6 +1847,12 @@ function UIManager:_standbyTransition()
     self._prev_prevent_standby_count = self._prevent_standby_count
 end
 
+-- Used by a PM transition event handler to request an early return from input polling (value in s).
+-- NOTE: We can't re-use setInputTimeout to avoid interactions with ZMQ...
+function UIManager:setPMInputTimeout(timeout)
+    self.PM_INPUT_TIMEOUT = timeout
+end
+
 --- Broadcasts a `FlushSettings` Event to *all* widgets.
 function UIManager:flushSettings()
     self:broadcastEvent(Event:new("FlushSettings"))

plugins/autosuspend.koplugin/main.lua

@@ -204,12 +204,6 @@ function AutoSuspend:_unschedule_standby()
     end
 
     -- Make sure we don't trigger a ghost LeaveStandby event...
-    if self.wrapped_leave_standby_task then
-        logger.dbg("AutoSuspend: unschedule leave standby task wrapper")
-        UIManager:unschedule(self.wrapped_leave_standby_task)
-        self.wrapped_leave_standby_task = nil
-    end
-
     if self.leave_standby_task then
         logger.dbg("AutoSuspend: unschedule leave standby task")
         UIManager:unschedule(self.leave_standby_task)
@@ -338,8 +332,6 @@ end
 
 function AutoSuspend:onLeaveStandby()
     logger.dbg("AutoSuspend: onLeaveStandby")
-    -- If the Event got through, tickAfterNext did its thing, clear the reference to the initial nextTick wrapper...
-    self.wrapped_leave_standby_task = nil
     -- Unschedule suspend and shutdown, as the realtime clock has ticked
     self:_unschedule()
     -- Reschedule suspend and shutdown (we'll recompute the delay based on the last user input, *not* the current time).
@@ -599,8 +591,21 @@ function AutoSuspend:AllowStandbyHandler()
         -- to make sure UIManager will consume the input events that woke us up first
         -- (in case we were woken up by user input, as opposed to an rtc wake alarm)!
         -- (This ensures we'll use an up to date last_action_time, and that it only ever gets updated from *user* input).
-        -- NOTE: UIManager consumes scheduled tasks before input events, which is why we can't use nextTick.
-        self.wrapped_leave_standby_task = UIManager:tickAfterNext(self.leave_standby_task)
+        -- NOTE: While UIManager consumes scheduled tasks before input events, we do *NOT* have to rely on tickAfterNext,
+        --       solely because of where we run inside an UI frame (via UIManager:_standbyTransition):
+        --       we're neither a scheduled task nor an input event, we run *between* scheduled tasks and input polling.
+        --       That means we go straight to input polling when returning, *without* a trip through the task queue
+        --       (c.f., UIManager:_checkTasks in UIManager:handleInput).
+        UIManager:nextTick(self.leave_standby_task)
+
+        -- Since we go straight to input polling, and that our time spent in standby won't have affected the already computed
+        -- input polling deadline (because MONOTONIC doesn't tick during standby/suspend),
+        -- tweak said deadline to make sure poll will return immediately, so we get a chance to run through the task queue ASAP.
+        -- This ensures we get a LeaveStandby event in a timely fashion,
+        -- even when there isn't actually any user input happening (e.g., woken up by the rtc alarm).
+        -- This shouldn't prevent us from actually consuming any pending input events first,
+        -- because if we were woken up by user input, those events should already be in the evdev queue...
+        UIManager:setPMInputTimeout(0)
     end
 end