On X11, fix WaitUntil and Poll behavior

Co-authored-by: Kirill Chibisov <contact@kchibisov.com>

CHANGELOG.md

@@ -24,6 +24,7 @@ And please only add new entries to the top of this list, right below the `# Unre
 - **Breaking:** Moved `ControlFlow::Exit` to `EventLoopWindowTarget::exit()` and `EventLoopWindowTarget::exiting()` and removed `ControlFlow::ExitWithCode(_)` entirely.
 - On Web, add `EventLoopWindowTargetExtWebSys` and `PollStrategy`, which allows to set different strategies for `ControlFlow::Poll`. By default the Prioritized Task Scheduling API is used, but an option to use `Window.requestIdleCallback` is available as well. Both use `setTimeout()`, with a trick to circumvent throttling to 4ms, as a fallback.
 - Implement `PartialOrd` and `Ord` for `MouseButton`.
+- On X11, fix event loop not waking up on `ControlFlow::Poll` and `ControlFlow::WaitUntil`.
 
 # 0.29.1-beta
 

src/platform_impl/linux/x11/mod.rs

@@ -505,18 +505,6 @@ impl<T: 'static> EventLoop<T> {
             return;
         }
 
-        // False positive / spurious wake ups could lead to us spamming
-        // redundant iterations of the event loop with no new events to
-        // dispatch.
-        //
-        // If there's no readable event source then we just double check if we
-        // have any pending `_receiver` events and if not we return without
-        // running a loop iteration.
-        // If we don't have any pending `_receiver`
-        if !self.has_pending() && !self.state.x11_readiness.readable {
-            return;
-        }
-
         // NB: `StartCause::Init` is handled as a special case and doesn't need
         // to be considered here
         let cause = match self.control_flow() {
@@ -540,6 +528,23 @@ impl<T: 'static> EventLoop<T> {
             }
         };
 
+        // False positive / spurious wake ups could lead to us spamming
+        // redundant iterations of the event loop with no new events to
+        // dispatch.
+        //
+        // If there's no readable event source then we just double check if we
+        // have any pending `_receiver` events and if not we return without
+        // running a loop iteration.
+        // If we don't have any pending `_receiver`
+        if !self.has_pending()
+            && !matches!(
+                &cause,
+                StartCause::ResumeTimeReached { .. } | StartCause::Poll
+            )
+        {
+            return;
+        }
+
         self.single_iteration(&mut callback, cause);
     }