Reset RT Handle size every now and then in editor if set to a big resolution and then reverted back

com.unity.render-pipelines.core/Runtime/Textures/RTHandleSystem.cs

@@ -67,6 +67,10 @@ internal enum ResizeMode
 
         int m_MaxWidths = 0;
         int m_MaxHeights = 0;
+#if UNITY_EDITOR
+        // In editor every now and then we must reset the size of the rthandle system if it was set very high and then switched back to a much smaller scale. 
+        int m_FramesSinceLastReset = 0;
+#endif
 
         /// <summary>
         /// RTHandleSystem constructor.
@@ -172,6 +176,22 @@ public void SetReferenceSize(int width, int height, MSAASamples msaaSamples, boo
             width = Mathf.Max(width, 1);
             height = Mathf.Max(height, 1);
 
+#if UNITY_EDITOR
+            // If the reference size is significantly higher than the current actualWidth/Height and it is larger than 1440p dimensions, we reset the reference size every several frames
+            // in editor to avoid issues if a large resolution was temporarily set.
+            const int resetInterval = 100;
+            if (((m_MaxWidths / (float)width) > 2.0f && m_MaxWidths > 2560) ||
+                ((m_MaxHeights / (float)height) > 2.0f && m_MaxHeights > 1440))
+            {
+                if (m_FramesSinceLastReset > resetInterval)
+                {
+                    m_FramesSinceLastReset = 0;
+                    ResetReferenceSize(width, height);
+                }
+                m_FramesSinceLastReset++;
+            }
+#endif
+
             bool sizeChanged = width > GetMaxWidth() || height > GetMaxHeight() || reset;
             bool msaaSamplesChanged = (msaaSamples != m_ScaledRTCurrentMSAASamples);
 

com.unity.render-pipelines.high-definition/CHANGELOG.md

@@ -26,6 +26,7 @@ The version number for this package has increased due to a version update of a r
 - Fixed precision issue with the atmospheric fog.
 - Fixed issue with TAA and no motion vectors.
 - Fixed the stripping not working the terrain alphatest feature required for terrain holes (case 1205902).
+- Fix an issue that caused issues of usability of editor if a very high resolution is set by mistake and then reverted back to a smaller resolution.
 
 ### Changed
 - Combined occlusion meshes into one to reduce draw calls and state changes with XR single-pass.