diff --git a/README.md b/README.md
index f619660..b1c39eb 100644
--- a/README.md
+++ b/README.md
@@ -69,7 +69,7 @@ CHECK STORAGE
 
 ### 4. DisplayController、OLED 与 RGB
 
-每个当前故障都是 DisplayController 中的一个 active request，包含稳定 ID、priority、severity、OLED 显示数据、首次发现时间、最后变化时间和元数据。监控只提交或清除 request。DisplayController 始终只选一个 owner，OLED 和 RGB 同步表达该 owner；`NORMAL_HOME` 是 priority 0 的常驻 request，有任何故障 owner 时不会抢回显示权。同优先级新 request 排队而不抢占，owner 恢复后按 priority、first_seen、ID 重新仲裁。历史 power flags 只进入 diagnose 和一次性 Journal 记录。
+每个当前故障都是 DisplayController 中的一个 active request，包含稳定 ID、priority、severity、OLED 显示数据、首次发现时间、最后变化时间和元数据。监控只提交或清除 request，同一轮采样作为一个原子批次，全部更新后只仲裁一次。DisplayController 始终只选一个 owner，OLED 和 RGB 同步表达该 owner；`NORMAL_HOME` 是 priority 0 的常驻 request，有任何故障 owner 时不会抢回显示权。同优先级新 request 排队而不抢占，owner 恢复后按 priority、first_seen、ID 重新仲裁。历史 power flags 只进入 diagnose 和一次性 Journal 记录。
 
 ### 5. RGB 告警引擎
 
diff --git a/SHA256SUMS b/SHA256SUMS
index de90aa8..0cb430c 100644
--- a/SHA256SUMS
+++ b/SHA256SUMS
@@ -1,6 +1,6 @@
-162b3c8dee7576d0cd81ac9b4cd5c7f1051f8d1dc7f35fd8b3eeb2a932662d95  README.md
+72e5eabe3093fde436d9bbef417660ada81a52164f9697486dcbd73f5322c205  README.md
 72c46162c33f9587c6ccb01ad53fbaaf4ecec8cd21014b909e87e8707e253e36  app/oled_font_5x7.bin
-f750ec8189c14fb8a4cdadc691752ce757b9ab4e26784197ba09883aaa630b4c  app/pigway_pi_control.py
+319ee4dbeed007df5ff3ce60f5a4b24b950f797f595848917542862bcbcbbd7d  app/pigway_pi_control.py
 dfb1d083c9d64a5e0d6ccfa60a4ef5f71e83ea137ebc53b169a69f6b1458883f  config/pigway-pi-control.conf
 4c2816da08378f2927c746b70ecfa7d5312e1730c08727cd89e8c2801e707054  install.sh
 81aea0a89b298b2512fcb9bf6418618ba7a66474d425390cf95a0128c4093474  systemd/pigway-pi-control.service
diff --git a/app/pigway_pi_control.py b/app/pigway_pi_control.py
index 114f281..e9a5b07 100755
--- a/app/pigway_pi_control.py
+++ b/app/pigway_pi_control.py
@@ -488,6 +488,7 @@ class DisplayController:
         self.current_priority=0
         self.current_rgb_mode="OFF"
         self.owner_since=now
+        self.batch_depth=0
         self.stop_event=threading.Event()
         self.rgb_thread=threading.Thread(target=self._rgb_worker,name="rgb",daemon=True)
 
@@ -518,14 +519,23 @@ class DisplayController:
                             ("priority","severity","rgb_mode","title","l2","l3","l4","metadata"))
                 if not changed: request["last_changed"]=current["last_changed"]
                 self.requests[request_id]=request
-            self._arbitrate_locked()
+            if self.batch_depth==0: self._arbitrate_locked()
 
     def clear(self,request_id):
         if request_id=="NORMAL_HOME": return
         with self.lock:
             if self.requests.pop(request_id,None) is not None:
                 log("INFO","ALERT_RECOVERED",alert=request_id)
-                self._arbitrate_locked()
+                if self.batch_depth==0: self._arbitrate_locked()
+
+    def begin_update(self):
+        with self.lock: self.batch_depth+=1
+
+    def end_update(self):
+        with self.lock:
+            if self.batch_depth<=0: raise RuntimeError("display update batch imbalance")
+            self.batch_depth-=1
+            if self.batch_depth==0: self._arbitrate_locked()
 
     def _arbitrate_locked(self):
         current=self.requests.get(self.current_owner_id)
@@ -654,7 +664,9 @@ try:
 
             c,t,m,d=latest
             display.update_home(c,t,m,d)
-            update_active_alerts(c,t,m,d,sample_elapsed)
+            display.begin_update()
+            try: update_active_alerts(c,t,m,d,sample_elapsed)
+            finally: display.end_update()
             if now-last_render >= OLED_REFRESH:
                 display.refresh()
                 last_render=now