diff --git a/ChangeLog b/ChangeLog
index e294002..5ead08d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,18 @@
+2018-10-01  NIIBE Yutaka  <gniibe@fsij.org>
+
+	* contrib/ackbtn-stm32f103.c (PINCFG_EDGE): New.
+	(ackbtn_init): Use PINCFG_EDGE bit.
+	(ackbtn_enable): Configure the edge detector here.
+	(ackbtn_disable): Disable the edge detector.
+
+	* chopstx.c (chopstx_poll): Don't clear ->ready here.
+	(chx_cond_hook): Set ->ready = 0 when condition does
+	not meet.
+	(chopstx_claim_irq): Make sure clearing the interrupt.
+	(chx_intr_hook): Add the case when ->ready == 1.
+	(chopstx_intr_done): Set ->ready = 0.
+	(chx_join_hook): Set ->ready = 0 when it is still alive.
+
 2018-09-29  NIIBE Yutaka  <gniibe@fsij.org>
 
 	* VERSION: 1.10.
diff --git a/NEWS b/NEWS
index fc37fa6..38c3a34 100644
--- a/NEWS
+++ b/NEWS
@@ -1,6 +1,22 @@
 NEWS - Noteworthy changes
 
 
+* Major changes in Chopstx 1.11
+
+  Released 2018-10-01
+
+** Support calling chopstx_poll with intr->ready==1.
+In version <= 1.10, it assumed that all events should be handled after
+chopstx_poll, before calling chopstx_poll again.  With having
+chopstx_intr_done, it's OK now that chopstx_poll can be called again
+not examining/handling all poll descriptors, but only parts of them.
+
+** Acknowledge button change.
+In 1.10, the action was "memorized" by the edge detector.  Now, edge
+detector is disabled by ackbtn_disable, and it is enabled by
+ackbtn_enable.  So, the status is cleared correctly.
+
+
 * Major changes in Chopstx 1.10
 
   Released 2018-09-29
diff --git a/chopstx.c b/chopstx.c
index ce57312..997e52f 100644
--- a/chopstx.c
+++ b/chopstx.c
@@ -999,6 +999,7 @@ chopstx_claim_irq (chopstx_intr_t *intr, uint8_t irq_num)
   chx_cpu_sched_lock ();
   chx_spin_lock (&q_intr.lock);
   chx_disable_intr (irq_num);
+  chx_clr_intr (irq_num);
   chx_set_intr_prio (irq_num);
   chx_spin_unlock (&q_intr.lock);
   chx_cpu_sched_unlock ();
diff --git a/contrib/ackbtn-stm32f103.c b/contrib/ackbtn-stm32f103.c
index 3c392ff..dc28bb6 100644
--- a/contrib/ackbtn-stm32f103.c
+++ b/contrib/ackbtn-stm32f103.c
@@ -35,6 +35,8 @@
 #include "sys.h"
 
 static uint32_t pin_config;
+#define PINCFG_EDGE        0x80000000
+#define PINCFG_EDGE_RISING PINCFG_EDGE
 
 void
 ackbtn_init (chopstx_intr_t *intr)
@@ -42,7 +44,6 @@ ackbtn_init (chopstx_intr_t *intr)
   uint8_t irq_num;
   uint32_t afio_exticr_index;
   uint32_t afio_exticr_extiX_pY;
-  int rising_edge;
 
   switch (SYS_BOARD_ID)
     {
@@ -53,36 +54,43 @@ ackbtn_init (chopstx_intr_t *intr)
       afio_exticr_extiX_pY = AFIO_EXTICR1_EXTI3_PA;
       irq_num = EXTI3_IRQ;
       pin_config = 0x0008; /* EXTI_PR_PR3 == EXTI_IMR_MR3 == EXTI_RTSR_TR3 */
-      rising_edge = 1;
+      pin_config |= PINCFG_EDGE_RISING;
       break;
     }
 
-  chopstx_claim_irq (intr, irq_num);
-
   /* Configure EXTI line */
   if (afio_exticr_extiX_pY)
     AFIO->EXTICR[afio_exticr_index] |= afio_exticr_extiX_pY;
 
   /* Interrupt is masked, now */
-  EXTI->IMR &= ~pin_config;
+  EXTI->IMR &= ~(pin_config & ~PINCFG_EDGE);
 
-  /* Configure which edge is detected */
-  if (rising_edge)
-    EXTI->RTSR |= pin_config;
-  else
-    EXTI->FTSR |= pin_config;
+  chopstx_claim_irq (intr, irq_num);
 }
 
 void
 ackbtn_enable (void)
 {
-  EXTI->PR |= pin_config;	/* Clear pending interrupt */
-  EXTI->IMR |= pin_config;	/* Enable interrupt clearing the mask */
+  /* Clear pending interrupt */
+  EXTI->PR |= (pin_config & ~PINCFG_EDGE);
+  /* Enable interrupt, clearing the mask */
+  EXTI->IMR |= (pin_config & ~PINCFG_EDGE);
+
+  /* Configure which edge is detected */
+  if ((pin_config & PINCFG_EDGE))
+    EXTI->RTSR |= (pin_config & ~PINCFG_EDGE);
+  else
+    EXTI->FTSR |= (pin_config & ~PINCFG_EDGE);
 }
 
 void
 ackbtn_disable (void)
 {
-  EXTI->IMR &= ~pin_config;	/* Disable interrupt having the mask */
-  EXTI->PR |= pin_config;	/* Clear pending interrupt */
+  /* Disable interrupt having the mask */
+  EXTI->IMR &= ~(pin_config & ~PINCFG_EDGE);
+ /* Clear pending interrupt */
+
+  /* Disable edge detection */
+  EXTI->RTSR &= ~(pin_config & ~PINCFG_EDGE);
+  EXTI->FTSR &= ~(pin_config & ~PINCFG_EDGE);
 }