pollnotify: we should send poll events before semaphore incrementes.

arch/arm/src/sama5/sam_tsd.c

@@ -254,19 +254,6 @@ static void sam_tsd_notify(struct sam_tsd_s *priv)
 {
   int i;
 
-  /* If there are threads waiting for read data, then signal one of them
-   * that the read data is available.
-   */
-
-  if (priv->nwaiters > 0)
-    {
-      /* After posting this semaphore, we need to exit because the
-       * touchscreen is no longer available.
-       */
-
-      nxsem_post(&priv->waitsem);
-    }
-
   /* If there are threads waiting on poll() for touchscreen data to become
    * available, then wake them up now.  NOTE: we wake up all waiting threads
    * because we do not know that they are going to do.  If they all try to
@@ -283,6 +270,19 @@ static void sam_tsd_notify(struct sam_tsd_s *priv)
           nxsem_post(fds->sem);
         }
     }
+
+  /* If there are threads waiting for read data, then signal one of them
+   * that the read data is available.
+   */
+
+  if (priv->nwaiters > 0)
+    {
+      /* After posting this semaphore, we need to exit because the
+       * touchscreen is no longer available.
+       */
+
+      nxsem_post(&priv->waitsem);
+    }
 }
 
 /****************************************************************************

arch/sim/src/sim/up_touchscreen.c

@@ -181,20 +181,6 @@ static void up_notify(FAR struct up_dev_s *priv)
 {
   int i;
 
-  /* If there are threads waiting for read data, then signal one of them
-   * that the read data is available.
-   */
-
-  iinfo("contact=%d nwaiters=%d\n", priv->sample.contact, priv->nwaiters);
-  if (priv->nwaiters > 0)
-    {
-      /* After posting this semaphore, we need to exit because
-       * the touchscreen is no longer available.
-       */
-
-      nxsem_post(&priv->waitsem);
-    }
-
   /* If there are threads waiting on poll() for touchscreen data to become
    * available, then wake them up now.  NOTE: we wake up all waiting threads
    * because we do not know what they are going to do.  If they all try to
@@ -211,6 +197,20 @@ static void up_notify(FAR struct up_dev_s *priv)
           nxsem_post(fds->sem);
         }
     }
+
+  /* If there are threads waiting for read data, then signal one of them
+   * that the read data is available.
+   */
+
+  iinfo("contact=%d nwaiters=%d\n", priv->sample.contact, priv->nwaiters);
+  if (priv->nwaiters > 0)
+    {
+      /* After posting this semaphore, we need to exit because
+       * the touchscreen is no longer available.
+       */
+
+      nxsem_post(&priv->waitsem);
+    }
 }
 
 /****************************************************************************
@@ -239,7 +239,9 @@ static int up_sample(FAR struct up_dev_s *priv,
 
       if (sample->contact == CONTACT_UP)
         {
-          /* Next.. no contract.  Increment the ID so that next contact ID will be unique */
+          /* Next.. no contract.  Increment the ID so that next contact ID
+           * will be unique
+           */
 
           priv->sample.contact = CONTACT_NONE;
           priv->id++;

boards/arm/stm32/mikroe-stm32f4/src/stm32_touchscreen.c

@@ -605,19 +605,6 @@ static void tc_notify(FAR struct tc_dev_s *priv)
     }
 #endif
 
-  /* If there are threads waiting for read data, then signal one of them
-   * that the read data is available.
-   */
-
-  if (priv->nwaiters > 0)
-    {
-      /* After posting this semaphore, we need to exit because the
-       * touchscreen is no longer available.
-       */
-
-      nxsem_post(&priv->waitsem);
-    }
-
   /* If there are threads waiting on poll() for touchscreen data to become
    * available, then wake them up now.  NOTE: we wake up all waiting threads
    * because we do not know that they are going to do.  If they all try to
@@ -634,6 +621,19 @@ static void tc_notify(FAR struct tc_dev_s *priv)
           nxsem_post(fds->sem);
         }
     }
+
+  /* If there are threads waiting for read data, then signal one of them
+   * that the read data is available.
+   */
+
+  if (priv->nwaiters > 0)
+    {
+      /* After posting this semaphore, we need to exit because the
+       * touchscreen is no longer available.
+       */
+
+      nxsem_post(&priv->waitsem);
+    }
 }
 
 /****************************************************************************

boards/mips/pic32mx/pic32mx7mmb/src/pic32_touchscreen.c

@@ -491,19 +491,6 @@ static void tc_notify(FAR struct tc_dev_s *priv)
 {
   int i;
 
-  /* If there are threads waiting for read data, then signal one of them
-   * that the read data is available.
-   */
-
-  if (priv->nwaiters > 0)
-    {
-      /* After posting this semaphore, we need to exit because the
-       * touchscreen is no longer available.
-       */
-
-      nxsem_post(&priv->waitsem);
-    }
-
   /* If there are threads waiting on poll() for touchscreen data to become
    * available, then wake them up now.  NOTE: we wake up all waiting threads
    * because we do not know that they are going to do.
@@ -521,6 +508,19 @@ static void tc_notify(FAR struct tc_dev_s *priv)
           nxsem_post(fds->sem);
         }
     }
+
+  /* If there are threads waiting for read data, then signal one of them
+   * that the read data is available.
+   */
+
+  if (priv->nwaiters > 0)
+    {
+      /* After posting this semaphore, we need to exit because the
+       * touchscreen is no longer available.
+       */
+
+      nxsem_post(&priv->waitsem);
+    }
 }
 
 /****************************************************************************

drivers/analog/adc.c

@@ -487,6 +487,12 @@ static void adc_notify(FAR struct adc_dev_s *dev)
 {
   FAR struct adc_fifo_s *fifo = &dev->ad_recv;
 
+  /* If there are threads waiting on poll() for data to become available,
+   * then wake them up now.
+   */
+
+  adc_pollnotify(dev, POLLIN);
+
   /* If there are threads waiting for read data, then signal one of them
    * that the read data is available.
    */
@@ -495,12 +501,6 @@ static void adc_notify(FAR struct adc_dev_s *dev)
     {
       nxsem_post(&fifo->af_sem);
     }
-
-  /* If there are threads waiting on poll() for data to become available,
-   * then wake them up now.
-   */
-
-  adc_pollnotify(dev, POLLIN);
 }
 
 /****************************************************************************

drivers/can/can.c

@@ -1326,6 +1326,12 @@ int can_receive(FAR struct can_dev_s *dev, FAR struct can_hdr_s *hdr,
 
           fifo->rx_tail = nexttail;
 
+          /* Notify all poll/select waiters that they can read from the
+           * cd_recv buffer
+           */
+
+          can_pollnotify(dev, POLLIN);
+
           sval = 0;
           if (nxsem_get_value(&fifo->rx_sem, &sval) < 0)
             {
@@ -1349,12 +1355,6 @@ int can_receive(FAR struct can_dev_s *dev, FAR struct can_hdr_s *hdr,
             }
 
           errcode = OK;
-
-          /* Notify all poll/select waiters that they can read from the
-           * cd_recv buffer
-           */
-
-          can_pollnotify(dev, POLLIN);
         }
 #ifdef CONFIG_CAN_ERRORS
       else
@@ -1471,6 +1471,12 @@ int can_txdone(FAR struct can_dev_s *dev)
 
       can_xmit(dev);
 
+      /* Notify all poll/select waiters that they can write to the cd_xmit
+       * buffer
+       */
+
+      can_pollnotify(dev, POLLOUT);
+
       /* Are there any threads waiting for space in the TX FIFO? */
 
       if (dev->cd_ntxwaiters > 0)
@@ -1485,12 +1491,6 @@ int can_txdone(FAR struct can_dev_s *dev)
         }
     }
 
-  /* Notify all poll/select waiters that they can write to the cd_xmit
-   * buffer
-   */
-
-  can_pollnotify(dev, POLLOUT);
-
   return ret;
 }
 

drivers/input/ads7843e.c

@@ -294,19 +294,6 @@ static void ads7843e_notify(FAR struct ads7843e_dev_s *priv)
 {
   int i;
 
-  /* If there are threads waiting for read data, then signal one of them
-   * that the read data is available.
-   */
-
-  if (priv->nwaiters > 0)
-    {
-      /* After posting this semaphore, we need to exit because the ADS7843E
-       * is no longer available.
-       */
-
-      nxsem_post(&priv->waitsem);
-    }
-
   /* If there are threads waiting on poll() for ADS7843E data to become
    * available, then wake them up now.  NOTE: we wake up all waiting threads
    * because we do not know that they are going to do.  If they all try to
@@ -323,6 +310,19 @@ static void ads7843e_notify(FAR struct ads7843e_dev_s *priv)
           nxsem_post(fds->sem);
         }
     }
+
+  /* If there are threads waiting for read data, then signal one of them
+   * that the read data is available.
+   */
+
+  if (priv->nwaiters > 0)
+    {
+      /* After posting this semaphore, we need to exit because the ADS7843E
+       * is no longer available.
+       */
+
+      nxsem_post(&priv->waitsem);
+    }
 }
 
 /****************************************************************************

drivers/input/ft5x06.c

@@ -224,19 +224,6 @@ static void ft5x06_notify(FAR struct ft5x06_dev_s *priv)
 {
   int i;
 
-  /* If there are threads waiting for read data, then signal one of them
-   * that the read data is available.
-   */
-
-  if (priv->nwaiters > 0)
-    {
-      /* After posting this semaphore, we need to exit because the FT5x06
-       * is no longer available.
-       */
-
-      nxsem_post(&priv->waitsem);
-    }
-
   /* If there are threads waiting on poll() for FT5x06 data to become
    * available, then wake them up now.  NOTE: we wake up all waiting threads
    * because we do not know that they are going to do.  If they all try to
@@ -253,6 +240,19 @@ static void ft5x06_notify(FAR struct ft5x06_dev_s *priv)
           nxsem_post(fds->sem);
         }
     }
+
+  /* If there are threads waiting for read data, then signal one of them
+   * that the read data is available.
+   */
+
+  if (priv->nwaiters > 0)
+    {
+      /* After posting this semaphore, we need to exit because the FT5x06
+       * is no longer available.
+       */
+
+      nxsem_post(&priv->waitsem);
+    }
 }
 
 /****************************************************************************

drivers/input/max11802.c

@@ -253,19 +253,6 @@ static void max11802_notify(FAR struct max11802_dev_s *priv)
 {
   int i;
 
-  /* If there are threads waiting for read data, then signal one of them
-   * that the read data is available.
-   */
-
-  if (priv->nwaiters > 0)
-    {
-      /* After posting this semaphore, we need to exit because the sample
-       * is no longer available.
-       */
-
-      nxsem_post(&priv->waitsem);
-    }
-
   /* If there are threads waiting on poll() for MAX11802 data to become
    * available, then wake them up now.  NOTE: we wake up all waiting
    * threads because we do not know that they are going to do.  If they
@@ -282,6 +269,19 @@ static void max11802_notify(FAR struct max11802_dev_s *priv)
           nxsem_post(fds->sem);
         }
     }
+
+  /* If there are threads waiting for read data, then signal one of them
+   * that the read data is available.
+   */
+
+  if (priv->nwaiters > 0)
+    {
+      /* After posting this semaphore, we need to exit because the sample
+       * is no longer available.
+       */
+
+      nxsem_post(&priv->waitsem);
+    }
 }
 
 /****************************************************************************