From d643fb8511c5f7b9556a0daaa29b6ec2e7a46c44 Mon Sep 17 00:00:00 2001
From: SPRESENSE <41312067+SPRESENSE@users.noreply.github.com>
Date: Fri, 10 Feb 2023 13:35:48 +0900
Subject: [PATCH] arch: cxd56xx: Fix gnss poll when an event has already
 occurred

Fix an issue that poll with timeout=0 cannot detect events that have
already occurred.
---
 arch/arm/src/cxd56xx/cxd56_gnss.c | 28 +++++++++++++++++++++++++++-
 1 file changed, 27 insertions(+), 1 deletion(-)

diff --git a/arch/arm/src/cxd56xx/cxd56_gnss.c b/arch/arm/src/cxd56xx/cxd56_gnss.c
index ee44942318e..ac101812e13 100644
--- a/arch/arm/src/cxd56xx/cxd56_gnss.c
+++ b/arch/arm/src/cxd56xx/cxd56_gnss.c
@@ -170,6 +170,7 @@ struct cxd56_gnss_dev_s
   mutex_t                         ioctllock;
   sem_t                           apiwait;
   int                             apiret;
+  bool                            has_event;
 };
 
 /****************************************************************************
@@ -2178,6 +2179,23 @@ static int cxd56_gnss_get_1pps_output(struct file *filep,
  *  CXD56_GNSS signal handler and utils
  */
 
+/****************************************************************************
+ * Name: cxd56_gnss_pollnotify
+ *
+ * Description:
+ *   Notify POLLIN event for poll
+ *
+ * Input Parameters:
+ *   dev - Gnss device structure pointer
+ *
+ ****************************************************************************/
+
+static void cxd56_gnss_pollnotify(struct cxd56_gnss_dev_s *dev)
+{
+  poll_notify(dev->fds, CONFIG_CXD56_GNSS_NPOLLWAITERS, POLLIN);
+  dev->has_event = true;
+}
+
 /****************************************************************************
  * Name: cxd56_gnss_wait_notify
  *
@@ -2492,7 +2510,7 @@ static void cxd56_gnss_default_sighandler(uint32_t data, void *userdata)
       return;
     }
 
-  poll_notify(priv->fds, CONFIG_CXD56_GNSS_NPOLLWAITERS, POLLIN);
+  cxd56_gnss_pollnotify(priv);
 
   nxmutex_unlock(&priv->devlock);
 
@@ -3019,6 +3037,13 @@ static int cxd56_gnss_poll(struct file *filep, struct pollfd *fds,
           ret       = -EBUSY;
           goto errout;
         }
+
+      /* Should we immediately notify on any of the requested events? */
+
+      if (priv->has_event)
+        {
+          cxd56_gnss_pollnotify(priv);
+        }
     }
   else if (fds->priv)
     {
@@ -3030,6 +3055,7 @@ static int cxd56_gnss_poll(struct file *filep, struct pollfd *fds,
 
       *slot                = NULL;
       fds->priv            = NULL;
+      priv->has_event      = false;
     }
 
 errout: