[nuttx] branch master updated: driver/serial: Only enable tx interrupt if tx buffer is not empty

[pk...@apache.org]

This is an automated email from the ASF dual-hosted git repository.

pkarashchenko pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/nuttx.git


The following commit(s) were added to refs/heads/master by this push:
     new cfe6c4be8e driver/serial: Only enable tx interrupt if tx buffer is not empty
cfe6c4be8e is described below

commit cfe6c4be8e2ef6e5400502db640c1de3de0b2aee
Author: Huang Qi <hu...@xiaomi.com>
AuthorDate: Wed Mar 8 15:10:41 2023 +0800

    driver/serial: Only enable tx interrupt if tx buffer is not empty
    
    Fix https://github.com/apache/nuttx/issues/8731
    
    Signed-off-by: Huang Qi <hu...@xiaomi.com>
---
 drivers/serial/serial.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/serial/serial.c b/drivers/serial/serial.c
index 0f22ffb483..825e233601 100644
--- a/drivers/serial/serial.c
+++ b/drivers/serial/serial.c
@@ -776,6 +776,7 @@ static ssize_t uart_read(FAR struct file *filep,
 #endif
   irqstate_t flags;
   ssize_t recvd = 0;
+  bool echoed = false;
   int16_t tail;
   char ch;
   int ret;
@@ -924,6 +925,13 @@ static ssize_t uart_read(FAR struct file *filep,
                     }
 
                   uart_putxmitchar(dev, ch, true);
+
+                  /* Mark the tx buffer have echoed content here,
+                   * to avoid the tx buffer is empty such as special escape
+                   * sequence received, but enable the tx interrupt.
+                   */
+
+                  echoed = true;
                 }
 
               /* Skipping character count down */
@@ -1116,7 +1124,7 @@ static ssize_t uart_read(FAR struct file *filep,
         }
     }
 
-  if (recvd > 0)
+  if (echoed)
     {
 #ifdef CONFIG_SERIAL_TXDMA
       uart_dmatxavail(dev);