Make sure hardware buffers are empty before returning 0.
This fixes a problem reported by Jarkko Huijts who noted that port close
returns before all data has been transferred.
Based on a solution proposed by Jarkko Huijts.
Reported-by: Jarkko Huijts <jarkko.huijts@xxxxxxxxx>
Signed-off-by: Johan Hovold <jhovold@xxxxxxxxx>
---
drivers/usb/serial/ftdi_sio.c | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)
diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c
index 3312d7a..03bf6d2 100644
--- a/drivers/usb/serial/ftdi_sio.c
+++ b/drivers/usb/serial/ftdi_sio.c
@@ -921,6 +921,7 @@ static void ftdi_set_termios(struct tty_struct *tty,
static int ftdi_tiocmget(struct tty_struct *tty);
static int ftdi_tiocmset(struct tty_struct *tty,
unsigned int set, unsigned int clear);
+static int ftdi_chars_in_buffer(struct tty_struct *tty);
static int ftdi_get_icount(struct tty_struct *tty,
struct serial_icounter_struct *icount);
static int ftdi_ioctl(struct tty_struct *tty,
@@ -950,6 +951,7 @@ static struct usb_serial_driver ftdi_sio_device = {
.open = ftdi_open,
.close = ftdi_close,
.dtr_rts = ftdi_dtr_rts,
+ .chars_in_buffer = ftdi_chars_in_buffer,
.throttle = usb_serial_generic_throttle,
.unthrottle = usb_serial_generic_unthrottle,
.process_read_urb = ftdi_process_read_urb,
@@ -2371,6 +2373,29 @@ static int ftdi_tiocmset(struct tty_struct *tty,
return update_mctrl(port, set, clear);
}
+static int ftdi_chars_in_buffer(struct tty_struct *tty)
+{
+ struct usb_serial_port *port = tty->driver_data;
+ unsigned char buf[2];
+ int count;
+ int ret;
+
+ count = usb_serial_generic_chars_in_buffer(tty);
+ if (count)
+ goto out;
+
+ /* Check if hardware buffer is empty. */
+ ret = ftdi_get_modem_status(tty, buf);
+ if (ret == 2) {
+ if (!(buf[1] & FTDI_RS_TEMT))
+ count = 1;
+ }
+out:
+ dev_dbg(&port->dev, "%s - %d\n", __func__, count);
+
+ return count;
+}
+
static int ftdi_get_icount(struct tty_struct *tty,
struct serial_icounter_struct *icount)
{
--
1.7.12
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