Query hardware-buffer status in chars_in_buffer should the write fifo be
empty.
This is needed to make the tty layer wait for hardware buffers to drain
on close.
Signed-off-by: Johan Hovold <jhovold@xxxxxxxxx>
---
drivers/usb/serial/ti_usb_3410_5052.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/drivers/usb/serial/ti_usb_3410_5052.c b/drivers/usb/serial/ti_usb_3410_5052.c
index 3ed8eca..062b6d8 100644
--- a/drivers/usb/serial/ti_usb_3410_5052.c
+++ b/drivers/usb/serial/ti_usb_3410_5052.c
@@ -687,6 +687,8 @@ static int ti_chars_in_buffer(struct tty_struct *tty)
struct ti_port *tport = usb_get_serial_port_data(port);
int chars = 0;
unsigned long flags;
+ int ret;
+ u8 lsr;
if (tport == NULL)
return 0;
@@ -695,6 +697,12 @@ static int ti_chars_in_buffer(struct tty_struct *tty)
chars = kfifo_len(&tport->write_fifo);
spin_unlock_irqrestore(&tport->tp_lock, flags);
+ if (!chars) {
+ ret = ti_get_lsr(tport, &lsr);
+ if (!ret && !(lsr & TI_LSR_TX_EMPTY))
+ chars = 1;
+ }
+
dev_dbg(&port->dev, "%s - returns %d\n", __func__, chars);
return chars;
}
--
1.8.1.5
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