USB: ftdi_sio: fix chars_in_buffer overhead
Use the new generic usb-serial wait_until_sent implementation to wait
for hardware buffers to drain.
This removes the need to check the hardware buffers in chars_in_buffer
and thus removes the overhead introduced by commit 6f602912 ("usb:
serial: ftdi_sio: Add missing chars_in_buffer function") without
breaking tty_wait_until_sent (used by, for example, tcdrain, tcsendbreak
and close).
Reported-by: Stas Sergeev <stsp@list.ru>
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c
index 1159fd4..a62a75a 100644
--- a/drivers/usb/serial/ftdi_sio.c
+++ b/drivers/usb/serial/ftdi_sio.c
@@ -924,7 +924,7 @@
static int ftdi_ioctl(struct tty_struct *tty,
unsigned int cmd, unsigned long arg);
static void ftdi_break_ctl(struct tty_struct *tty, int break_state);
-static int ftdi_chars_in_buffer(struct tty_struct *tty);
+static bool ftdi_tx_empty(struct usb_serial_port *port);
static int ftdi_get_modem_status(struct usb_serial_port *port,
unsigned char status[2]);
@@ -961,7 +961,7 @@
.ioctl = ftdi_ioctl,
.set_termios = ftdi_set_termios,
.break_ctl = ftdi_break_ctl,
- .chars_in_buffer = ftdi_chars_in_buffer,
+ .tx_empty = ftdi_tx_empty,
};
static struct usb_serial_driver * const serial_drivers[] = {
@@ -2056,27 +2056,18 @@
}
-static int ftdi_chars_in_buffer(struct tty_struct *tty)
+static bool ftdi_tx_empty(struct usb_serial_port *port)
{
- struct usb_serial_port *port = tty->driver_data;
- int chars;
unsigned char buf[2];
int ret;
- chars = usb_serial_generic_chars_in_buffer(tty);
- if (chars)
- goto out;
-
- /* Check if hardware buffer is empty. */
ret = ftdi_get_modem_status(port, buf);
if (ret == 2) {
if (!(buf[1] & FTDI_RS_TEMT))
- chars = 1;
+ return false;
}
-out:
- dev_dbg(&port->dev, "%s - %d\n", __func__, chars);
- return chars;
+ return true;
}
/* old_termios contains the original termios settings and tty->termios contains
