From a37025b5c702aaf87191cd75fcc42c54454f16f5 Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Sun, 5 May 2013 20:32:30 +0200 Subject: [PATCH] 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 Signed-off-by: Johan Hovold Signed-off-by: Greg Kroah-Hartman --- drivers/usb/serial/ftdi_sio.c | 19 +++++-------------- 1 file changed, 5 insertions(+), 14 deletions(-) diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c index 1159fd4cd94d..a62a75a679cd 100644 --- a/drivers/usb/serial/ftdi_sio.c +++ b/drivers/usb/serial/ftdi_sio.c @@ -924,7 +924,7 @@ static int ftdi_tiocmset(struct tty_struct *tty, 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 @@ static struct usb_serial_driver ftdi_sio_device = { .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 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) { - 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