From 2c992cd73772bd0ef107536e8e3399d28493caa8 Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Thu, 18 Apr 2013 17:33:21 +0200 Subject: [PATCH] USB: ti_usb_3410_5052: query hardware-buffer status in chars_in_buffer 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 Signed-off-by: Greg Kroah-Hartman --- 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 3ed8ecafe597..062b6d872ea3 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; }