From: Uwe Bonnes <bon@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Uwe Bonnes <bon@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
drivers/usb/serial/ftdi_sio.c | 41 ++++++++++++++++-------------------------
1 files changed, 16 insertions(+), 25 deletions(-)
diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c
index 9699580..8fe034d 100644
--- a/drivers/usb/serial/ftdi_sio.c
+++ b/drivers/usb/serial/ftdi_sio.c
@@ -2328,6 +2328,8 @@ static int ftdi_ioctl(struct tty_struct *tty,
{
struct usb_serial_port *port = tty->driver_data;
struct ftdi_private *priv = usb_get_serial_port_data(port);
+ struct async_icount cnow;
+ struct async_icount cprev;
dbg("%s cmd 0x%04x", __func__, cmd);
@@ -2347,41 +2349,30 @@ static int ftdi_ioctl(struct tty_struct *tty,
* - mask passed in arg for lines of interest
* (use |'ed TIOCM_RNG/DSR/CD/CTS for masking)
* Caller should use TIOCGICOUNT to see which one it was.
- * (except that the driver doesn't support it !)
*
* This code is borrowed from linux/drivers/char/serial.c
*/
case TIOCMIWAIT:
- while (priv != NULL) {
+ cprev = priv->icount;
+ while (1) {
interruptible_sleep_on(&priv->delta_msr_wait);
/* see if a signal did it */
if (signal_pending(current))
return -ERESTARTSYS;
- else {
- char diff = priv->diff_status;
-
- if (diff == 0)
- return -EIO; /* no change => error */
-
- /* Consume all events */
- priv->diff_status = 0;
-
- /* Return 0 if caller wanted to know about
- these bits */
- if (((arg & TIOCM_RNG) && (diff & FTDI_RS0_RI)) ||
- ((arg & TIOCM_DSR) && (diff & FTDI_RS0_DSR)) ||
- ((arg & TIOCM_CD) && (diff & FTDI_RS0_RLSD)) ||
- ((arg & TIOCM_CTS) && (diff & FTDI_RS0_CTS))) {
- return 0;
- }
- /*
- * Otherwise caller can't care less about what
- * happened,and so we continue to wait for more
- * events.
- */
+ cnow = priv->icount;
+ if (cnow.rng == cprev.rng && cnow.dsr == cprev.dsr &&
+ cnow.dcd == cprev.dcd && cnow.cts == cprev.cts)
+ return -EIO; /* no change => error */
+ if (((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) ||
+ ((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) ||
+ ((arg & TIOCM_CD) && (cnow.dcd != cprev.dcd)) ||
+ ((arg & TIOCM_CTS) && (cnow.cts != cprev.cts))) {
+ return 0;
}
+ cprev = cnow;
}
- return 0;
+ /* not reached */
+ break;
case TIOCSERGETLSR:
return get_lsr_info(port, (struct serial_struct __user *)arg);
break;
--
1.7.7
--
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