hci_ldisc: suspicious/buggy code

Hi!

hci_uart_set_flow_control() contains some rather suspicious code. AFAICT:

set = 0.

Then we do set &= (magic constant). But as set is 0, it stays zero. It just does not make sense. [Nor does it make sense to do |= on known value of zero just after else. But that's probably just some artifact of editing.]

(And if you edit the code anyway, temporary variable to store TIOCM_DTR | TIOCM_RTS | TIOCM_OUT1 | TIOCM_OUT2 | TIOCM_LOOP would make sense.)

Thanks,
Pavel

/* Flow control or un-flow control the device */
void hci_uart_set_flow_control(struct hci_uart *hu, bool enable)

{
	...
	unsigned int set = 0;
	unsigned int clear = 0;

	if (enable) {
	   	...
		set &= ~(TIOCM_OUT2 | TIOCM_RTS);
		clear = ~set;
		set &= TIOCM_DTR | TIOCM_RTS | TIOCM_OUT1 |
		       TIOCM_OUT2 | TIOCM_LOOP;
		clear &= TIOCM_DTR | TIOCM_RTS | TIOCM_OUT1 |
			 TIOCM_OUT2 | TIOCM_LOOP;
		status = tty->driver->ops->tiocmset(tty, set, clear);
		BT_DBG("Clearing RTS: %s", status ? "failed" : "success");
	} else {
	       ...	
		set |= (TIOCM_OUT2 | TIOCM_RTS);

(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

I think this might be the fix, but it breaks h4p protocol on n900...

Pavel

index 0506806..b549c47 100644
@@ -271,8 +271,8 @@ void hci_uart_set_rts(struct hci_uart *hu, bool enable)
 		status = tty->driver->ops->tiocmget(tty);
 		BT_DBG("Current tiocm 0x%x", status);
 
-		set &= ~(TIOCM_OUT2 | TIOCM_RTS);
-		clear = ~set;
+		clear |= (TIOCM_OUT2 | TIOCM_RTS);
+		set = ~clear;
 		set &= TIOCM_DTR | TIOCM_RTS | TIOCM_OUT1 |
 		       TIOCM_OUT2 | TIOCM_LOOP;
 		clear &= TIOCM_DTR | TIOCM_RTS | TIOCM_OUT1 |

(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html