On Sat, 22 Aug 2009, Alan Stern wrote: > Alan: > > There's a problem with the tty->ops->shutdown method. It needs to > release the last port reference owned by the current tty. But when was > that reference originally acquired? Evidently during the first time > serial_open() was called for the current tty. > > The problem is that serial_open() has no way to know if a particular > invocation is the first one for this tty! The ASYNCB_INITIALIZED flag > doesn't help, because it might not get set during the first call (i.e., > if an error occurs). > > To do this right, we need a flag in the tty_struct or the tty_port > which serial_open() can set when acquiring that first reference and > shutdown method can clear. Should I add such a flag? Never mind, I figured out an answer. Instead of a new flag, the routine can simply test whether or not tty->driver_data has been set. One more question: Under what circumstances should serial_open() increment port->port.count? It seems that this should happen on every call unless tty->driver_data is NULL or filp has been hung up. Is that right? I have a big patch almost ready for testing. Unfortunately I don't have access to my usual hardware right now, so I can't test it until the middle of the week. Bruno, if you like I will send you the patch when it looks okay and you can try it out. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
