On 09/10/2014 08:03 PM, Greg Kroah-Hartman wrote: > On Wed, Sep 10, 2014 at 05:28:19PM -0400, Peter Hurley wrote: >> This patch changes user-space behavior (for the better) but I'm not sure >> that it's consequence-free. Also, it might not be enough to unwedge the >> terminal if the driver got its own flow control state mangled. >> >> Thoughts? >> >> --- >% --- >> Subject: [RFC] tty: Always allow tcflow(TCOON) to unwedge terminal >> >> If terminal flow has been stopped, the terminal can be unwedged >> by: >> tcflow(fd, TCOOFF); >> tcflow(fd, TCOON); >> This works because tcflow(TCOOFF) ensures that ->flow_stopped is set, >> which allows tcflow(TCOON) to override the terminal flow state in >> __start_tty(). >> >> Instead, allow unwedging with only: >> tcflow(fd, TCOON); >> by disregarding the existing ->flow_stopped state. > > I don't see the benifit here, what are you trying to solve? Sending one > extra tcflow command? It's not common knowledge (and its certainly counterintuitive) that turning off output when output is already turned off (ie., tcflow(TCOOFF)) is the required trickery to unwedge a terminal. Unwedging directly seems the straightforward approach. Regards, Peter Hurley -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
