On Wed, Sep 10, 2014 at 08:45:01PM -0400, Peter Hurley wrote: > > I'm all for working around broken hardware in the kernel, but this seems > > like a very old issue, if it's even one at all, that we would be > > changing for no one who has reported it (that I know of...) > > How to unwedge a terminal comes up from time to time. Are you trying to unwedge a terminal using hardware flow control, or software flow control? For software flow control, this is a guarantee that we can make wrt to the behavior of tcflow(). For hardware flow control, we can't make any guarantees, whether it's with tcflow(TCOON) or tcflow(TCOOF); tcflow(TCOON). > It's possible that this may cause userspace breakage. Some app > may call tcflow(TCOON) thus accidently overriding the flow control > state when it would have had no effect before. It's very likely that an application that would be using tcflow() at all would first be sending a TCOOFF, and then sending a TCOON. So this doesn't worry me that much. Indeed, given that the definition of how TCION and TCIOFF is worded (send a START or STOP command), it's completely reasonable to interpret TCOON and TCOOFF as emulating what would happen if the system received a START or STOP command. (Note though that part of this is that Posix doesn't define CRTSCTS, so POSIX is entirely silent on the subject of hardware flow control). Cheers, - Ted -- 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
