> I am writing an app that needs to control the > serial xmit in real-time. What I need is a notification > that the TTY output queue fillup (returned by TIOCOUTQ > ioctl) have dropped below the specified value. Not a supported feature basically. > I haven't found anything that can help implementing > this. If I can't get an async notification, the sync > notification will do too, like, for instance, the tcdrain() > call, but with the argument to specify the needed fillup, > below which the function will return. > If there is nothing like this, then even the notification > on every transmitted char will do. > But I've found nothing of the above. :( > > Any suggestions how the real-time control can be > implemented? Bascially even on the hardware that knows with this degree of granularity we don't propogate the information back in the manner you want. I'm not sure its a total loss however. Currently all the code basically does stuff in the tx path or tx irq handler along the line of if (bytes_left < constant) write_wakeup and I suspect if you made that adjustable and turned off the fifo and any other funnies you'd at least make it work for a sufficiently rigged demo. We could in theory put it in the tty_port in future too if its general purpose useful. Alan -- 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
