Hi, 2012/9/20 Alan Cox <alan@xxxxxxxxxxxxxxx>: > > So now when the user sets tty->low_latency on these devices the machine > crashes ? > > This is the wrong direction - in fact we have a pile we need to move > the other way ! > > If they resolve to the same thing in hard RT patches fine, that's a > different question. Sorry, Allan you are probably right, but I don't get it... I agree that when the tty->low_latency flag is set on these machines, the drivers that were modified by my patch will behave differently: they will call the flush_to_ldisc() function directly instead of using the work queue. So that indeed introduces different functionality. But what I don't understand is how this would cause the machine to crash? Even when the flush_to_ldisc() function is called from hard IRQ context this would cause no problems: the flush_to_ldisc() function uses IRQ save spin locks instead of mutexes to protect it's critical section. Right? Furthermore the majority of TTY drivers currently already use the tty_flip_buffer_push() function. Regards, Ivo Sieben -- 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
