On 05/09/2014 13:06, Peter Hurley : > Hi Nicolas, > > On 09/05/2014 05:15 AM, Nicolas Ferre wrote: >> On 03/09/2014 18:09, Richard Genoud : >> Richard, >> >> Indeed it seems needed: >> >> Acked-by: Nicolas Ferre <nicolas.ferre@xxxxxxxxx> >> >> >> But BTW, I see just below a call to the atmel_enable_ms() function in >> atmel_set_ldisc(). My question is, shouldn't we also add this >> atmel_disable_ms() in the alternative that disables the PPS in this >> ldisc function? > > I have that change in another series but it has to wait for: Given the attractive enhancements that you describe below... I'll wait with pleasure ;-) > 1. another series that fixes races setting and clearing the controlling tty > (and reduces the footprint of tty_mutex) > 2. a series built on that which moves tty_lock() out from under tty_mutex > when reopening ttys > This allows the tty_lock to be held while closing the tty. > 3. a series which removes the ldisc flush from the serial core, among some > other locking fixes in the serial core. > This fixes a lock inversion between the termios_rwsem and the port mutex. > > All of which enables the set_ldisc() notification to be safely passed > termios so it can use UART_ENABLE_MS() and also claim the port mutex > to change the UPF_HARDPPS_CD flag, which is currently non-atomic and > may corrupt the uart port flags field. > > The series also claims the port lock around the *_enable_ms() in the > various set_ldisc() handlers to protect the hardware re-programming :) > > Right now, all of this is temporarily stuck on the most recent patch > series, which hinges on whether the kernel should continue to support > non-atomic byte stores. Thanks for sharing your plans. Bye, -- Nicolas Ferre -- 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
