On Thu, Aug 07, 2014 at 12:16:59PM -0400, Murali Karicheri wrote: > On 08/07/2014 11:29 AM, Peter Hurley wrote: > >On 05/01/2014 03:04 PM, Murali Karicheri wrote: > >>8250 uart driver currently supports only software assisted hw flow > >>control. The software assisted hw flow control maintains a hw_stopped > >>flag in the tty structure to stop and start transmission and use modem > >>status interrupt for the event to drive the handshake signals. This is > >>not needed if hw has flow control capabilities. This patch adds a > >>DT attribute for enabling hw flow control for a uart port. Also skip > >>stop and start if this flag is present in flag field of the port > >>structure. > >> > >>Signed-off-by: Murali Karicheri<[email protected]> > >> > >>CC: Rob Herring<[email protected]> > >>CC: Pawel Moll<[email protected]> > >>CC: Mark Rutland<[email protected]> > >>CC: Ian Campbell<[email protected]> > >>CC: Kumar Gala<[email protected]> > >>CC: Randy Dunlap<[email protected]> > >>CC: Greg Kroah-Hartman<[email protected]> > >>CC: Jiri Slaby<[email protected]> > >>CC: Santosh Shilimkar<[email protected]> > >>--- > >> .../devicetree/bindings/serial/of-serial.txt | 1 + > >> drivers/tty/serial/8250/8250_core.c | 6 ++++-- > >> drivers/tty/serial/of_serial.c | 4 ++++ > >> drivers/tty/serial/serial_core.c | 12 +++++++++--- > >> 4 files changed, 18 insertions(+), 5 deletions(-) > >> > >[...] > > > >>diff --git a/drivers/tty/serial/serial_core.c > >>b/drivers/tty/serial/serial_core.c > >>index b68550d..851707a 100644 > >>--- a/drivers/tty/serial/serial_core.c > >>+++ b/drivers/tty/serial/serial_core.c > >>@@ -174,8 +174,12 @@ static int uart_port_startup(struct tty_struct *tty, > >>struct uart_state *state, > >> if (tty->termios.c_cflag& CBAUD) > >> uart_set_mctrl(uport, TIOCM_RTS | TIOCM_DTR); > >> } > >>- > >>- if (tty_port_cts_enabled(port)) { > >>+ /* > >>+ * if hw support flow control without software intervention, > >>+ * then skip the below check > >>+ */ > >>+ if (tty_port_cts_enabled(port)&& > >>+ !(uport->flags& UPF_HARD_FLOW)) { > >> spin_lock_irq(&uport->lock); > >> if (!(uport->ops->get_mctrl(uport)& TIOCM_CTS)) > >> tty->hw_stopped = 1; > >>@@ -2772,7 +2776,9 @@ void uart_handle_cts_change(struct uart_port *uport, > >>unsigned int status) > >> > >> uport->icount.cts++; > >> > >>- if (tty_port_cts_enabled(port)) { > >>+ /* skip below code if the hw flow control is supported */ > >>+ if (tty_port_cts_enabled(port)&& > >>+ !(uport->flags& UPF_HARD_FLOW)) { > >Why is a modem status interrupt being generated for DCTS > >if autoflow control is enabled? > > > >This should be: > > > > WARN_ON_ONCE(uport->flags& UPF_HARD_FLOW); > > > >to indicate a mis-configured driver/device. > This patch is already merged to the upstream branch and if you see any > issue, please > post a patch for review.
If someone points out a problem in a patch of yours that is accepted upstream, it is nice to provide a fix, otherwise I will just revert it upstream, as it looks to be incorrect. So, should I just revert it? greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
