On Tue, Apr 16, 2019 at 1:03 AM Jan Kiszka <jan.kis...@siemens.com> wrote:
> > The serial device is set up this way:
> > struct rtser_config serial_config = {
> > .config_mask = 0xFFFF,
> > .baud_rate = 115200,
> > .parity = RTSER_NO_PARITY,
> > .data_bits = RTSER_8_BITS,
> > .stop_bits = RTSER_1_STOPB,
> > .handshake = RTSER_NO_HAND,
> > .fifo_depth = RTSER_DEF_FIFO_DEPTH, //RTSER_FIFO_DEPTH_8,
> > .reserved = 0,
> > .rx_timeout = 500000,
> > .tx_timeout = RTSER_DEF_TIMEOUT,
> > .event_timeout = 5000000,
> > .timestamp_history = RTSER_RX_TIMESTAMP_HISTORY,
> > .event_mask = RTSER_EVENT_RXPEND,
> > };
> > fd_tty[0] = rt_dev_open("rtser1", O_RDWR | O_NONBLOCK);
> > sret = rt_dev_ioctl(fd_tty[0], RTSER_RTIOC_SET_CONFIG, &serial_config);
> >
> > The application transmits a packet of about 75 bytes repeatedly from a
> > xenomai periodic task that wakes up at 125Hz repeatedly. Note that there
> is
> > also a small RX serial packet arriving so there is some full-duplex
> > overlap. On rtser0 this works fine, on the other serial ports the stall
> > happens after a few hours and my periodic xenomai task stops. There is no
> > xenomai watchdog message in dmesg. The code is repeatedly checking the
> > serial port status ioctl and there are no errors like framing errors etc.
> >
> > The periodic task is just a typical xenomai while() loop:
> > next += period_ns + adjust_ns;
> > rt_task_sleep_until(next);
> >
> > When my periodic task stops the kernel says the stack trace is:
> > [root@oyx ~]# cd /proc/1066/task/1075/
> > [root@oyx 1075]# cat stack
> > [<c112d058>] xnpod_suspend_thread+0x3d8/0x650
> > [<c1132f09>] xnsynch_sleep_on+0x139/0x320
> > [<c11a7f14>] rtdm_event_timedwait+0x2e4/0x390
> > [<e858ed3b>] rt_16550_write+0x35b/0x540 [xeno_16550A]
>
> This means the driver is stuck while writing because there are no more
> free
> entries in the hardware TX FIFO. Do you have hardware flow control
> enabled? Are
> you sure the that the receiving side is playing nicely?
> Jan
>
Well I'm not trying to use hardware flow control. Is hardware flow control
the xeno_16550A driver default?
I am using a 3-wire serial cable, no RTS/CTS wires at all, they are
floating.
At present my app only ever calls the ioctl RTSER_RTIOC_SET_CONFIG as
detailed above.
Are you saying I need to do an ioctl RTSER_RTIOC_SET_CONTROL and clear
control bit *RTSER_MCR_RTS* ?
I have another Xenomai app which has been running fine as a 3-wire serial
connection for about 4 years,
and it does not do an ioctl RTSER_RTIOC_SET_CONFIG either. Doesn't that
mean setting flow control is unnecessary?
-C Smith
