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authorSebastian Huber <sebastian.huber@embedded-brains.de>2013-06-10 12:36:44 (UTC)
committerSebastian Huber <sebastian.huber@embedded-brains.de>2013-06-12 14:11:25 (UTC)
commitfed92f5f67bcaeffa6cb6ceebf5ddfdbcaff7fb8 (patch)
treebb3edf6e2c9d1856a1a5fbecdb10a6b8e5893dbd
parent7338299c962812df21d68b409e7e28a458b4a9d9 (diff)
downloadrtems-fed92f5f67bcaeffa6cb6ceebf5ddfdbcaff7fb8.tar.bz2
termios: Notify driver about inactive transmit
Returning this state in the return value leads to race conditions on SMP. The inactive state notification must be inside the critical section.
-rw-r--r--cpukit/libcsupport/src/termios.c3
-rw-r--r--doc/bsp_howto/console.t6
2 files changed, 9 insertions, 0 deletions
diff --git a/cpukit/libcsupport/src/termios.c b/cpukit/libcsupport/src/termios.c
index 5c48915..1c87e6b 100644
--- a/cpukit/libcsupport/src/termios.c
+++ b/cpukit/libcsupport/src/termios.c
@@ -1332,6 +1332,7 @@ rtems_termios_refill_transmitter (struct rtems_termios_tty *tty)
wakeUpWriterTask = true;
}
+ (*tty->device.write) (tty->minor, NULL, 0);
nToSend = 0;
} else {
len = tty->t_dqlen;
@@ -1351,6 +1352,7 @@ rtems_termios_refill_transmitter (struct rtems_termios_tty *tty)
* Buffer has become empty
*/
tty->rawOutBufState = rob_idle;
+ (*tty->device.write) (tty->minor, NULL, 0);
nToSend = 0;
/*
@@ -1367,6 +1369,7 @@ rtems_termios_refill_transmitter (struct rtems_termios_tty *tty)
/* set flag, that output has been stopped */
tty->flow_ctrl |= FL_OSTOP;
tty->rawOutBufState = rob_busy; /*apm*/
+ (*tty->device.write) (tty->minor, NULL, 0);
nToSend = 0;
} else {
/*
diff --git a/doc/bsp_howto/console.t b/doc/bsp_howto/console.t
index f04a67f..555cf04 100644
--- a/doc/bsp_howto/console.t
+++ b/doc/bsp_howto/console.t
@@ -408,6 +408,12 @@ static ssize_t my_driver_interrupt_write(int minor, const char *buf, size_t n)
* characters in the device data structure.
*/
+ /*
+ * Termios will set n to zero to indicate that the transmitter is
+ * now inactive. The output buffer is empty in this case. The
+ * driver may disable the transmit interrupts now.
+ */
+
return 0;
@}
@end group