tty: rework break handling
Some hardware needs to do break handling itself and may have partial
support only. Make break_ctl return an error code. Add a tty driver flag
so you can indicate driver hardware side break support.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index d27a08b..d94cd84 100644
--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -2849,16 +2849,29 @@
static int send_break(struct tty_struct *tty, unsigned int duration)
{
- if (tty_write_lock(tty, 0) < 0)
- return -EINTR;
- tty->ops->break_ctl(tty, -1);
- if (!signal_pending(current))
- msleep_interruptible(duration);
- tty->ops->break_ctl(tty, 0);
- tty_write_unlock(tty);
- if (signal_pending(current))
- return -EINTR;
- return 0;
+ int retval;
+
+ if (tty->ops->break_ctl == NULL)
+ return 0;
+
+ if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
+ retval = tty->ops->break_ctl(tty, duration);
+ else {
+ /* Do the work ourselves */
+ if (tty_write_lock(tty, 0) < 0)
+ return -EINTR;
+ retval = tty->ops->break_ctl(tty, -1);
+ if (retval)
+ goto out;
+ if (!signal_pending(current))
+ msleep_interruptible(duration);
+ retval = tty->ops->break_ctl(tty, 0);
+out:
+ tty_write_unlock(tty);
+ if (signal_pending(current))
+ retval = -EINTR;
+ }
+ return retval;
}
/**
@@ -2949,36 +2962,6 @@
tty->driver->subtype == PTY_TYPE_MASTER)
real_tty = tty->link;
- /*
- * Break handling by driver
- */
-
- retval = -EINVAL;
-
- if (!tty->ops->break_ctl) {
- switch (cmd) {
- case TIOCSBRK:
- case TIOCCBRK:
- if (tty->ops->ioctl)
- retval = tty->ops->ioctl(tty, file, cmd, arg);
- if (retval != -EINVAL && retval != -ENOIOCTLCMD)
- printk(KERN_WARNING "tty: driver %s needs updating to use break_ctl\n", tty->driver->name);
- return retval;
-
- /* These two ioctl's always return success; even if */
- /* the driver doesn't support them. */
- case TCSBRK:
- case TCSBRKP:
- if (!tty->ops->ioctl)
- return 0;
- retval = tty->ops->ioctl(tty, file, cmd, arg);
- if (retval != -EINVAL && retval != -ENOIOCTLCMD)
- printk(KERN_WARNING "tty: driver %s needs updating to use break_ctl\n", tty->driver->name);
- if (retval == -ENOIOCTLCMD)
- retval = 0;
- return retval;
- }
- }
/*
* Factor out some common prep work
@@ -3000,6 +2983,9 @@
break;
}
+ /*
+ * Now do the stuff.
+ */
switch (cmd) {
case TIOCSTI:
return tiocsti(tty, p);
@@ -3043,12 +3029,11 @@
*/
case TIOCSBRK: /* Turn break on, unconditionally */
if (tty->ops->break_ctl)
- tty->ops->break_ctl(tty, -1);
+ return tty->ops->break_ctl(tty, -1);
return 0;
-
case TIOCCBRK: /* Turn break off, unconditionally */
if (tty->ops->break_ctl)
- tty->ops->break_ctl(tty, 0);
+ return tty->ops->break_ctl(tty, 0);
return 0;
case TCSBRK: /* SVID version: non-zero arg --> no break */
/* non-zero arg means wait for all output data