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tty: rework break handling

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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>
This commit is contained in:
Alan Cox
2008-07-22 11:18:03 +01:00
committed by Linus Torvalds
parent abbe629ae4
commit 9e98966c7b
20 changed files with 97 additions and 84 deletions
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71
drivers/char/tty_io.c
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@@ -2849,16 +2849,29 @@ static int tiocsetd(struct tty_struct *tty, int __user *p)
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 @@ long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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 @@ long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
break;
}
/*
* Now do the stuff.
*/
switch (cmd) {
case TIOCSTI:
return tiocsti(tty, p);
@@ -3043,12 +3029,11 @@ long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
*/
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