Here is a patch against 2.6.21 which flushes the tty flip buffer on ioctl(TCFLSH) for input.
--- a/drivers/char/tty_io.c 2007-04-25 22:08:32.000000000 -0500 +++ b/drivers/char/tty_io.c 2007-05-04 09:30:01.000000000 -0500 @@ -365,6 +365,28 @@ static void tty_buffer_free(struct tty_s } /** + * tty_buffer_flush - flush full tty buffers + * @tty: tty to flush + * + * flush all the buffers containing receive data + * + * Locking: none + */ + +static void tty_buffer_flush(struct tty_struct *tty) +{ + struct tty_buffer *thead; + unsigned long flags; + + spin_lock_irqsave(&tty->buf.lock, flags); + while((thead = tty->buf.head) != NULL) { + tty->buf.head = thead->next; + tty_buffer_free(tty, thead); + } + spin_unlock_irqrestore(&tty->buf.lock, flags); +} + +/** * tty_buffer_find - find a free tty buffer * @tty: tty owning the buffer * @size: characters wanted @@ -1240,6 +1262,7 @@ void tty_ldisc_flush(struct tty_struct * ld->flush_buffer(tty); tty_ldisc_deref(ld); } + tty_buffer_flush(tty); } EXPORT_SYMBOL_GPL(tty_ldisc_flush); @@ -3336,6 +3359,15 @@ int tty_ioctl(struct inode * inode, stru case TIOCMBIC: case TIOCMBIS: return tty_tiocmset(tty, file, cmd, p); + case TCFLSH: + switch (arg) { + case TCIFLUSH: + case TCIOFLUSH: + /* flush tty buffer and allow ldisc to process ioctl */ + tty_buffer_flush(tty); + break; + } + break; } if (tty->driver->ioctl) { retval = (tty->driver->ioctl)(tty, file, cmd, arg); - 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/