From b8b345bae8cb6745f2afdd28bb2d93f9cf0d7f2c Mon Sep 17 00:00:00 2001 From: Ivo Sieben Date: Wed, 24 Oct 2012 14:35:42 +0200 Subject: [PATCH] TTY: Report warning when low_latency flag is wrongly used When a driver has the low_latency flag set and uses the schedule_flip() function to initiate copying data to the line discipline, a workqueue is scheduled in but never actually flushed. This is incorrect use of the low_latency flag (driver should not support the low_latency flag, or use the tty_flip_buffer_push() function instead). Make sure a warning is reported to catch incorrect use of the low_latency flag. This patch goes with: cee4ad1ed90a0959fc29f9d30a2526e5e9522cfa Signed-off-by: Ivo Sieben Signed-off-by: Greg Kroah-Hartman --- drivers/tty/tty_buffer.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c index 06725f5cc81..6cf87d7afb7 100644 --- a/drivers/tty/tty_buffer.c +++ b/drivers/tty/tty_buffer.c @@ -365,6 +365,7 @@ void tty_schedule_flip(struct tty_struct *tty) { struct tty_bufhead *buf = &tty->port->buf; unsigned long flags; + WARN_ON(tty->low_latency); spin_lock_irqsave(&buf->lock, flags); if (buf->tail != NULL) -- 2.46.0