From: Ivo Sieben <meltedpianoman@gmail.com>
To: Greg KH <gregkh@linuxfoundation.org>,
<linux-serial@vger.kernel.org>,
RT <linux-rt-users@vger.kernel.org>
Cc: Ivo Sieben <meltedpianoman@gmail.com>
Subject: [PATCH] [tty]: Report warning when low_latency flag is wrongly used
Date: Wed, 24 Oct 2012 14:35:42 +0200 [thread overview]
Message-ID: <1351082142-28633-1-git-send-email-meltedpianoman@gmail.com> (raw)
In-Reply-To: <20121023111659.6f4427c7@bob.linux.org.uk>
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 <meltedpianoman@gmail.com>
---
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 06725f5..6cf87d7 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)
--
1.7.9.5
next prev parent reply other threads:[~2012-10-24 12:35 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-20 14:02 [PATCH] tty: prevent unnecessary work queue lock checking on flip buffer copy Ivo Sieben
2012-09-20 16:33 ` Alan Cox
2012-09-24 9:33 ` Ivo Sieben
2012-09-25 12:01 ` [PATCH-v2] " Ivo Sieben
2012-09-25 13:06 ` Alan Cox
2012-09-25 14:39 ` Ivo Sieben
2012-09-25 14:47 ` Alan Cox
2012-09-27 11:58 ` [PATCH-v3] " Ivo Sieben
2012-09-27 12:02 ` Ivo Sieben
2012-10-22 23:47 ` Greg KH
2012-10-23 10:16 ` Alan Cox
2012-10-24 12:35 ` Ivo Sieben [this message]
2012-10-24 14:32 ` [PATCH] [tty]: Report warning when low_latency flag is wrongly used Paul Gortmaker
2012-10-24 18:22 ` [PATCH-v3] tty: prevent unnecessary work queue lock checking on flip buffer copy Greg KH
2012-09-27 13:15 ` Alan Cox
2012-09-27 16:53 ` Greg KH
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