[PATCH][RT] pty low latency

[PATCH][RT] pty low latency

[Sven-Thorsten Dietrich]

Subject: add hunks dropped in rt 2.6.31-rc5-rt1.1 forward port
From: patch-2.6.31-rc4-rt1
Signed-off-by: Sven-Thorsten Dietrich <sdietrich@suse.de>
--- a/drivers/char/pty.c
+++ b/drivers/char/pty.c
@@ -52,6 +52,7 @@ static void pty_close(struct tty_struct *tty, struct file *filp)
 		return;
 	tty->link->packet = 0;
 	set_bit(TTY_OTHER_CLOSED, &tty->link->flags);
+	tty_flip_buffer_push(tty->link);
 	wake_up_interruptible(&tty->link->read_wait);
 	wake_up_interruptible(&tty->link->write_wait);
 	if (tty->driver->subtype == PTY_TYPE_MASTER) {
@@ -207,6 +208,7 @@ static int pty_open(struct tty_struct *tty, struct file *filp)
 	clear_bit(TTY_OTHER_CLOSED, &tty->link->flags);
 	set_bit(TTY_THROTTLED, &tty->flags);
 	retval = 0;
+	tty->low_latency = 1;
 out:
 	return retval;
 }

Re: [PATCH][RT] pty low latency

[John Kacur]

On Thu, Aug 13, 2009 at 6:42 AM, Sven-Thorsten
Dietrich<sdietrich@novell.com> wrote:
>
> Subject: add hunks dropped in rt 2.6.31-rc5-rt1.1 forward port
> From: patch-2.6.31-rc4-rt1
> Signed-off-by: Sven-Thorsten Dietrich <sdietrich@suse.de>
> --- a/drivers/char/pty.c
> +++ b/drivers/char/pty.c
> @@ -52,6 +52,7 @@ static void pty_close(struct tty_struct *tty, struct file *filp)
>                return;
>        tty->link->packet = 0;
>        set_bit(TTY_OTHER_CLOSED, &tty->link->flags);
> +       tty_flip_buffer_push(tty->link);
>        wake_up_interruptible(&tty->link->read_wait);
>        wake_up_interruptible(&tty->link->write_wait);
>        if (tty->driver->subtype == PTY_TYPE_MASTER) {
> @@ -207,6 +208,7 @@ static int pty_open(struct tty_struct *tty, struct file *filp)
>        clear_bit(TTY_OTHER_CLOSED, &tty->link->flags);
>        set_bit(TTY_THROTTLED, &tty->flags);
>        retval = 0;
> +       tty->low_latency = 1;
>  out:
>        return retval;
>  }
>

Thank You - I applied this.

Re: [PATCH][RT] pty low latency

[Michael Guntsche]

Forgot CC'ing linux-kernel

-------- Original Message --------
Subject: Re: [PATCH][RT] pty low latency
Date: Fri, 14 Aug 2009 07:19:14 +0200
From: Michael Guntsche <mike@it-loops.com>
To: <sdietrich@novell.com>

Good morning,

I think this patch will break applications like pptp again. Please take a
look at

http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=e043e42bdb66885b3ac10d27a01ccb9972e2b0a3

I am not sure if there is a differnce with the RT patches. But I can assure
you that I get a kernel panic after 2 minutes of uptime with this patch
reverted in the vanilla kernel.

Kind regards,
Michael