[patch] Remove tty low_latency flag setting from drivers/char/

[patch] Remove tty low_latency flag setting from drivers/char/

[Chuck Ebbert]

From: Chuck Ebbert <cebbert@redhat.com>

Remove tty low_latency flag setting from drivers/char/.

The kernel oopses if this flag is set.

Signed-off-by: Chuck Ebbert <cebbert@redhat.com>

--- linux-2.6.30.noarch.orig/drivers/char/nozomi.c
+++ linux-2.6.30.noarch/drivers/char/nozomi.c
@@ -1591,8 +1591,6 @@ static int ntty_open(struct tty_struct *
 
 	/* Enable interrupt downlink for channel */
 	if (port->port.count == 1) {
-		/* FIXME: is this needed now ? */
-		tty->low_latency = 1;
 		tty->driver_data = port;
 		tty_port_tty_set(&port->port, tty);
 		DBG1("open: %d", port->token_dl);
--- linux-2.6.30.noarch.orig/drivers/char/mxser.c
+++ linux-2.6.30.noarch/drivers/char/mxser.c
@@ -1048,8 +1048,6 @@ static int mxser_open(struct tty_struct 
 	if (retval)
 		return retval;
 
-	/* unmark here for very high baud rate (ex. 921600 bps) used */
-	tty->low_latency = 1;
 	return 0;
 }
 
--- linux-2.6.30.noarch.orig/drivers/char/pcmcia/ipwireless/tty.c
+++ linux-2.6.30.noarch/drivers/char/pcmcia/ipwireless/tty.c
@@ -134,7 +134,6 @@ static int ipw_open(struct tty_struct *l
 
 	tty->linux_tty = linux_tty;
 	linux_tty->driver_data = tty;
-	linux_tty->low_latency = 1;
 
 	if (tty->tty_type == TTYTYPE_MODEM)
 		ipwireless_ppp_open(tty->network);

Re: [patch] Remove tty low_latency flag setting from drivers/char/

[Alan Cox]

> Remove tty low_latency flag setting from drivers/char/.
> 
> The kernel oopses if this flag is set.

ipwireless_network_packet_received is not called from an IRQ path but
from a sleeping one. Please provide a trace of whatever you see failing
with that one as it should be fine and that isn't a bug fix. It may or
may not need low_latency but something else is wrong if it matters.

> 
> Signed-off-by: Chuck Ebbert <cebbert@redhat.com>
> 
> --- linux-2.6.30.noarch.orig/drivers/char/nozomi.c
> +++ linux-2.6.30.noarch/drivers/char/nozomi.c
> @@ -1591,8 +1591,6 @@ static int ntty_open(struct tty_struct *
>  
>  	/* Enable interrupt downlink for channel */
>  	if (port->port.count == 1) {
> -		/* FIXME: is this needed now ? */
> -		tty->low_latency = 1;

This one is correct.

> --- linux-2.6.30.noarch.orig/drivers/char/mxser.c
> +++ linux-2.6.30.noarch/drivers/char/mxser.c
> @@ -1048,8 +1048,6 @@ static int mxser_open(struct tty_struct 
>  	if (retval)
>  		return retval;
>  
> -	/* unmark here for very high baud rate (ex. 921600 bps) used */
> -	tty->low_latency = 1;
>  	return 0;
>  }

As is this

Re: [patch] Remove tty low_latency flag setting from drivers/char/

[Chuck Ebbert]

On Mon, 22 Jun 2009 18:06:50 +0100
Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:

> > Remove tty low_latency flag setting from drivers/char/.
> > 
> > The kernel oopses if this flag is set.
> 
> ipwireless_network_packet_received is not called from an IRQ path but
> from a sleeping one. Please provide a trace of whatever you see failing
> with that one as it should be fine and that isn't a bug fix. It may or
> may not need low_latency but something else is wrong if it matters.
> 

I only saw oopses with the nozomi driver. I'll send another patch.
Should I send these patches to you or to Andrew or ?

Re: [patch] Remove tty low_latency flag setting from drivers/char/

[Alan Cox]

On Mon, 22 Jun 2009 13:25:49 -0400
Chuck Ebbert <cebbert@redhat.com> wrote:

> On Mon, 22 Jun 2009 18:06:50 +0100
> Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:
> 
> > > Remove tty low_latency flag setting from drivers/char/.
> > > 
> > > The kernel oopses if this flag is set.
> > 
> > ipwireless_network_packet_received is not called from an IRQ path but
> > from a sleeping one. Please provide a trace of whatever you see failing
> > with that one as it should be fine and that isn't a bug fix. It may or
> > may not need low_latency but something else is wrong if it matters.
> > 
> 
> I only saw oopses with the nozomi driver. I'll send another patch.
> Should I send these patches to you or to Andrew or ?

Send them to me and I'll get them to Linus ASAP.