console resume broken since ba15ab0e8de0d4439a91342ad52d55ca9e313f3d

console resume broken since ba15ab0e8de0d4439a91342ad52d55ca9e313f3d

[Sascha Hauer]

This patch fixes setting the console speed if console suspend is disabled
by breaking it if it is enabled, see below:

> commit ba15ab0e8de0d4439a91342ad52d55ca9e313f3d
> Author: Deepak Saxena <dsaxena@laptop.org>
> Date:   Sat Sep 19 13:13:33 2009 -0700
> 
>     Set proper console speed on resume if console suspend is disabled
>     
>     Commit b5b82df6, from May 2007, breaks no_console_suspend on the OLPC
>     XO laptop. Basically what happens is that upon returning from resume,
>     serial8250_resume_port() will reconfigure the port for high speed
>     mode and all console output will be garbled, making debug of the
>     resume path painful. This patch modifies uart_resume_port() to
>     reset the port to the state it was in before we suspended.
>     
>     Original patch by Marcelo Tosatti
>     
>     Second patch by Deepak then reworked by Alan to fit with the tty changes
>     before it got submitted. Also fixed the console path to set c_i/ospeed as
>     some drivers require the termios fields are valid
>     
>     Signed-off-by: Deepak Saxena <dsaxena@laptop.org>
>     Signed-off-by: Alan Cox <alan@linux.intel.com>
>     Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
> 
> diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c
> index 3fd0134..2514d00 100644
> --- a/drivers/serial/serial_core.c
> +++ b/drivers/serial/serial_core.c
> @@ -2068,11 +2068,29 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *uport)
>  	struct tty_port *port = &state->port;
>  	struct device *tty_dev;
>  	struct uart_match match = {uport, drv};
> +	struct ktermios termios;
>  
>  	mutex_lock(&port->mutex);
>  
>  	if (!console_suspend_enabled && uart_console(uport)) {
>  		/* no need to resume serial console, it wasn't suspended */
> +		/*
> +		 * First try to use the console cflag setting.
> +		 */
> +		memset(&termios, 0, sizeof(struct ktermios));
> +		termios.c_cflag = uport->cons->cflag;
> +		/*
> +		 * If that's unset, use the tty termios setting.
> +		 */
> +		if (termios.c_cflag == 0)
> +			termios = *state->port.tty->termios;
> +		else {
> +			termios.c_ispeed = termios.c_ospeed =
> +				tty_termios_input_baud_rate(&termios);
> +			termios.c_ispeed = termios.c_ospeed =
> +				tty_termios_baud_rate(&termios);
> +		}
> +		uport->ops->set_termios(uport, &termios, NULL);
>  		mutex_unlock(&port->mutex);
>  		return 0;
>  	}
> @@ -2089,20 +2107,6 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *uport)
>  	 * Re-enable the console device after suspending.
>  	 */
>  	if (uart_console(uport)) {
> -		struct ktermios termios;
> -
> -		/*
> -		 * First try to use the console cflag setting.
> -		 */
> -		memset(&termios, 0, sizeof(struct ktermios));
> -		termios.c_cflag = uport->cons->cflag;
> -
> -		/*
> -		 * If that's unset, use the tty termios setting.
> -		 */
> -		if (port->tty && termios.c_cflag == 0)
> -			termios = *port->tty->termios;
> -
>  		uart_change_pm(state, 0);
>  		uport->ops->set_termios(uport, &termios, NULL);


We call ->set_termios with an unitialized struct ktermios here.

Any ideas what to do?

Sascha

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Re: console resume broken since ba15ab0e8de0d4439a91342ad52d55ca9e313f3d

[Pavel Machek]

On Wed 2009-09-30 17:11:03, Sascha Hauer wrote:
> 
> This patch fixes setting the console speed if console suspend is disabled
> by breaking it if it is enabled, see below:
> 
> > commit ba15ab0e8de0d4439a91342ad52d55ca9e313f3d
> > Author: Deepak Saxena <dsaxena@laptop.org>
> > Date:   Sat Sep 19 13:13:33 2009 -0700
...
> > 
> >     Set proper console speed on resume if console suspend is disabled
> >     
> >     Commit b5b82df6, from May 2007, breaks no_console_suspend on the OLPC
> >     XO laptop. Basically what happens is that upon returning from resume,
> >     serial8250_resume_port() will reconfigure the port for high speed
> >     mode and all console output will be garbled, making debug of the
> >     resume path painful. This patch modifies uart_resume_port() to
> >     reset the port to the state it was in before we suspended.
> >     
> >     Original patch by Marcelo Tosatti
> > -		struct ktermios termios;
> > -
> > -		/*
> > -		 * First try to use the console cflag setting.
> > -		 */
> > -		memset(&termios, 0, sizeof(struct ktermios));
> > -		termios.c_cflag = uport->cons->cflag;
> > -
> > -		/*
> > -		 * If that's unset, use the tty termios setting.
> > -		 */
> > -		if (port->tty && termios.c_cflag == 0)
> > -			termios = *port->tty->termios;
> > -
> >  		uart_change_pm(state, 0);
> >  		uport->ops->set_termios(uport, &termios, NULL);
> 
> 
> We call ->set_termios with an unitialized struct ktermios here.
> 
> Any ideas what to do?

Revert the patch for now and make Deepak fix it properly?

Or maybe it is enough to just 'do nothing' in the 'if that's unset'
branch?


								Pavel

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