On Wed, 12 Sep 2007, Andrew Morton wrote:

quoted text
> On Wed, 12 Sep 2007 20:50:10 +0200 (CEST)
> Guennadi Liakhovetski <g.liakhovetski@gmx.de> wrote:
> 
> > Enable wakeup from serial ports, make it run-time configurable over sysfs, 
> > e.g.,
> > 
> > echo enabled > /sys/devices/platform/serial8250.0/tty/ttyS0/power/wakeup
> > 
> > Requires
> > 
> > # CONFIG_SYSFS_DEPRECATED is not set
> > 
> > Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
> > 
> > ---

[snip]

quoted text
> > Also would be nice to test with a Natsemi UART, that can wake up 
> > the system, if such systems exist.
> 
> It would help if you could provide simple-to-follow steps which a tester
> should follow to perform this testing.

Ok, for anyone owning a system with a Natsemi UART and capable to suspend 
and resume it (you do not have to be able to resume it from the UART), 
would be great to have the patch below tested. For this you just have to 
apply the patch below, issue the above "echo" command to one of your 
Natsemi port, suspend and resume your system, and verify that your Natsemi 
port still works. If you are actually capable of waking up the system from 
that port, would be nice to test that as well.

Thanks
Guennadi

quoted text
> > diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c
> > index 9c57486..8a3d6ea 100644
> > --- a/drivers/serial/serial_core.c
> > +++ b/drivers/serial/serial_core.c
> > @@ -1934,9 +1934,24 @@ static void uart_change_pm(struct uart_state *state, int pm_state)
> >  	}
> >  }
> >  
> > +struct uart_match {
> > +	struct uart_port *port;
> > +	struct uart_driver *driver;
> > +};
> > +
> > +static int serial_match_port(struct device *dev, void *data)
> > +{
> > +	struct uart_match *match = data;
> > +	dev_t devt = MKDEV(match->driver->major, match->driver->minor) + match->port->line;
> > +
> > +	return dev->devt == devt; /* Actually, only one tty per port */
> > +}
> > +
> >  int uart_suspend_port(struct uart_driver *drv, struct uart_port *port)
> >  {
> >  	struct uart_state *state = drv->state + port->line;
> > +	struct device *tty_dev;
> > +	struct uart_match match = {port, drv};
> >  
> >  	mutex_lock(&state->mutex);
> >  
> > @@ -1947,6 +1962,15 @@ int uart_suspend_port(struct uart_driver *drv, struct uart_port *port)
> >  	}
> >  #endif
> >  
> > +	tty_dev = device_find_child(port->dev, &match, serial_match_port);
> > +	if (device_may_wakeup(tty_dev)) {
> > +		enable_irq_wake(port->irq);
> > +		put_device(tty_dev);
> > +		mutex_unlock(&state->mutex);
> > +		return 0;
> > +	}
> > +	port->suspended = 1;
> > +
> >  	if (state->info && state->info->flags & UIF_INITIALIZED) {
> >  		const struct uart_ops *ops = port->ops;
> >  
> > @@ -1995,6 +2019,13 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *port)
> >  	}
> >  #endif
> >  
> > +	if (!port->suspended) {
> > +		disable_irq_wake(port->irq);
> > +		mutex_unlock(&state->mutex);
> > +		return 0;
> > +	}
> > +	port->suspended = 0;
> > +
> >  	uart_change_pm(state, 0);
> >  
> >  	/*
> > @@ -2266,6 +2297,7 @@ int uart_add_one_port(struct uart_driver *drv, struct uart_port *port)
> >  {
> >  	struct uart_state *state;
> >  	int ret = 0;
> > +	struct device *tty_dev;
> >  
> >  	BUG_ON(in_interrupt());
> >  
> > @@ -2301,7 +2333,13 @@ int uart_add_one_port(struct uart_driver *drv, struct uart_port *port)
> >  	 * Register the port whether it's detected or not.  This allows
> >  	 * setserial to be used to alter this ports parameters.
> >  	 */
> > -	tty_register_device(drv->tty_driver, port->line, port->dev);
> > +	tty_dev = tty_register_device(drv->tty_driver, port->line, port->dev);
> > +	if (likely(!IS_ERR(tty_dev))) {
> > +		device_can_wakeup(tty_dev) = 1;
> > +		device_set_wakeup_enable(tty_dev, 0);
> > +	} else
> > +		printk(KERN_ERR "Cannot register tty device on line %d\n",
> > +		       port->line);
> >  
> >  	/*
> >  	 * If this driver supports console, and it hasn't been
> > diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
> > index 773d8d8..60dedc0 100644
> > --- a/include/linux/serial_core.h
> > +++ b/include/linux/serial_core.h
> > @@ -291,7 +291,8 @@ struct uart_port {
> >  	unsigned long		mapbase;		/* for ioremap */
> >  	struct device		*dev;			/* parent device */
> >  	unsigned char		hub6;			/* this should be in the 8250 driver */
> > -	unsigned char		unused[3];
> > +	unsigned char		suspended;
> > +	unsigned char		unused[2];
> >  	void			*private_data;		/* generic platform data pointer */
> >  };
> >  
> 

---
Guennadi Liakhovetski
-
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