Re: [PATCH] serial: fix enable_irq_wake/disable_irq_wake imbalance in serial_core.c

[Andrew Morton <akpm@linux-foundation.org>]

On Mon, 19 May 2008 20:11:41 -0700
Arjan van de Ven <arjan@linux.intel.com> wrote:

> From: Arjan van de Ven <arjan@linux.intel.com>
> Subject: [PATCH] serial: fix enable_irq_wake/disable_irq_wake imbalance in serial_core.c
> 
> enable_irq_wake() and disable_irq_wake() need to be balanced.
> However, serial_core.c calls these for different conditions during
> the suspend and resume functions...
> 
> This is causing a regular WARN_ON() as found at
> http://www.kerneloops.org/search.php?search=set_irq_wake
> 
> This patch makes the conditions for triggering the _wake
> enable/disable sequence identical.
> 
> Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
> ---
>  drivers/serial/serial_core.c |    5 ++++-
>  1 files changed, 4 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c
> index eab0327..4df9ee1 100644
> --- a/drivers/serial/serial_core.c
> +++ b/drivers/serial/serial_core.c
> @@ -2054,6 +2054,8 @@ int uart_suspend_port(struct uart_driver *drv, struct uart_port *port)
>  int uart_resume_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);
>  
> @@ -2063,7 +2065,8 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *port)
>  		return 0;
>  	}
>  
> -	if (!port->suspended) {
> +	tty_dev = device_find_child(port->dev, &match, serial_match_port);
> +	if (!port->suspended && device_may_wakeup(tty_dev)) {
>  		disable_irq_wake(port->irq);
>  		mutex_unlock(&state->mutex);
>  		return 0;

erp, is that the easiest way of going from a uart_driver* to a device*?
Doing a lookup each time is a bit unusual.