RE: Unbalanced IRQ wake disable during resume from static suspend

[Santosh Shilimkar <santosh.shilimkar@ti.com>]

> -----Original Message-----
> From: Govindraj [mailto:govindraj.ti@gmail.com]
> Sent: Friday, December 03, 2010 4:51 PM
> To: Santosh Shilimkar
> Cc: Paul Walmsley; linux-omap@vger.kernel.org;
khilman@deeprootsystems.com
> Subject: Re: Unbalanced IRQ wake disable during resume from static
suspend
>
> On Fri, Dec 3, 2010 at 4:38 PM, Santosh Shilimkar
> <santosh.shilimkar@ti.com> wrote:
> >> -----Original Message-----
> >> From: Paul Walmsley [mailto:paul@pwsan.com]
> >> Sent: Friday, December 03, 2010 3:53 PM
> >> To: Santosh Shilimkar
> >> Cc: linux-omap@vger.kernel.org; Govindraj;
khilman@deeprootsystems.com
> >> Subject: RE: Unbalanced IRQ wake disable during resume from static
> > suspend
> >>
> >> Hello Santosh
> >>
> >> On Thu, 2 Dec 2010, Santosh Shilimkar wrote:
> >>
> >> > Just a wild guess here but is this because the 'set_wake' is
> >> > not setup and then fw might be returning some error whenever
> >> > driver invoke this API as part of enable_irq_wake() callback
> >> >
> >> > If that being the case, below patch might might help. Can
> >> > somebody try this out ?
> >>
> >> This patch might remove the warnings, but I doubt that it solves the
> > root
> >> cause.  In any case, it doesn't seem correct to unconditionally
return
> 0
> >> (success) from an omap_irq_wake() function, given that the OMAP INTC
> has
> >> no functionality in this regard.
> >>
> >> The real problem appears to be in drivers/serial/serial_core.c.
> >> uart_suspend_port() doesn't check the return value of
enable_irq_wake().
> >> Seems to me that it needs to save that return value somewhere and not
> >> bother calling disable_irq_wake() in uart_resume_port() if
> >> enable_irq_wake() returned an error.
> >>
> >> That's the patch that I'd suggest that you guys put together and send
> to
> >> the Linux serial people.
> >>
> > You are right Paul. This will actually fix the broken driver rather
than
> > masking it. Will spin a patch for the same
> >
>
> Hi Santosh/Paul,
>
> How about this patch?
Looks inline with what Paul suggested.

> [Tested on 3630SDP
>
> ---
> Regards,
> Govindraj.R
>
>
> From cb4e79a645b530f83f55d801ab054cc438ada0dd Mon Sep 17 00:00:00 2001
> From: Govindraj.R <govindraj.raja@ti.com>
> Date: Fri, 3 Dec 2010 16:42:14 +0530
> Subject: [PATCH] Serial: Unbalanced IRQ wake disable during resume
> from static suspend
>
> Check for return status for enable_irq_wake if irq_wake
> interface is not available then during resume unconditional
> disabling of irq_wake can throw below warning.
>
> ------------[ cut here ]------------
> WARNING: at kernel/irq/manage.c:382 set_irq_wake+0x80/0xe4()
> Unbalanced IRQ 72 wake disable
> Modules linked in:
> [<c0062a28>] (unwind_backtrace+0x0/0xec) from [<c0092260>]
> (warn_slowpath_common+0x4c/0x64)
> [<c0092260>] (warn_slowpath_common+0x4c/0x64) from [<c00922f8>]
> (warn_slowpath_fmt+0x2c/0x3c
> [<c00922f8>] (warn_slowpath_fmt+0x2c/0x3c) from [<c00d3238>]
> (set_irq_wake+0x80/0xe4)
> [<c00d3238>] (set_irq_wake+0x80/0xe4) from [<c029dd60>]
> (uart_resume_port+0x84/0x248)
> [<c029dd60>] (uart_resume_port+0x84/0x248) from [<c02a2338>]
> (serial_omap_resume+0x20/0x2c)
> [<c02a2338>] (serial_omap_resume+0x20/0x2c) from [<c02a92d4>]
> (platform_pm_resume+0x48/0x54)
> [<c02a92d4>] (platform_pm_resume+0x48/0x54) from [<c02abd1c>]
> (pm_op+0x6c/0xac)
> [<c02abd1c>] (pm_op+0x6c/0xac) from [<c02ac0fc>]
> (device_resume+0x58/0x10c)
> [<c02ac0fc>] (device_resume+0x58/0x10c) from [<c02ac2ec>]
> (dpm_resume_end+0xf4/0x360)
> [<c02ac2ec>] (dpm_resume_end+0xf4/0x360) from [<c00cf58c>]
> (suspend_devices_and_enter+0x1ac/0x200)
> [<c00cf58c>] (suspend_devices_and_enter+0x1ac/0x200) from [<c00cf6c0>]
> (enter_state+0xe0/0x138)
> [<c00cf6c0>] (enter_state+0xe0/0x138) from [<c00ced18>]
> (state_store+0x90/0xb8)
> [<c00ced18>] (state_store+0x90/0xb8) from [<c0243b98>]
> (kobj_attr_store+0x18/0x1c)
> [<c0243b98>] (kobj_attr_store+0x18/0x1c) from [<c0176128>]
> (sysfs_write_file+0x10c/0x144)
> [<c0176128>] (sysfs_write_file+0x10c/0x144) from [<c0125528>]
> (vfs_write+0xac/0x134)
> [<c0125528>] (vfs_write+0xac/0x134) from [<c012565c>]
> (sys_write+0x3c/0x68)
> [<c012565c>] (sys_write+0x3c/0x68) from [<c005bb00>]
> (ret_fast_syscall+0x0/0x3c)
> ---[ end trace 19fe50b7b47ba94f ]---
>
> Thus add a flag to check the return status for irq_wake
> based on flag disable the irq_wake
>
> Signed-off-by: Govindraj.R <govindraj.raja@ti.com>
> ---
>  drivers/serial/serial_core.c |    6 ++++--
>  include/linux/serial_core.h  |    1 +
>  2 files changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c
> index cd85112..0466815 100644
> --- a/drivers/serial/serial_core.c
> +++ b/drivers/serial/serial_core.c
> @@ -1990,7 +1990,8 @@ int uart_suspend_port(struct uart_driver *drv,
> struct uart_port *uport)
>
>  	tty_dev = device_find_child(uport->dev, &match,
serial_match_port);
>  	if (device_may_wakeup(tty_dev)) {
> -		enable_irq_wake(uport->irq);
> +		if (!enable_irq_wake(uport->irq))
> +			uport->irq_wake = 1;
>  		put_device(tty_dev);
>  		mutex_unlock(&port->mutex);
>  		return 0;
> @@ -2056,7 +2057,8 @@ int uart_resume_port(struct uart_driver *drv,
> struct uart_port *uport)
>
>  	tty_dev = device_find_child(uport->dev, &match,
serial_match_port);
>  	if (!uport->suspended && device_may_wakeup(tty_dev)) {
> -		disable_irq_wake(uport->irq);
> +		if (uport->irq_wake)
> +			disable_irq_wake(uport->irq);
>  		mutex_unlock(&port->mutex);
>  		return 0;
>  	}
> diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
> index 295e898..88e73c3 100644
> --- a/include/linux/serial_core.h
> +++ b/include/linux/serial_core.h
> @@ -359,6 +359,7 @@ struct uart_port {
>  	struct device		*dev;			/* parent device
*/
>  	unsigned char		hub6;			/* this should be
in the
> 8250 driver */
>  	unsigned char		suspended;
> +	unsigned char		irq_wake;		/* Irq_wakeup
Available */
>  	unsigned char		unused[2];
>  	void			*private_data;		/* generic
platform data
> pointer */
>  };
> --
> 1.7.1
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