Re: Unbalanced IRQ wake disable during resume from static suspend

[Kevin Hilman <khilman@deeprootsystems.com>]

Santosh Shilimkar <santosh.shilimkar@ti.com> writes:

[...]

> Here is the refreshed version with change log. Also
> attached the patch in case google mails raps it up.
>
> From 0170159ae34957efb839d9143123f7ced795f62e Mon Sep 17 00:00:00 2001
> From: Santosh Shilimkar <santosh.shilimkar@ti.com>
> Date: Thu, 2 Dec 2010 14:36:17 +0530
> Subject: [PATCH] omap: irq: Dummy handler for enable_irq_wake
>
> With PM enabled, enable_irq_wake() has a callback for
> interrupt controllers. But since omap INTC handler did not had this
> call back associated, it was always returning -ENXIO, which was
> breaking the existing drivers. This patch adds dummy handlers in
> in order to avoid breaking of existing drivers.

Can you describe a little more exacly how drivers were being broken
(e.g. describe why this caused unbalanced IRQs, etc.)

Other than that this looks like the right fix.

I guess this hasn't been seen before since we haven't tested the sysfs
wakeup interface for the omap-serial driver.  For on-chip OMAP UARTs,
using the sysfs interface isn't needed as the serial core is already
doing device_init_wakeup(dev, true);

Kevin

> Without this patch you get below warnings with wakeup enabled on devices
>
> ------------[ 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+0xe0/0x1
> 38)
> [<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 ]---
>
> Reported-by: Paul Walmsley <paul@pwsan.com>
> Tested-by: Govindraj.R <govindraj.raja@ti.com>
>
> Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
> ---
>  arch/arm/mach-omap2/irq.c |   10 ++++++++++
>  1 files changed, 10 insertions(+), 0 deletions(-)
>
> diff --git a/arch/arm/mach-omap2/irq.c b/arch/arm/mach-omap2/irq.c
> index 32eeabe..6a964d3 100644
> --- a/arch/arm/mach-omap2/irq.c
> +++ b/arch/arm/mach-omap2/irq.c
> @@ -143,11 +143,21 @@ static void omap_mask_ack_irq(unsigned int irq)
>  	omap_ack_irq(irq);
>  }
>
> +#ifdef CONFIG_PM
> +static int omap_set_wake(unsigned int irq, unsigned int on)
> +{
> +	return 0;
> +}
> +#else
> +#define omap_set_wake NULL
> +#endif
> +
>  static struct irq_chip omap_irq_chip = {
>  	.name	= "INTC",
>  	.ack	= omap_mask_ack_irq,
>  	.mask	= omap_mask_irq,
>  	.unmask	= omap_unmask_irq,
> +	.set_wake = omap_set_wake,
>  };
>
>  static void __init omap_irq_bank_init_one(struct omap_irq_bank *bank)