linux-kernel - Re: [PATCH 2/2] pinctrl: single: remove misuse of IRQF_NO

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Date:	Thu, 3 Dec 2015 13:37:15 -0800
From:	Tony Lindgren <tony@...mide.com>
To:	Grygorii Strashko <grygorii.strashko@...com>
Cc:	Linus Walleij <linus.walleij@...aro.org>,
	Sudeep Holla <sudeep.holla@....com>,
	"linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	linux-omap@...r.kernel.org
Subject: Re: [PATCH 2/2] pinctrl: single: remove misuse of IRQF_NO_SUSPEND
 flag

* Grygorii Strashko <grygorii.strashko@...com> [151203 10:36]:
> 
> I think, this patch should not break our wake-up functionality.
> It will just change the moment when pcs_irq_handler() will be called:
> 
> before this change:
> - suspend_enter()
>   ....
>   - arch_suspend_enable_irqs();
>     - ^ right here
> 
> after this change:
> - suspend_enter()
>   ....
>   dpm_resume_noirq()
>   - resume_device_irqs()
>     ^ here
> 
> Correct? And as for me this is more safe.

I think there's more to it though. With both applied, it produces this on
coming back up from suspend:

PM: noirq resume of devices complete after 18.127 msecs
------------[ cut here ]------------
WARNING: CPU: 0 PID: 123 at kernel/irq/manage.c:605 irq_set_irq_wake+0xbc/0xfc()
Unbalanced IRQ 375 wake disable
Modules linked in: ledtrig_default_on leds_gpio led_class rtc_twl twl4030_wdt
CPU: 0 PID: 123 Comm: bash Tainted: G        W       4.4.0-rc3-dirty #2682
Hardware name: Generic OMAP36xx (Flattened Device Tree)
[<c0017df0>] (unwind_backtrace) from [<c0014084>] (show_stack+0x10/0x14)
<c0014084>] (show_stack) from [<c03492d0>] (dump_stack+0x84/0x9c)
[<c03492d0>] (dump_stack) from [<c003ca2c>] (warn_slowpath_common+0x7c/0xb8)
[<c003ca2c>] (warn_slowpath_common) from [<c003ca98>] (warn_slowpath_fmt+0x30/0x40)
[<c003ca98>] (warn_slowpath_fmt) from [<c009b66c>] (irq_set_irq_wake+0xbc/0xfc)
[<c009b66c>] (irq_set_irq_wake) from [<c03f0f1c>] (device_wakeup_disarm_wake_irqs+0x70/0x12c)
[<c03f0f1c>] (device_wakeup_disarm_wake_irqs) from [<c03ee4ac>] (dpm_resume_noirq+0x20c/0x2e4)
[<c03ee4ac>] (dpm_resume_noirq) from [<c0095e94>] (suspend_devices_and_enter+0x1e4/0x6bc)
[<c0095e94>] (suspend_devices_and_enter) from [<c00966c4>] (pm_suspend+0x358/0x4b8)
[<c00966c4>] (pm_suspend) from [<c0094fdc>] (state_store+0x64/0xb8)
[<c0094fdc>] (state_store) from [<c034b46c>] (kobj_attr_store+0x14/0x20)
[<c034b46c>] (kobj_attr_store) from [<c01ea4d8>] (sysfs_kf_write+0x4c/0x50)
[<c01ea4d8>] (sysfs_kf_write) from [<c01e9afc>] (kernfs_fop_write+0xbc/0x1cc)
[<c01e9afc>] (kernfs_fop_write) from [<c0171c7c>] (__vfs_write+0x24/0xd8)
[<c0171c7c>] (__vfs_write) from [<c0172520>] (vfs_write+0x94/0x154)
[<c0172520>] (vfs_write) from [<c0172d1c>] (SyS_write+0x40/0x94)
[<c0172d1c>] (SyS_write) from [<c000f760>] (ret_fast_syscall+0x0/0x1c)
---[ end trace 321b51565e161bee ]---

And these both need to be applied together when we have a fix for the above
as otherwise we'll get the lock recursion Sudeep mentioned in patch 2/2.

Regards,

Tony
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