linux-kernel - Re: [PATCH] gpio: pcf875x: Revert "gpio: pcf857x: Propagate wake-up setting to parent irq controller"

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Date:	Thu, 14 May 2015 15:32:05 +0300
From:	"Grygorii.Strashko@...aro.org" <grygorii.strashko@...aro.org>
To:	Geert Uytterhoeven <geert@...ux-m68k.org>,
	Roger Quadros <rogerq@...com>
CC:	Linus Walleij <linus.walleij@...aro.org>,
	Alexandre Courbot <gnurou@...il.com>,
	"linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
	"linux-omap@...r.kernel.org" <linux-omap@...r.kernel.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] gpio: pcf875x: Revert "gpio: pcf857x: Propagate wake-up
 setting to parent irq controller"

Hi,

On 05/11/2015 08:36 PM, Geert Uytterhoeven wrote:
> On Mon, May 11, 2015 at 4:13 PM, Roger Quadros <rogerq@...com> wrote:
>> commit b80eef95beb0 ('gpio: pcf857x: Propagate wake-up setting to parent irq controller')
>> introduces the following recursive locking warning while suspending dra7-evm.
>>
>> The issue addressed by that commit has been already resolved by
>> commit 10a50f1ab5f0 ('genirq: Set IRQCHIP_SKIP_SET_WAKE flag for dummy_irq_chip')
> 
> That's not 100% correct: commit b80eef95beb0 ('gpio: pcf857x: Propagate wake-up
> setting to parent irq controller') fixes _two_ things:
>    1. warning due to missing irq_set_wake / IRQCHIP_SKIP_SET_WAKE,
>    2. propagating set_wake, so the parent interrupt controller stays awake, as
>       it's needed for wake-up,
> 
> Only the first issue is addressed by commit 10a50f1ab5f0 ('genirq: Set
> IRQCHIP_SKIP_SET_WAKE flag for dummy_irq_chip').
> 
>> and so let's revert commit b80eef95beb0 ('gpio: pcf857x: Propagate wake-up setting to parent irq controller')
>>
>> At least the recursive locking message no longer appears after the revert.
>>
>> [   30.591905] PM: Syncing filesystems ... done.
>> [   30.623060] Freezing user space processes ... (elapsed 0.003 seconds) done.
>> [   30.634470] Freezing remaining freezable tasks ... (elapsed 0.002 seconds) done.
>> [   30.658288] sd 0:0:0:0: [sda] Synchronizing SCSI cache
>> [   30.663678]
>> [   30.663681] =============================================
>> [   30.663683] [ INFO: possible recursive locking detected ]
>> [   30.663688] 4.1.0-rc3 #1115 Not tainted
>> [   30.663693] ---------------------------------------------
>> [   30.663697] suspend.sh/2319 is trying to acquire lock:
>> [   30.663719]  (class){......}, at: [<c0096ebc>] __irq_get_desc_lock+0x48/0x88
>> [   30.663722]
>> [   30.663722] but task is already holding lock:
>> [   30.663734]  (class){......}, at: [<c0096ebc>] __irq_get_desc_lock+0x48/0x88
> 
> Does this mean .set_irq_wake() cannot call irq_set_irq_wake()?
> Many GPIO drivers do that, as they need to propagate wake-up state to the
> parent interrupt controller?

As I remember, there was similar problem, so I found corresponding patch (just FYI)

ab2b926 mfd: Fix twl6030 lockdep recursion warning on setting wake IRQs

Not sure such kind of solution is the best choice (

-- 
regards,
-grygorii
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