linux-kernel - Re: [PATCH v2 6/6] irqchip: crossbar: fix irq masking at suspend

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Message-ID: <55CC6EB8.3050906@ti.com>
Date:	Thu, 13 Aug 2015 13:17:28 +0300
From:	Grygorii Strashko <grygorii.strashko@...com>
To:	Sudeep Holla <sudeep.holla@....com>,
	Marc Zyngier <Marc.Zyngier@....com>
CC:	"tglx@...utronix.de" <tglx@...utronix.de>,
	"tony@...mide.com" <tony@...mide.com>,
	"linux@....linux.org.uk" <linux@....linux.org.uk>,
	"jason@...edaemon.net" <jason@...edaemon.net>,
	"nsekhar@...com" <nsekhar@...com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"balbi@...com" <balbi@...com>,
	"linux-omap@...r.kernel.org" <linux-omap@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH v2 6/6] irqchip: crossbar: fix irq masking at suspend

On 08/13/2015 12:30 PM, Sudeep Holla wrote:
> 
> 
> On 12/08/15 18:46, Grygorii Strashko wrote:
>> All ARM GIC IRQs have to masked during suspend if they are not
>> wakeup source. Now this is not happen, since switching to
>> use IRQ domain hierarchy, because suspend_device_irq() only checks flags
>> in the last IRQ chip in hierarchy for IRQCHIP_MASK_ON_SUSPEND
>> bit set. And in the case of TI OMAP DRA7 the last IRQ chip is TI Crossbar
>> which do not have this flag set.
>>
>> In case of TI OMAP DRA7 the following IRQ hierarchy is defined:
>>    ARM GIC <- OMAP wakeupgen <- TI CBAR
>> ARM GIC - IRQCHIP_MASK_ON_SUSPEND=n
> 
> May be this won't affect your platform or this patch but even GIC marks
> IRQCHIP_MASK_ON_SUSPEND=y now since GIC doesn't provide any facility to
> configure the wakeup source and keeps all the interrupt source enabled.

That's true for next, bur not true for 4.2-rc6 or 4.1 :(

> 
> We have this flag enabled now as it's always safer to mask all the non
> wakeup interrupts are masked at the chip level when suspending.

Indeed, but that's do not work in case of IRQ domain hierarchy and
it's do not clear how should it work?
I've tried to describe this problem in cover letter actually.

> 
> Also the beginning of the commit message contradicts when you also say
> in the following statement IRQCHIP_MASK_ON_SUSPEND=n. So you may need to
> update the log.

I'll try to reword. What I've tried to mention that IRQs masking on
suspend is default expected behavior and that how it was before
switching to IRQ domain hierarchy.

"All ARM GIC IRQs have to masked during suspend if they are not
 wakeup source - this is expected behavior and that's how it was before
 switching to IRQ domain hierarchy. ..."
ok?

-- 
regards,
-grygorii
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