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From: Marc Zyngier <marc.zyngier@arm.com>
To: Russell King - ARM Linux <linux@arm.linux.org.uk>
Cc: Liviu Dudau <Liviu.Dudau@arm.com>,
	Rob Herring <robh+dt@kernel.org>,
	Mark Rutland <Mark.Rutland@arm.com>,
	Ian Campbell <ijc+devicetree@hellion.org.uk>,
	Thomas Gleixner <tglx@linutronix.de>,
	Jason Cooper <jason@lakedaemon.net>,
	Haojian Zhuang <haojian.zhuang@linaro.org>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	LAKML <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH] irqchip: gic: Allow interrupt level to be set for PPIs.
Date: Mon, 01 Dec 2014 11:31:05 +0000	[thread overview]
Message-ID: <547C5179.5020505@arm.com> (raw)
In-Reply-To: <20141201112302.GC3836@n2100.arm.linux.org.uk>

On 01/12/14 11:23, Russell King - ARM Linux wrote:
> On Mon, Dec 01, 2014 at 11:19:41AM +0000, Marc Zyngier wrote:
>> Hi Russell,
>>
>> On 01/12/14 11:03, Russell King - ARM Linux wrote:
>>> If all you want to do is to bypass the following check, what's wrong
>>> with actually doing that:
>>>
>>> -	if (type != IRQ_TYPE_LEVEL_HIGH && type != IRQ_TYPE_EDGE_RISING)
>>> +	if (gicirq >= 32 && type != IRQ_TYPE_LEVEL_HIGH &&
>>> +	    type != IRQ_TYPE_EDGE_RISING)
>>> 		return -EINVAL;
>>>
>>
>> I think that will require some additional changes to gic_configure_irq
>> (in irq-gic-common.c).
> 
> I don't think so - gic_configure_irq() will treat it as a no-op as far
> as trying to configure the IRQ settings.

I agree. But that's following ARM's tradition of making PPIs
non-configurable. I seem to remember that there is at least one
occurrence of a GIC with configurable PPIs (Qualcomm, IIRC).

With this use case in mind, Liviu's patch allows an active-low interrupt
to be correctly configured as level, for example.

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...

  reply	other threads:[~2014-12-01 11:31 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-11-28 17:55 [PATCH] irqchip: gic: Allow interrupt level to be set for PPIs Liviu Dudau
2014-12-01 10:41 ` Russell King - ARM Linux
2014-12-01 10:46   ` Liviu Dudau
2014-12-01 11:03     ` Russell King - ARM Linux
2014-12-01 11:19       ` Marc Zyngier
2014-12-01 11:23         ` Russell King - ARM Linux
2014-12-01 11:31           ` Marc Zyngier [this message]
2014-12-01 11:54             ` Russell King - ARM Linux
2014-12-01 12:36               ` Liviu Dudau
2014-12-01 11:44           ` Liviu Dudau

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