linux-kernel - Re: [Regression] "irqdomain: Don't set type when mapping an IRQ" breaks nexus7 gpio buttons

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Message-ID: <a6b946bd-26f2-b257-aaa4-70018abe96f0@nvidia.com>
Date:	Mon, 1 Aug 2016 11:26:42 +0100
From:	Jon Hunter <jonathanh@...dia.com>
To:	John Stultz <john.stultz@...aro.org>,
	Marc Zyngier <marc.zyngier@....com>
CC:	Thomas Gleixner <tglx@...utronix.de>,
	lkml <linux-kernel@...r.kernel.org>,
	Bjorn Andersson <bjorn.andersson@...aro.org>
Subject: Re: [Regression] "irqdomain: Don't set type when mapping an IRQ"
 breaks nexus7 gpio buttons

Hi John,

On 30/07/16 05:39, John Stultz wrote:
> Hey Jon,
>   So after rebasing my nexus7 patch stack onto pre-4.8-rc1 tree, I
> noticed the power/volume buttons stopped working.
> 
> I did a manual rebased bisection and chased it down to your commit
> 1e2a7d78499e ("irqdomain: Don't set type when mapping an IRQ").
> 
> Reverting that patch makes things work again, so I wanted to see if
> there was any debugging info I could provide to try to help narrow
> down the problem here. (Sorry, I'd tinker myself with it some and try
> to debug the issue, but after burning my friday night on this, I'm
> eager to get away from the keyboard for the weekend).

Before this commit bad IRQ type settings in device-tree were not getting
reported and so failures to set the IRQ type were going unnoticed. It's
most likely a bad IRQ type settings somewhere.

As Thomas mentioned hopefully dmesg will shed a bit more light.

Otherwise it can be worth looking at the ->irq_set_type() function for
the irqchips in the path of the interrupt requested to see if any are
failing. Looking at the nexus7 (assuming qcom variant), it looks like
there are 3 irqchips in the path (pm8921 --> apq8064-pinctrl --> gic).
The pm8xxx_irq_set_type() could return a failure when setting up the IRQ
type and could be worth checking. It does not look like the set_type for
the apq8064-pinctrl should ever fail (apart from calling BUG() which
would be obvious). The gic can also return a failure for setting the
type, but I did not see anything at first glance that looks incorrect in
the dts.

If we can narrow down irqchip, then hopefully it will be clearer.

Cheers
Jon

-- 
nvpublic