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Date: Wed, 31 May 2017 11:22:14 +0200 (CEST)
From: Thomas Gleixner <tglx@linutronix.de>
To: Brian Norris <briannorris@chromium.org>
cc: jeffy <jeffy.chen@rock-chips.com>, LKML <linux-kernel@vger.kernel.org>,
        dianders@chromium.org, tfiga@chromium.org,
        Johannes Berg <johannes.berg@intel.com>
Subject: Re: [PATCH] genirq: Check irq disabled & masked states in
 irq_shutdown
In-Reply-To: <20170530231956.GA25960@google.com>
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On Tue, 30 May 2017, Brian Norris wrote:
> On Sat, May 27, 2017 at 10:16:37AM +0200, Thomas Gleixner wrote:
> > On Sat, 27 May 2017, jeffy wrote:
> > > for example when a driver(drivers/net/wireless/marvell/mwifiex/main.c) try to
> > > do these:
> > > 
> > > devm_request_irq->irq_startup->irq_enable
> > > disable_irq                                     <-- disabled and masked
> > > devm_free_irq->irq_shutdown                     <-- disable it again
> > 
> > This driver is broken as hell.
> 
> No argument on the general statement :)
> 
> > It requests the interrupt _BEFORE_ the whole
> > thing is initialized. If there is a pending interrupt on that line, it will
> > explode nicely before it is able to disable the irq. But that's a different
> > problem.
> 
> For that particular interrupt, it's mostly an informational interrupt
> regarding wakeups. We don't do anything that could blow up there, except
> report a (spurious) wakeup event. (And this spurious wakeup event only
> occurs because the Wifi firmware may toggle its "wake" pin even when the
> system is already awake. A weird behavior...)
> 
> So yes, the pattern isn't great, but no, it's not going to blow up,
> AFAIK.

Fair enough.

Thanks,

	tglx