linux-kernel - Re: [PATCH v2 3/3] genirq: Do not test disabled IRQs with DEBUG

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Date:   Tue, 16 Jun 2020 11:39:56 +0100
From:   Mark Brown <broonie@...nel.org>
To:     Krzysztof Kozlowski <krzk@...nel.org>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Vladimir Oltean <vladimir.oltean@....com>,
        linux-spi@...r.kernel.org,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Marc Kleine-Budde <mkl@...gutronix.de>,
        Wolfram Sang <wsa@...nel.org>, kernel@...gutronix.de
Subject: Re: [PATCH v2 3/3] genirq: Do not test disabled IRQs with DEBUG_SHIRQ

On Tue, Jun 16, 2020 at 12:11:17PM +0200, Krzysztof Kozlowski wrote:
> On Mon, Jun 15, 2020 at 01:08:44PM +0100, Mark Brown wrote:
> > On Mon, Jun 15, 2020 at 10:07:19AM +0200, Krzysztof Kozlowski wrote:
> > > Testing events during freeing of disabled shared interrupts
> > > (CONFIG_DEBUG_SHIRQ) leads to false positives.  The driver disabled
> > > interrupts on purpose to be sure that they will not fire during device
> > > removal.

> > Surely the whole issue with shared IRQs that's being tested for here is
> > that when the interrupt is shared some other device connected to the
> > same interrupt line may trigger an interrupt regardless of what's going
> > on with this device?

> Yes. However if that device disabled the interrupt, it should not be
> fired for other users. In such case the testing does not point to a
> real issue.

To be honest I'd say that if you're disabling a shared interrupt that's
a bit of an issue regardless of anything else that's going on, it'll
disrupt other devices connected to it.

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