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From: Thomas Gleixner <tglx@linutronix.de>
To: Mark Brown <broonie@kernel.org>, Krzysztof Kozlowski <krzk@kernel.org>
Cc: Vladimir Oltean <vladimir.oltean@nxp.com>,
	linux-spi@vger.kernel.org,
	"linux-kernel\@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Marc Kleine-Budde <mkl@pengutronix.de>,
	Wolfram Sang <wsa@kernel.org>,
	kernel@pengutronix.de
Subject: Re: [PATCH v2 3/3] genirq: Do not test disabled IRQs with DEBUG_SHIRQ
Date: Wed, 17 Jun 2020 11:30:44 +0200	[thread overview]
Message-ID: <87mu52ca4b.fsf@nanos.tec.linutronix.de> (raw)
In-Reply-To: <20200616103956.GL4447@sirena.org.uk>

Mark Brown <broonie@kernel.org> writes:
> 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.

Correct.

Shared interrupts are broken by design and I really can't understand why
hardware people still insist on them.

Thanks,

        tglx



  reply	other threads:[~2020-06-17  9:30 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-15  8:07 [PATCH v2 1/3] spi: spi-fsl-dspi: Fix external abort on interrupt in exit paths Krzysztof Kozlowski
2020-06-15  8:07 ` [PATCH v2 2/3] spi: spi-fsl-dspi: Initialize completion before possible interrupt Krzysztof Kozlowski
2020-06-15  8:07 ` [PATCH v2 3/3] genirq: Do not test disabled IRQs with DEBUG_SHIRQ Krzysztof Kozlowski
2020-06-15 12:08   ` Mark Brown
2020-06-16 10:11     ` Krzysztof Kozlowski
2020-06-16 10:39       ` Mark Brown
2020-06-17  9:30         ` Thomas Gleixner [this message]
2020-06-15  8:17 ` [PATCH v2 1/3] spi: spi-fsl-dspi: Fix external abort on interrupt in exit paths Marc Kleine-Budde
2020-06-15  9:23   ` Vladimir Oltean
2020-06-15 13:08     ` Krzysztof Kozlowski
2020-06-15 12:30   ` Mark Brown
2020-06-15 12:56     ` Vladimir Oltean
2020-06-15 13:10       ` Mark Brown
2020-06-15 13:12         ` Vladimir Oltean
2020-06-15 13:24           ` Mark Brown
2020-06-15 13:29             ` Vladimir Oltean
2020-06-15 13:36               ` Mark Brown
2020-06-15 13:41           ` Krzysztof Kozlowski
2020-06-15 14:23             ` Vladimir Oltean
2020-06-15 14:57               ` Krzysztof Kozlowski
2020-06-15 14:59                 ` Vladimir Oltean
2020-06-15 13:10       ` Krzysztof Kozlowski
2020-06-15 13:14         ` Vladimir Oltean
2020-06-15 13:28           ` Krzysztof Kozlowski
2020-06-15 13:33             ` Vladimir Oltean

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