From: Marc Zyngier <maz@kernel.org>
To: Biju Das <biju.das.jz@bp.renesas.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Prabhakar Mahadev Lad <prabhakar.mahadev-lad.rj@bp.renesas.com>,
Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>,
Geert Uytterhoeven <geert+renesas@glider.be>,
Biju Das <biju.das.au@gmail.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-renesas-soc@vger.kernel.org"
<linux-renesas-soc@vger.kernel.org>
Subject: Re: [PATCH 3/3] irqchip: renesas-rzg2l: Fix irq storm with edge trigger detection for TINT
Date: Tue, 19 Sep 2023 17:49:21 +0100 [thread overview]
Message-ID: <87a5ti3y7i.wl-maz@kernel.org> (raw)
In-Reply-To: <OS0PR01MB59228AD24951D49F3E639BFF86FAA@OS0PR01MB5922.jpnprd01.prod.outlook.com>
On Tue, 19 Sep 2023 17:32:05 +0100,
Biju Das <biju.das.jz@bp.renesas.com> wrote:
[...]
> > So you mean that you *already* lose interrupts across a disable followed by
> > an enable? I'm slightly puzzled...
>
> There is no interrupt lost at all.
>
> Currently this patch addresses 2 issues.
>
> Scenario 1: Extra interrupt when we select TINT source on enable_irq()
>
> Getting an extra interrupt, when client drivers calls enable_irq()
> during probe()/resume(). In this case, the irq handler on the Client
> driver just clear the interrupt status bit.
>
> Issue 2: IRQ storm when we select TINT source on enable_irq()
>
> Here as well, we are getting an extra interrupt, when client drivers
> calls enable_irq() during probe() and this Interrupts getting
> generated infinitely, when the client driver calls disable_irq() in
> irq handler and in in work queue calling enable_irq().
How do you know this is a spurious interrupt? For all you can tell,
you are just consuming an edge. I absolutely don't buy this
workaround, because you have no context that allows you to
discriminate between a real spurious interrupt and a normal interrupt
that lands while the interrupt line was masked.
> Currently we are not loosing interrupts, but we are getting additional
> Interrupt(phantom) which is causing the issue.
If you get an interrupt at probe time in the endpoint driver, that's
probably because the device is not in a quiescent state when the
interrupt is requested. And it is probably this that needs addressing.
M.
--
Without deviation from the norm, progress is not possible.
next prev parent reply other threads:[~2023-09-19 16:49 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-18 12:24 [PATCH 0/3] Fix IRQ storm with GPIO interrupts Biju Das
2023-09-18 12:24 ` [PATCH 1/3] irqchip: renesas-rzg2l: Fix logic to clear TINT interrupt source Biju Das
2023-09-18 12:38 ` Geert Uytterhoeven
2023-09-19 5:56 ` claudiu beznea
2023-09-24 9:31 ` [irqchip: irq/irqchip-fixes] " irqchip-bot for Biju Das
2023-09-18 12:24 ` [PATCH 2/3] irqchip: renesas-rzg2l: Mask interrupts for changing interrupt settings Biju Das
2023-09-24 9:27 ` Marc Zyngier
2023-09-25 8:51 ` Biju Das
2023-09-18 12:24 ` [PATCH 3/3] irqchip: renesas-rzg2l: Fix irq storm with edge trigger detection for TINT Biju Das
2023-09-19 14:37 ` Marc Zyngier
2023-09-19 15:24 ` Biju Das
2023-09-19 16:19 ` Marc Zyngier
2023-09-19 16:32 ` Biju Das
2023-09-19 16:49 ` Marc Zyngier [this message]
2023-09-19 17:06 ` Biju Das
2023-09-21 7:55 ` Marc Zyngier
2023-09-22 14:34 ` Biju Das
2023-10-06 10:46 ` Biju Das
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