linux-kernel - Re: [PATCH] irqchip: omap-intc: fix spurious irq handling

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Message-ID: <alpine.DEB.2.11.1510191209110.4212@nanos>
Date:	Mon, 19 Oct 2015 12:13:26 +0200 (CEST)
From:	Thomas Gleixner <tglx@...utronix.de>
To:	Sekhar Nori <nsekhar@...com>
cc:	Tony Lindgren <tony@...mide.com>,
	Jason Cooper <jason@...edaemon.net>,
	Marc Zyngier <marc.zyngier@....com>,
	John Ogness <john.ogness@...utronix.de>,
	Felipe Balbi <balbi@...com>,
	Linux OMAP Mailing List <linux-omap@...r.kernel.org>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] irqchip: omap-intc: fix spurious irq handling

On Mon, 19 Oct 2015, Sekhar Nori wrote:
> +	/*
> +	 * A spurious IRQ can result if interrupt that triggered the
> +	 * sorting is no longer active during the sorting (10 INTC
> +	 * functional clock cycles after interrupt assertion). Or a
> +	 * change in interrupt mask affected the result during sorting
> +	 * time. There is no special handling required except ignoring
> +	 * the SIR register value just read and retrying.
> +	 * See section 6.2.5 of AM335x TRM Literature Number: SPRUH73K
> +	 */
> +	if ((irqnr & SPURIOUSIRQ_MASK) == SPURIOUSIRQ_MASK) {
> +		pr_debug_ratelimited("%s: spurious irq!\n", __func__);

I'd prefer that this is a pr_once() and the spurious interrupt counter
is incremented. That's far more useful as it gives you real
information about the frequency of the issue.

Thanks,

	tglx
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