Subject: Re: [PATCH V2 02/14] irqchip/gic: WARN if setting the interrupt type
 for a PPI fails
To: Jon Hunter <jonathanh@nvidia.com>, Thomas Gleixner <tglx@linutronix.de>,
        Jason Cooper <jason@lakedaemon.net>, Rob Herring <robh+dt@kernel.org>,
        Pawel Moll <pawel.moll@arm.com>, Mark Rutland <mark.rutland@arm.com>,
        Ian Campbell <ijc+devicetree@hellion.org.uk>,
        Kumar Gala <galak@codeaurora.org>,
        Stephen Warren <swarren@wwwdotorg.org>,
        Thierry Reding <thierry.reding@gmail.com>
References: <1461150237-15580-1-git-send-email-jonathanh@nvidia.com>
 <1461150237-15580-3-git-send-email-jonathanh@nvidia.com>
Cc: Kevin Hilman <khilman@kernel.org>,
        Geert Uytterhoeven <geert@linux-m68k.org>,
        Grygorii Strashko <grygorii.strashko@ti.com>,
        Lars-Peter Clausen <lars@metafoo.de>,
        Linus Walleij <linus.walleij@linaro.org>, linux-tegra@vger.kernel.org,
        linux-omap@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org
From: Marc Zyngier <marc.zyngier@arm.com>
Organization: ARM Ltd
Message-ID: <5719E5AA.9060504@arm.com>
Date: Fri, 22 Apr 2016 09:49:46 +0100
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On 20/04/16 12:03, Jon Hunter wrote:
> Setting the interrupt type for private peripheral interrupts (PPIs) may
> not be supported by a given GIC because it is IMPLEMENTATION DEFINED
> whether this is allowed. There is no way to know if setting the type is
> supported for a given GIC and so the value written is read back to
> verify it matches the desired configuration. If it does not match then
> an error is return.
> 
> There are cases where the interrupt configuration read from firmware
> (such as a device-tree blob), has been incorrect and hence
> gic_configure_irq() has returned an error. This error has gone
> undetected because the error code returned was ignored but the interrupt
> still worked fine because the configuration for the interrupt could not
> be overwritten.
> 
> Given that this has done undetected and that failing to set the
> configuration for a PPI may not be a catastrophic, don't return an error
> but WARN if we fail to configure a PPI. This will allows us to fix up
> any places in the kernel where we should be checking the return status
> and maintain backward compatibility with firmware images that may have
> incorrect PPI configurations.
> 
> Signed-off-by: Jon Hunter <jonathanh@nvidia.com>

Acked-by: Marc Zyngier <marc.zyngier@arm.com>

	M.
-- 
Jazz is not dead. It just smells funny...