Re: [PATCH V2 02/14] irqchip/gic: WARN if setting the interrupt type for a PPI fails

From: Marc Zyngier
Date: Fri Apr 22 2016 - 04:49:58 EST

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@xxxxxxxxxx>

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

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