linux-kernel - Re: [PATCH v3] irqchip/tango: Don't use incorrect irq_mask

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Message-ID: <6f0092f7-692f-4a15-1d95-40f4e59c8585@sigmadesigns.com>
Date:   Tue, 25 Jul 2017 15:26:40 +0200
From:   Marc Gonzalez <marc_gonzalez@...madesigns.com>
To:     Mans Rullgard <mans@...sr.com>, Doug Berger <opendmb@...il.com>
CC:     Thomas Gleixner <tglx@...utronix.de>,
        Marc Zyngier <marc.zyngier@....com>,
        Jason Cooper <jason@...edaemon.net>,
        Florian Fainelli <f.fainelli@...il.com>,
        LKML <linux-kernel@...r.kernel.org>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        Mason <slash.tmp@...e.fr>
Subject: Re: [PATCH v3] irqchip/tango: Don't use incorrect irq_mask_ack
 callback

On 25/07/2017 15:16, Måns Rullgård wrote:

> What happened to the patch adding the proper combined function?

It appears you're not CCed on v2.

https://patchwork.kernel.org/patch/9859799/

Doug wrote:
> Yes, you understand correctly.  The irq_mask_ack method is entirely
> optional and I assume that is why this issue went undetected for so
> long; however, it is slightly more efficient to combine the functions
> (even if the ack is unnecessary) which is why I chose to do so for my
> changes to the irqchip-brcmstb-l2 driver where I first discovered this
> issue.  How much value the improved efficiency has is certainly
> debatable, but interrupt handling is one area where people might care
> about such a small difference.  As the irqchip-tango driver maintainer
> you are welcome to decide whether or not the irq_mask_ack method makes
> sense to you.

My preference goes to leaving the irq_mask_ack callback undefined,
and let the irqchip framework use irq_mask and irq_ack instead.

Regards.