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From:   Valentin Schneider <valentin.schneider@arm.com>
To:     Marc Zyngier <maz@kernel.org>
Cc:     linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        Thomas Gleixner <tglx@linutronix.de>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        Vincenzo Frascino <vincenzo.frascino@arm.com>
Subject: Re: [RFC PATCH v2 08/10] irqchip/gic-v3-its: Use irq_chip_ack_parent()
In-Reply-To: <87y2c0s748.wl-maz@kernel.org>
References: <20210525173255.620606-1-valentin.schneider@arm.com> <20210525173255.620606-9-valentin.schneider@arm.com> <87y2c0s748.wl-maz@kernel.org>
Date:   Tue, 01 Jun 2021 11:25:33 +0100
Message-ID: <87r1hlg9uq.mognet@arm.com>
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On 27/05/21 13:17, Marc Zyngier wrote:
> On Tue, 25 May 2021 18:32:53 +0100,
> Valentin Schneider <valentin.schneider@arm.com> wrote:
>> o make irq_chip_ack_parent() the default chip->irq_ack() via
>>   MSI_FLAG_USE_DEF_CHIP_OPS.
>
> Seem like a reasonable approach: how about a custom irq_ack() callback
> that iterates over the hierarchy until it finds an a non-NULL entry?
> Flows that don't use ack won't be impacted, users that need ack will
> provide one if they want, and the default will do something slightly
> slower, but at least unsurprising.
>

Sounds about right!

>> XXX: what about pMSI and fMSI ?
>
> Same thing. They are just bus-specific domains on top of the ITS
> domain, and must follow the same convention.
>
> However, this patch is perfectly acceptable to me (as long as you take
> care of platform and fsl -MSI).
>

Noted.

> Thanks,
>
>       M.
>
> --
> Without deviation from the norm, progress is not possible.