linux-kernel - Re: [RFC PATCH v2 1/3] PCI: rockchip: Add support for pcie wake irq

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Message-ID: <20170823015714.GA129497@google.com>
Date:   Tue, 22 Aug 2017 18:57:15 -0700
From:   Brian Norris <briannorris@...omium.org>
To:     jeffy <jeffy.chen@...k-chips.com>
Cc:     Tony Lindgren <tony@...mide.com>, linux-kernel@...r.kernel.org,
        bhelgaas@...gle.com, shawn.lin@...k-chips.com,
        dianders@...omium.org, Heiko Stuebner <heiko@...ech.de>,
        linux-pci@...r.kernel.org, linux-rockchip@...ts.infradead.org,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [RFC PATCH v2 1/3] PCI: rockchip: Add support for pcie wake irq

Hi Jeffy,

On Wed, Aug 23, 2017 at 09:32:39AM +0800, Jeffy Chen wrote:
> and for eage irq, maybe we should enable it right after(or before)
> the driver activate wake function(for example activate WOWLAN or
> WOLAN), otherwise would it be possible to miss some irqs(triggered
> before we actually enable the wake irq)?

I already mentioned this: for the PCI case, the specification explicitly
says that the WAKE# pin must remain asserted until the system wakes and
resets the link. So we don't have this problem.

But it is probably still useful to make sure there's a well-defined
point at which these interrupts are armed, so that if a device driver
does care, it can account for that. Just before suspend_noirq (as it is
today) is probably fine, so if there's some device-level handling that
needs to happen before we get to suspend (but after the wakeirq is
armed), it can go in the device or bus {suspend,resume}_noirq callbacks.

Brian