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From:   Doug Anderson <dianders@chromium.org>
Date:   Mon, 3 Jun 2019 11:41:42 -0700
Message-ID: <CAD=FV=U7_ek_z7UfaDn9My8UfZfpNom04OJHowoH-sNsGZQnxA@mail.gmail.com>
Subject: Re: [PATCH v2] mmc: dw_mmc: Disable SDIO interrupts while suspended
 to fix suspend/resume
To:     Ulf Hansson <ulf.hansson@linaro.org>
Cc:     Jaehoon Chung <jh80.chung@samsung.com>,
        Shawn Lin <shawn.lin@rock-chips.com>,
        Kalle Valo <kvalo@codeaurora.org>,
        Heiko Stuebner <heiko@sntech.de>,
        "open list:ARM/Rockchip SoC..." <linux-rockchip@lists.infradead.org>,
        Guenter Roeck <groeck@chromium.org>,
        Brian Norris <briannorris@chromium.org>,
        linux-wireless <linux-wireless@vger.kernel.org>,
        Sonny Rao <sonnyrao@chromium.org>,
        Emil Renner Berthing <emil.renner.berthing@gmail.com>,
        Matthias Kaehlcke <mka@chromium.org>,
        Ryan Case <ryandcase@chromium.org>,
        "# 4.0+" <stable@vger.kernel.org>,
        "linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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Ulf,

On Tue, May 28, 2019 at 3:49 PM Doug Anderson <dianders@chromium.org> wrote:
>
> > 1) As kind of stated above, did you consider a solution where the core
> > simply disables the SDIO IRQ in case it isn't enabled for system
> > wakeup? In this way all host drivers would benefit.
>
> I can give it a shot if you can give me a bunch of specific advice,
> but I only have access to a few devices doing anything with SDIO and
> they are all using Marvell or Broadcom on dw_mmc.
>
> In general I have no idea how SDIO wakeup (plumbed through the SD
> controller) would work.  As per below the only way I've seen it done
> is totally out-of-band.  ...and actually, I'm not sure I've actually
> ever seen even the out of band stuff truly work on a system myself.
> It's always been one of those "we should support wake on WiFi" but
> never made it all the way to implementation.  In any case, if there
> are examples of people plumbing wakeup through the SD controller I'd
> need to figure out how to not break them.  Just doing a solution for
> dw_mmc means I don't have to worry about this since dw_mmc definitely
> doesn't support SDIO wakeup.
>
> Maybe one way to get a more generic solution is if you had an idea for
> a patch that would work for many host controllers then you could post
> it and I could test to confirm that it's happy on dw_mmc?  ...similar
> to when you switched dw_mmc away from the old kthread-based SDIO
> stuff?

Unless you have time to help dig into all the possibilities here to
help understand how this should behave across all the different host
controllers / wakeup setups, maybe we could just land ${SUBJECT} patch
for now and when there is more clarity we can revisit?

Thanks!

-Doug