linux-kernel - Re: [PATCH 3/5] mmc: dw_mmc: Add exynos resume callback to clear WAKEUP

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Date:	Tue, 9 Jul 2013 12:09:42 -0700
From:	Doug Anderson <dianders@...omium.org>
To:	Chris Ball <cjb@...top.org>
Cc:	Olof Johansson <olof@...om.net>,
	Jaehoon Chung <jh80.chung@...sung.com>,
	Seungwon Jeon <tgih.jun@...sung.com>,
	James Hogan <james.hogan@...tec.com>,
	Grant Grundler <grundler@...omium.org>,
	Alim Akhtar <alim.akhtar@...sung.com>,
	Abhilash Kesavan <a.kesavan@...sung.com>,
	Tomasz Figa <tomasz.figa@...il.com>,
	Doug Anderson <dianders@...omium.org>,
	Kukjin Kim <kgene.kim@...sung.com>,
	"linux-mmc@...r.kernel.org" <linux-mmc@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	linux-samsung-soc <linux-samsung-soc@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 3/5] mmc: dw_mmc: Add exynos resume callback to clear WAKEUP_INT

Hi,

On Tue, Jul 9, 2013 at 10:31 AM, Doug Anderson <dianders@...omium.org> wrote:
> If the WAKEUP_INT is asserted at wakeup and not cleared, we'll end up
> looping around forever.
>
> Signed-off-by: Doug Anderson <dianders@...omium.org>
> ---
>  drivers/mmc/host/dw_mmc-exynos.c | 23 +++++++++++++++++++++++
>  1 file changed, 23 insertions(+)

Grant just pointed out that the WAKEUP_INT is supposed to only be
enabled if bits 8, 9, or 10 are 1.  Our driver never sets those so we
_should_ never get a WAKEUP_INT.  Bits 8-10 are marked as RESERVED on
the exynos5420 manual, so the current guess is that they're broken on
that silicon but that sometimes the interrupt fires anyway.

In any case, it is still a reasonable thing to clear this interrupt at
wakeup if it has fired, even if we're on an exynos device without any
problems.

-Doug
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