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Date:   Mon, 5 Aug 2019 16:47:24 +0200
From:   Pavel Machek <pavel@denx.de>
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc:     linux-kernel@vger.kernel.org, stable@vger.kernel.org,
        Douglas Anderson <dianders@chromium.org>,
        Heiko Stuebner <heiko@sntech.de>,
        Sasha Levin <sashal@kernel.org>
Subject: Re: [PATCH 4.19 04/74] ARM: dts: rockchip: Mark that the rk3288
 timer might stop in suspend
Message-ID: <20190805144723.GC24265@amd>
References: <20190805124935.819068648@linuxfoundation.org>
 <20190805124936.173376284@linuxfoundation.org>
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On Mon 2019-08-05 15:02:17, Greg Kroah-Hartman wrote:
> [ Upstream commit 8ef1ba39a9fa53d2205e633bc9b21840a275908e ]
>=20
> This is similar to commit e6186820a745 ("arm64: dts: rockchip: Arch
> counter doesn't tick in system suspend").  Specifically on the rk3288
> it can be seen that the timer stops ticking in suspend if we end up
> running through the "osc_disable" path in rk3288_slp_mode_set().  In
> that path the 24 MHz clock will turn off and the timer stops.
>=20
> To test this, I ran this on a Chrome OS filesystem:
>   before=3D$(date); \
>   suspend_stress_test -c1 --suspend_min=3D30 --suspend_max=3D31; \
>   echo ${before}; date
>=20
> ...and I found that unless I plug in a device that requests USB wakeup
> to be active that the two calls to "date" would show that fewer than
> 30 seconds passed.
>=20
> NOTE: deep suspend (where the 24 MHz clock gets disabled) isn't
> supported yet on upstream Linux so this was tested on a downstream
> kernel.

I guess this does no harm, but deep sleep is unlikely to be suppored
in the stable kernels, so ... is it good idea there?

Thanks,
								Pavel

> --- a/arch/arm/boot/dts/rk3288.dtsi
> +++ b/arch/arm/boot/dts/rk3288.dtsi
> @@ -227,6 +227,7 @@
>  			     <GIC_PPI 11 (GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_HIGH)>,
>  			     <GIC_PPI 10 (GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_HIGH)>;
>  		clock-frequency =3D <24000000>;
> +		arm,no-tick-in-suspend;
>  	};
> =20
>  	timer: timer@ff810000 {

--=20
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo=
g.html

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