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References: <20210114124032.12765-1-pali@kernel.org> <20210114124032.12765-7-pali@kernel.org>
Subject: Re: [PATCH mvebu v2 06/10] clk: mvebu: armada-37xx-periph: Fix workaround for switching from L1 to L0
From:   Stephen Boyd <sboyd@kernel.org>
Cc:     Marek =?utf-8?q?Beh=C3=BAn?= <kabel@kernel.org>,
        Miquel Raynal <miquel.raynal@bootlin.com>,
        Tomasz Maciej Nowak <tmn505@gmail.com>,
        Luka Perkov <luka.perkov@sartura.hr>,
        Andre Heider <a.heider@gmail.com>,
        Vladimir Vid <vladimir.vid@sartura.hr>,
        Russell King <rmk+kernel@armlinux.org.uk>,
        =?utf-8?q?G=C3=A9rald?= Kerma <gerald@gk2.net>,
        Konstantin Porotchkin <kostap@marvell.com>
To:     Andrew Lunn <andrew@lunn.ch>,
        Gregory Clement <gregory.clement@bootlin.com>,
        Michael Turquette <mturquette@baylibre.com>,
        Pali =?utf-8?q?Roh=C3=A1r?= <pali@kernel.org>,
        linux-arm-kernel@lists.infradead.org, linux-clk@vger.kernel.org,
        linux-kernel@vger.kernel.org
Date:   Tue, 09 Feb 2021 17:58:31 -0800
Message-ID: <161292231125.418021.8310551532294838376@swboyd.mtv.corp.google.com>
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Quoting Pali Roh=C3=A1r (2021-01-14 04:40:28)
> When CPU frequency is at 250 MHz and set_rate() is called with 500 MHz (L=
1)
> quickly followed by a call with 1 GHz (L0), the CPU does not necessarily
> stay in L1 for at least 20ms as is required by Marvell errata.
>=20
> This situation happens frequently with the ondemand cpufreq governor and
> can be also reproduced with userspace governor. In most cases it causes C=
PU
> to crash.
>=20
> This change fixes the above issue and ensures that the CPU always stays in
> L1 for at least 20ms when switching from any state to L0.
>=20
> Signed-off-by: Marek Beh=C3=BAn <kabel@kernel.org>
> Signed-off-by: Pali Roh=C3=A1r <pali@kernel.org>
> Fixes: 61c40f35f5cd ("clk: mvebu: armada-37xx-periph: Fix switching CPU r=
ate from 300Mhz to 1.2GHz")
> Cc: stable@vger.kernel.org
> ---

Acked-by: Stephen Boyd <sboyd@kernel.org>