From mboxrd@z Thu Jan  1 00:00:00 1970
From: khilman@baylibre.com (Kevin Hilman)
Date: Mon, 30 Oct 2017 17:56:33 +0100
Subject: [RESEND PATCH v2 1/2] soc: amlogic: add Meson GX VPU Domains
 driver
In-Reply-To: <CAPDyKFpCf50XRowGe3X5KpmhKrb99NTxOUQtz4RN4aemAVAJCA@mail.gmail.com>
 (Ulf Hansson's message of "Mon, 30 Oct 2017 16:40:07 +0100")
References: <1509208583-30349-1-git-send-email-narmstrong@baylibre.com>
 <1509208583-30349-2-git-send-email-narmstrong@baylibre.com>
 <CAPDyKFpCf50XRowGe3X5KpmhKrb99NTxOUQtz4RN4aemAVAJCA@mail.gmail.com>
Message-ID: <7ho9ootvzy.fsf@baylibre.com>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

Ulf Hansson <ulf.hansson@linaro.org> writes:

> Hi Neil,
>
> [...]
>
>> +
>> +       pm_genpd_init(&vpu_hdmi_pd.genpd, &simple_qos_governor,
>> +                     meson_gx_pwrc_vpu_get_power(&vpu_hdmi_pd));
>> +
>
> This means that you may initialize the genpd in powered on state.
>
> For that scenario, I think you will hit a clock unprepare/disable
> in-balance issue when genpd calls your ->power_off() callback, simply
> because you didn't call clk_prepare_enable() for the clocks first.

Yup, in my testing, I definitely hit this.

Kevin