linux-kernel - Re: [RESEND PATCH v2 1/2] soc: amlogic: add Meson GX VPU Domains driver

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Message-ID: <4f236610-22d5-b3ef-a5a7-1aba579a0791@baylibre.com>
Date:   Mon, 30 Oct 2017 17:47:46 +0100
From:   Neil Armstrong <narmstrong@...libre.com>
To:     Ulf Hansson <ulf.hansson@...aro.org>
Cc:     Kevin Hilman <khilman@...libre.com>,
        Carlo Caione <carlo@...one.org>,
        linux-pm@...ts.linux-foundation.org,
        "open list:ARM/Amlogic Meson..." <linux-amlogic@...ts.infradead.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [RESEND PATCH v2 1/2] soc: amlogic: add Meson GX VPU Domains
 driver

On 30/10/2017 16:40, Ulf Hansson wrote:
> 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.
> 
> [...]
> 
> Kind regards
> Uffe
> 

Hi,

I added a "powered" attribute to trace if power-on was done by the driver, but I only protected the shutdown call.... I should indeed protect it in the power_off call instead.

Neil