linux-kernel - Re: [PATCH] simplefb: Disable and release clocks and regulators in destroy callback

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Message-ID: <CAMuHMdW+a_GRiSdvCoehScjePXXHNgr-gFXkkYfXJhrPwLiJZw@mail.gmail.com>
Date:   Wed, 7 Sep 2016 13:31:06 +0200
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     Hans de Goede <hdegoede@...hat.com>
Cc:     Chen-Yu Tsai <wens@...e.org>,
        Jean-Christophe Plagniol-Villard <plagnioj@...osoft.com>,
        Tomi Valkeinen <tomi.valkeinen@...com>,
        Linux Fbdev development list <linux-fbdev@...r.kernel.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: [PATCH] simplefb: Disable and release clocks and regulators in
 destroy callback

Hi Hans,

On Wed, Sep 7, 2016 at 1:29 PM, Hans de Goede <hdegoede@...hat.com> wrote:
> On 07-09-16 13:12, Geert Uytterhoeven wrote:
>> On Wed, Sep 7, 2016 at 11:09 AM, Chen-Yu Tsai <wens@...e.org> wrote:
>>> simplefb gets unregister when a proper framebuffer driver comes in and
>>> kicks it out. However the claimed clocks and regulators stay enabled
>>> as they are only released in the platform device remove function, which
>>> in theory would never get called.
>>>
>>> Move the clock/regulator cleanup into the framebuffer destroy callback,
>>> which gets called as part of the framebuffer unregister process.
>>
>>
>> Is this called before or after the new proper framebuffer driver kicks in?
>> If before, it may cause glitches.
>
>
> It is called by the new proper framebuffer driver's probe method,
> so it can make sure that it has already claimed / enabled the
> clocks/regulators before it calls remove_conlicting_framebuffers,
> avoiding the glitch.

OK, thx!

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds