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From:   Philip Chen <philipchen@chromium.org>
Date:   Thu, 21 Oct 2021 14:06:57 -0700
Message-ID: <CA+cxXh=jeT-t4o48Uv0xojsEP2erL6Aqw2XfYpnUa-SWdcVnfA@mail.gmail.com>
Subject: Re: [PATCH 1/2] drm/bridge: parade-ps8640: Enable runtime power management
To:     Doug Anderson <dianders@chromium.org>
Cc:     LKML <linux-kernel@vger.kernel.org>,
        Stephen Boyd <swboyd@chromium.org>,
        Andrzej Hajda <a.hajda@samsung.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        David Airlie <airlied@linux.ie>,
        Jernej Skrabec <jernej.skrabec@gmail.com>,
        Jonas Karlman <jonas@kwiboo.se>,
        Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
        Neil Armstrong <narmstrong@baylibre.com>,
        Robert Foss <robert.foss@linaro.org>,
        dri-devel <dri-devel@lists.freedesktop.org>
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Hi Doug,

On Mon, Oct 18, 2021 at 1:43 PM Doug Anderson <dianders@chromium.org> wrote:
>
> Hi,
>
> On Sat, Oct 16, 2021 at 9:57 AM Philip Chen <philipchen@chromium.org> wrote:
> >
> > @@ -319,81 +345,70 @@ static void ps8640_bridge_poweron(struct ps8640 *ps_bridge)
> >          */
> >         msleep(200);
> >
> > -       ret = regmap_read_poll_timeout(map, PAGE2_GPIO_H, status,
> > -                                      status & PS_GPIO9, 20 * 1000, 200 * 1000);
> > -
> > -       if (ret < 0) {
> > -               DRM_ERROR("failed read PAGE2_GPIO_H: %d\n", ret);
> > -               goto err_regulators_disable;
> > -       }
>
> Above the "msleep(200)" I see a comment that says "and then check the
> MCU ready flag every 20ms". That probably refers to the code that
> you're moving here. Maybe change the comment above the "msleep(200);"
> to something like this if you like it:
>
> /*
>  * Mystery 200 ms delay for the "MCU to be ready". It's unclear if
>  * this is truly necessary since the MCU will already signal that
>  * things are "good to go" by signaling HPD on "gpio 9". See
>  * ps8640_ensure_hpd(). For now we'll keep this mystery delay just in
>  * case.
>  */
>
Thanks for the review.
Added the comment in v2.
PTAL.

> Other than that this looks good to me, which isn't really a surprise
> since I was involved in helping with / reviewing early versions of
> this change. In any case, I'm happy with:
>
> Reviewed-by: Douglas Anderson <dianders@chromium.org>