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From:   Doug Anderson <dianders@chromium.org>
Date:   Wed, 15 May 2019 09:22:56 -0700
Message-ID: <CAD=FV=W2BvvEx+sYji5pGAEwagD6uA20nCMKwiU=kD6FqkSLiw@mail.gmail.com>
Subject: Re: [PATCH 1/2] drm: bridge: dw-hdmi: Add hooks for suspend/resume
To:     Heiko Stuebner <heiko@sntech.de>, Sandy Huang <hjc@rock-chips.com>,
        Andrzej Hajda <a.hajda@samsung.com>,
        Laurent Pinchart <Laurent.pinchart@ideasonboard.com>
Cc:     "open list:ARM/Rockchip SoC..." <linux-rockchip@lists.infradead.org>,
        Neil Armstrong <narmstrong@baylibre.com>,
        Matthias Kaehlcke <mka@chromium.org>,
        Sean Paul <seanpaul@chromium.org>,
        Zheng Yang <zhengyang@rock-chips.com>,
        Sam Ravnborg <sam@ravnborg.org>,
        dri-devel <dri-devel@lists.freedesktop.org>,
        LKML <linux-kernel@vger.kernel.org>,
        =?UTF-8?B?VmlsbGUgU3lyasOkbMOk?= <ville.syrjala@linux.intel.com>,
        David Airlie <airlied@linux.ie>,
        Jernej Skrabec <jernej.skrabec@siol.net>,
        Daniel Vetter <daniel@ffwll.ch>
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Hi

From: Douglas Anderson <dianders@chromium.org>
Date: Thu, May 2, 2019 at 3:38 PM
To: Heiko Stuebner, Sandy Huang, Andrzej Hajda, Laurent Pinchart
Cc: <linux-rockchip@lists.infradead.org>, Neil Armstrong,
<mka@chromium.org>, Sean Paul, Douglas Anderson, Zheng Yang, Sam
Ravnborg, <dri-devel@lists.freedesktop.org>,
<linux-kernel@vger.kernel.org>, Ville Syrj=C3=A4l=C3=A4, David Airlie, Jern=
ej
Skrabec, Daniel Vetter

> On Rockchip rk3288-based Chromebooks when you do a suspend/resume
> cycle:
>
> 1. You lose the ability to detect an HDMI device being plugged in.
>
> 2. If you're using the i2c bus built in to dw_hdmi then it stops
> working.
>
> Let's add a hook to the core dw-hdmi driver so that we can call it in
> dw_hdmi-rockchip in the next commit.
>
> NOTE: the exact set of steps I've done here in resume come from
> looking at the normal dw_hdmi init sequence in upstream Linux plus the
> sequence that we did in downstream Chrome OS 3.14.  Testing show that
> it seems to work, but if an extra step is needed or something here is
> not needed we could improve it.
>
> Signed-off-by: Douglas Anderson <dianders@chromium.org>
> ---
>
>  drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 21 +++++++++++++++++++++
>  include/drm/bridge/dw_hdmi.h              |  3 +++
>  2 files changed, 24 insertions(+)

Did anyone have any thoughts on this patch series?  Thanks!  :-)

-Doug