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From:   Chen-Yu Tsai <wenst@chromium.org>
Date:   Wed, 29 Sep 2021 10:28:15 +0800
Message-ID: <CAGXv+5GiQrxrcwCt0A6Dxxodd8JTqUvEJtZdzB=SUKJuWD_RVw@mail.gmail.com>
Subject: Re: [PATCH v3 2/4] drm/rockchip: dsi: Reconfigure hardware on resume()
To:     Brian Norris <briannorris@chromium.org>
Cc:     =?UTF-8?Q?Heiko_St=C3=BCbner?= <heiko@sntech.de>,
        LKML <linux-kernel@vger.kernel.org>,
        dri-devel <dri-devel@lists.freedesktop.org>,
        "open list:ARM/Rockchip SoC..." <linux-rockchip@lists.infradead.org>,
        Sandy Huang <hjc@rock-chips.com>,
        Thomas Hebb <tommyhebb@gmail.com>, stable@vger.kernel.org
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On Wed, Sep 29, 2021 at 5:36 AM Brian Norris <briannorris@chromium.org> wrote:
>
> Since commit 43c2de1002d2, we perform most HW configuration in the
> bind() function. This configuration may be lost on suspend/resume, so we
> need to call it again. That may lead to errors like this after system
> suspend/resume:
>
>   dw-mipi-dsi-rockchip ff968000.mipi: failed to write command FIFO
>   panel-kingdisplay-kd097d04 ff960000.mipi.0: failed write init cmds: -110
>
> Tested on Acer Chromebook Tab 10 (RK3399 Gru-Scarlet).
>
> Note that early mailing list versions of this driver borrowed Rockchip's
> downstream/BSP solution, to do HW configuration in mode_set() (which
> *is* called at the appropriate pre-enable() times), but that was
> discarded along the way. I've avoided that still, because mode_set()
> documentation doesn't suggest this kind of purpose as far as I can tell.
>
> Fixes: 43c2de1002d2 ("drm/rockchip: dsi: move all lane config except LCDC mux to bind()")
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Brian Norris <briannorris@chromium.org>

Reviewed-by: Chen-Yu Tsai <wenst@chromium.org>