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References: <20210928213552.1001939-1-briannorris@chromium.org> <20210928143413.v3.1.Ic2904d37f30013a7f3d8476203ad3733c186827e@changeid>
In-Reply-To: <20210928143413.v3.1.Ic2904d37f30013a7f3d8476203ad3733c186827e@changeid>
From:   Chen-Yu Tsai <wenst@chromium.org>
Date:   Wed, 29 Sep 2021 10:27:46 +0800
Message-ID: <CAGXv+5FO2GrH9BQ=ohH-oE_A6rKAoEfpbAB_1Qsq9v0vGJ+7ww@mail.gmail.com>
Subject: Re: [PATCH v3 1/4] drm/rockchip: dsi: Hold pm-runtime across bind/unbind
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>,
        aleksandr.o.makarov@gmail.com, stable@vger.kernel.org,
        =?UTF-8?B?TsOtY29sYXMgRiAuIFIgLiBBIC4gUHJhZG8=?= 
        <nfraprado@collabora.com>
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On Wed, Sep 29, 2021 at 5:36 AM Brian Norris <briannorris@chromium.org> wro=
te:
>
> In commit 43c2de1002d2, we moved most HW configuration to bind(), but we
> didn't move the runtime PM management. Therefore, depending on initial
> boot state, runtime-PM workqueue delays, and other timing factors, we
> may disable our power domain in between the hardware configuration
> (bind()) and when we enable the display. This can cause us to lose
> hardware state and fail to configure our display. For example:
>
>   dw-mipi-dsi-rockchip ff968000.mipi: failed to write command FIFO
>   panel-innolux-p079zca ff960000.mipi.0: failed to write command 0
>
> or:
>
>   dw-mipi-dsi-rockchip ff968000.mipi: failed to write command FIFO
>   panel-kingdisplay-kd097d04 ff960000.mipi.0: failed write init cmds: -11=
0
>
> We should match the runtime PM to the lifetime of the bind()/unbind()
> cycle.
>
> Tested on Acer Chrometab 10 (RK3399 Gru-Scarlet), with panel drivers
> built either as modules or built-in.
>
> Side notes: it seems one is more likely to see this problem when the
> panel driver is built into the kernel. I've also seen this problem
> bisect down to commits that simply changed Kconfig dependencies, because
> it changed the order in which driver init functions were compiled into
> the kernel, and therefore the ordering and timing of built-in device
> probe.
>
> Fixes: 43c2de1002d2 ("drm/rockchip: dsi: move all lane config except LCDC=
 mux to bind()")
> Link: https://lore.kernel.org/linux-rockchip/9aedfb528600ecf871885f7293ca=
4207c84d16c1.camel@gmail.com/
> Reported-by: <aleksandr.o.makarov@gmail.com>
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Brian Norris <briannorris@chromium.org>
> Tested-by: N=C3=ADcolas F. R. A. Prado <nfraprado@collabora.com>

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