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References: <20230109084101.265664-1-treapking@chromium.org> <20230109084101.265664-3-treapking@chromium.org>
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From:   Chen-Yu Tsai <wenst@chromium.org>
Date:   Mon, 9 Jan 2023 17:47:26 +0800
Message-ID: <CAGXv+5FVfSUo6aTfS6tGPZLT3gqBRj5i0h0gKk5EdifPj-4L8w@mail.gmail.com>
Subject: Re: [PATCH v9 2/9] platform/chrome: cros_ec_typec: Purge blocking
 switch devlinks
To:     Pin-yen Lin <treapking@chromium.org>
Cc:     Andrzej Hajda <andrzej.hajda@intel.com>,
        Neil Armstrong <neil.armstrong@linaro.org>,
        Robert Foss <robert.foss@linaro.org>,
        Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
        Jonas Karlman <jonas@kwiboo.se>,
        Jernej Skrabec <jernej.skrabec@gmail.com>,
        David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Daniel Scally <djrscally@gmail.com>,
        Heikki Krogerus <heikki.krogerus@linux.intel.com>,
        Sakari Ailus <sakari.ailus@linux.intel.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "Rafael J . Wysocki" <rafael@kernel.org>,
        Prashant Malani <pmalani@chromium.org>,
        Benson Leung <bleung@chromium.org>,
        Guenter Roeck <groeck@chromium.org>,
        Marek Vasut <marex@denx.de>, devicetree@vger.kernel.org,
        =?UTF-8?B?TsOtY29sYXMgRiAuIFIgLiBBIC4gUHJhZG8=?= 
        <nfraprado@collabora.com>, linux-acpi@vger.kernel.org,
        Allen Chen <allen.chen@ite.com.tw>,
        Javier Martinez Canillas <javierm@redhat.com>,
        dri-devel@lists.freedesktop.org,
        Stephen Boyd <swboyd@chromium.org>,
        Thomas Zimmermann <tzimmermann@suse.de>,
        Hsin-Yi Wang <hsinyi@chromium.org>,
        chrome-platform@lists.linux.dev, Xin Ji <xji@analogixsemi.com>,
        linux-kernel@vger.kernel.org,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@collabora.com>
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On Mon, Jan 9, 2023 at 4:41 PM Pin-yen Lin <treapking@chromium.org> wrote:
>
> From: Prashant Malani <pmalani@chromium.org>
>
> When using OF graph, the fw_devlink code will create links between the
> individual port driver (cros-ec-typec here) and the parent device for
> a Type-C switch (like mode-switch). Since the mode-switch will in turn
> have the usb-c-connector (i.e the child of the port driver) as a
> supplier, fw_devlink will not be able to resolve the cyclic dependency
> correctly.
>
> As a result, the mode-switch driver probe() never runs, so mode-switches
> are never registered. Because of that, the port driver probe constantly
> fails with -EPROBE_DEFER, because the Type-C connector class requires all
> switch devices to be registered prior to port registration.
>
> To break this deadlock and allow the mode-switch registration to occur,
> purge all the usb-c-connector nodes' absent suppliers. This eliminates
> the connector as a supplier for a switch and allows it to be probed.
>
> Signed-off-by: Prashant Malani <pmalani@chromium.org>
> Signed-off-by: Pin-yen Lin <treapking@chromium.org>


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

on MT8192 based Hayato (ASUS Chromebook Flip CM3200).