linux-kernel - Re: [PATCH] drm/mediatek: mtk_dp: Fix hdmi codec and phy driver unregistration

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Message-ID: <CAGXv+5G8kUg87+JzuCW5sZKHTBA3-CnwSFdrucn_k1rgcpJHOg@mail.gmail.com>
Date: Wed, 9 Apr 2025 14:19:34 +0800
From: Chen-Yu Tsai <wenst@...omium.org>
To: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
Cc: chunkuang.hu@...nel.org, p.zabel@...gutronix.de, airlied@...il.com, 
	simona@...ll.ch, matthias.bgg@...il.com, nancy.lin@...iatek.com, 
	ck.hu@...iatek.com, djkurtz@...omium.org, littlecvr@...omium.org, 
	bibby.hsieh@...iatek.com, dri-devel@...ts.freedesktop.org, 
	linux-mediatek@...ts.infradead.org, linux-kernel@...r.kernel.org, 
	linux-arm-kernel@...ts.infradead.org, kernel@...labora.com
Subject: Re: [PATCH] drm/mediatek: mtk_dp: Fix hdmi codec and phy driver unregistration

On Thu, Apr 3, 2025 at 7:09 PM AngeloGioacchino Del Regno
<angelogioacchino.delregno@...labora.com> wrote:
>
> During probe, this driver is registering two platform devices: one
> for the HDMI Codec driver and one for the DisplayPort PHY driver.
>
> In the probe function, none of the error cases are unregistering
> any of the two platform devices and this may cause registration
> of multiple instances of those in case this driver returns one or
> more probe deferral(s) in the "wrong" spots.
>
> In order to fix this, add devm actions to unregister those and
> remove the manual calls to platform_device_unregister in the
> mtk_dp_remove() function, as those would otherwise be redundant.
>
> Fixes: e71a8ebbe086 ("drm/mediatek: dp: Audio support for MT8195")
> Fixes: caf2ae486742 ("drm/mediatek: dp: Add support for embedded DisplayPort aux-bus")
> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
> ---
>  drivers/gpu/drm/mediatek/mtk_dp.c | 30 ++++++++++++++++++++++++++----
>  1 file changed, 26 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_dp.c b/drivers/gpu/drm/mediatek/mtk_dp.c
> index 3d4648d2e15f..3eb685a46d99 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dp.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dp.c
> @@ -2648,6 +2648,13 @@ static const struct hdmi_codec_ops mtk_dp_audio_codec_ops = {
>         .hook_plugged_cb = mtk_dp_audio_hook_plugged_cb,
>  };
>
> +static void mtk_dp_unregister_pdevs(void *data)
> +{
> +       struct platform_device *ext_pdev = data;
> +
> +       platform_device_unregister(ext_pdev);
> +}
> +
>  static int mtk_dp_register_audio_driver(struct device *dev)
>  {
>         struct mtk_dp *mtk_dp = dev_get_drvdata(dev);
> @@ -2658,18 +2665,29 @@ static int mtk_dp_register_audio_driver(struct device *dev)
>                 .data = mtk_dp,
>                 .no_capture_mute = 1,
>         };
> +       int ret;
>
>         mtk_dp->audio_pdev = platform_device_register_data(dev,
>                                                            HDMI_CODEC_DRV_NAME,
>                                                            PLATFORM_DEVID_AUTO,
>                                                            &codec_data,
>                                                            sizeof(codec_data));
> -       return PTR_ERR_OR_ZERO(mtk_dp->audio_pdev);
> +       if (IS_ERR(mtk_dp->audio_pdev))
> +               return PTR_ERR(mtk_dp->audio_pdev);
> +
> +       ret = devm_add_action_or_reset(dev, mtk_dp_unregister_pdevs, mtk_dp->phy_dev);

Wrong platform device given here. You want audio_pdev instead.


Having briefly looked at this driver, I think it needs more cleanup. :o


ChenYu

> +       if (ret) {
> +               platform_device_unregister(mtk_dp->audio_pdev);
> +               return dev_err_probe(dev, ret,
> +                                    "Failed to add codec unregister devm action");
> +       }
> +       return 0;
>  }
>
>  static int mtk_dp_register_phy(struct mtk_dp *mtk_dp)
>  {
>         struct device *dev = mtk_dp->dev;
> +       int ret;
>
>         mtk_dp->phy_dev = platform_device_register_data(dev, "mediatek-dp-phy",
>                                                         PLATFORM_DEVID_AUTO,
> @@ -2679,6 +2697,13 @@ static int mtk_dp_register_phy(struct mtk_dp *mtk_dp)
>                 return dev_err_probe(dev, PTR_ERR(mtk_dp->phy_dev),
>                                      "Failed to create device mediatek-dp-phy\n");
>
> +       ret = devm_add_action_or_reset(dev, mtk_dp_unregister_pdevs, mtk_dp->phy_dev);
> +       if (ret) {
> +               platform_device_unregister(mtk_dp->phy_dev);
> +               return dev_err_probe(dev, ret,
> +                                    "Failed to add phy unregister devm action");
> +       }
> +
>         mtk_dp_get_calibration_data(mtk_dp);
>
>         mtk_dp->phy = devm_phy_get(&mtk_dp->phy_dev->dev, "dp");
> @@ -2848,9 +2873,6 @@ static void mtk_dp_remove(struct platform_device *pdev)
>         pm_runtime_disable(&pdev->dev);
>         if (mtk_dp->data->bridge_type != DRM_MODE_CONNECTOR_eDP)
>                 del_timer_sync(&mtk_dp->debounce_timer);
> -       platform_device_unregister(mtk_dp->phy_dev);
> -       if (mtk_dp->audio_pdev)
> -               platform_device_unregister(mtk_dp->audio_pdev);
>  }
>
>  #ifdef CONFIG_PM_SLEEP
> --
> 2.48.1
>