Re: [PATCH] drm/mediatek: ovl_adaptor: balance component registrations

["CK Hu (胡俊光)" <ck.hu@mediatek.com>]

On Wed, 2026-07-22 at 00:22 +0900, Myeonghun Pak wrote:
> External email : Please do not click links or open attachments until you have verified the sender or the content.
> 
> 
> The OVL adaptor registers both an aggregate driver for its child devices
> and a component for the main DRM aggregate. Probe currently ignores an
> error from registering the child aggregate and leaves that aggregate
> registered if registering the DRM component fails. The remove callback
> also leaves the DRM component registered.
> 
> These imbalances can leave component framework entries referring to a
> device whose probe failed or whose driver has been detached. The aggregate
> unbind callback also fails to undo component_bind_all(), leaving its child
> components marked as bound when the aggregate is removed.
> 
> Check the aggregate registration result, unwind it when the component
> registration fails, and unregister the component before the aggregate on
> remove. Keep runtime PM enabled until both framework registrations have
> been removed, and unbind all child components from the aggregate unbind
> callback.

Reviewed-by: CK Hu <ck.hu@mediatek.com>

> 
> Fixes: 453c3364632a ("drm/mediatek: Add ovl_adaptor support for MT8195")
> Cc: stable@vger.kernel.org # 6.4+
> Co-developed-by: Ijae Kim <ae878000@gmail.com>
> Signed-off-by: Ijae Kim <ae878000@gmail.com>
> Signed-off-by: Myeonghun Pak <mhun512@gmail.com>
> ---
>  drivers/gpu/drm/mediatek/mtk_disp_ovl_adaptor.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_disp_ovl_adaptor.c b/drivers/gpu/drm/mediatek/mtk_disp_ovl_adaptor.c
> index c0af3e3b5..6a259872b 100644
> --- a/drivers/gpu/drm/mediatek/mtk_disp_ovl_adaptor.c
> +++ b/drivers/gpu/drm/mediatek/mtk_disp_ovl_adaptor.c
> @@ -625,6 +625,7 @@ static void mtk_disp_ovl_adaptor_master_unbind(struct device *dev)
>         struct mtk_disp_ovl_adaptor *priv = dev_get_drvdata(dev);
> 
>         priv->children_bound = false;
> +       component_unbind_all(dev, priv->mmsys_dev);
>  }
> 
>  static const struct component_master_ops mtk_disp_ovl_adaptor_master_ops = {
> @@ -651,12 +652,15 @@ static int mtk_disp_ovl_adaptor_probe(struct platform_device *pdev)
> 
>         priv->mmsys_dev = pdev->dev.platform_data;
> 
> -       component_master_add_with_match(dev, &mtk_disp_ovl_adaptor_master_ops, match);
> +       ret = component_master_add_with_match(dev, &mtk_disp_ovl_adaptor_master_ops, match);
> +       if (ret)
> +               return dev_err_probe(dev, ret, "Failed to add component master\n");
> 
>         pm_runtime_enable(dev);
> 
>         ret = component_add(dev, &mtk_disp_ovl_adaptor_comp_ops);
>         if (ret != 0) {
> +               component_master_del(dev, &mtk_disp_ovl_adaptor_master_ops);
>                 pm_runtime_disable(dev);
>                 return dev_err_probe(dev, ret, "Failed to add component\n");
>         }
> @@ -666,6 +670,7 @@ static int mtk_disp_ovl_adaptor_probe(struct platform_device *pdev)
> 
>  static void mtk_disp_ovl_adaptor_remove(struct platform_device *pdev)
>  {
> +       component_del(&pdev->dev, &mtk_disp_ovl_adaptor_comp_ops);
>         component_master_del(&pdev->dev, &mtk_disp_ovl_adaptor_master_ops);
>         pm_runtime_disable(&pdev->dev);
>  }
> --
> 2.51.0