[PATCH 03/14] drm/bridge: analogix_dp: register AUX bus after enabling runtime PM

[Robert Foss]

On Fri, May 3, 2024 at 5:12 PM Lucas Stach <l.stach at pengutronix.de> wrote:
>
> AUX transactions require the controller to be in working state and
> take a runtime PM reference. To avoid potential races beween the
> first transactions on the bus and runtime PM being set up, move the
> AUX registration behind the runtime PM setup.
>
> Signed-off-by: Lucas Stach <l.stach at pengutronix.de>
> ---
>  .../drm/bridge/analogix/analogix_dp_core.c    | 19 +++++++++++--------
>  1 file changed, 11 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> index b39721588980..0af2a70ae5bf 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> @@ -1728,31 +1728,34 @@ int analogix_dp_bind(struct analogix_dp_device *dp, struct drm_device *drm_dev)
>         dp->drm_dev = drm_dev;
>         dp->encoder = dp->plat_data->encoder;
>
> +       pm_runtime_use_autosuspend(dp->dev);
> +       pm_runtime_set_autosuspend_delay(dp->dev, 100);
> +       pm_runtime_enable(dp->dev);
> +
>         dp->aux.name = "DP-AUX";
>         dp->aux.transfer = analogix_dpaux_transfer;
>         dp->aux.dev = dp->dev;
>         dp->aux.drm_dev = drm_dev;
>
>         ret = drm_dp_aux_register(&dp->aux);
> -       if (ret)
> -               return ret;
> -
> -       pm_runtime_use_autosuspend(dp->dev);
> -       pm_runtime_set_autosuspend_delay(dp->dev, 100);
> -       pm_runtime_enable(dp->dev);
> +       if (ret) {
> +               DRM_ERROR("failed to register AUX (%d)\n", ret);
> +               goto err_disable_pm_runtime;
> +       }
>
>         ret = analogix_dp_create_bridge(drm_dev, dp);
>         if (ret) {
>                 DRM_ERROR("failed to create bridge (%d)\n", ret);
> -               goto err_disable_pm_runtime;
> +               goto err_unregister_aux;
>         }
>
>         return 0;
>
> +err_unregister_aux:
> +       drm_dp_aux_unregister(&dp->aux);
>  err_disable_pm_runtime:
>         pm_runtime_dont_use_autosuspend(dp->dev);
>         pm_runtime_disable(dp->dev);
> -       drm_dp_aux_unregister(&dp->aux);
>
>         return ret;
>  }
> --
> 2.39.2
>

Reviewed-by: Robert Foss <rfoss at kernel.org>