[PATCH] drm: clean cached display info

[Daniel Vetter]

On Thu, Dec 29, 2016 at 05:58:50PM +0530, Shashank Sharma wrote:
> This patch adds a small helper function, which clears the cached
> information about a hot-pluggable display, from connector. On event
> This will run on event of a hot-unplug, keeping the connector's display
> info up-to-date, avoiding any errors due to invalid cached data.
> 
> Forking this patch out from the 3 patch series:
> 	https://patchwork.freedesktop.org/patch/128961/
> (still under review) and sending as individual patch.
> 
> Cc: Jose Abreu <joabreu at synopsys.com>
> Cc: Daniel Vetter <daniel at ffwll.ch>
> 
> Suggested-by: Jose Abreu <joabreu at synopsys.com>
> Signed-off-by: Shashank Sharma <shashank.sharma at intel.com>
> ---
>  drivers/gpu/drm/drm_probe_helper.c | 22 ++++++++++++++++++++++
>  1 file changed, 22 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c
> index 7cff91e..65a6a1f 100644
> --- a/drivers/gpu/drm/drm_probe_helper.c
> +++ b/drivers/gpu/drm/drm_probe_helper.c
> @@ -164,6 +164,18 @@ void drm_kms_helper_poll_enable_locked(struct drm_device *dev)
>  }
>  
>  /**
> + * drm_helper_clear_display_info - clean cached display information for
> + * hot pluggable displays, on event of hot-unplug
> + * @connector: connector under event
> + */
> +void drm_helper_clear_display_info(struct drm_connector *connector)
> +{
> +	struct drm_display_info *info = &connector->display_info;
> +
> +	memset(info, 0, sizeof(*info));
> +}
> +
> +/**
>   * drm_helper_probe_single_connector_modes - get complete set of display modes
>   * @connector: connector to probe
>   * @maxX: max width for modes
> @@ -288,6 +300,16 @@ int drm_helper_probe_single_connector_modes(struct drm_connector *connector,
>  		DRM_DEBUG_KMS("[CONNECTOR:%d:%s] disconnected\n",
>  			connector->base.id, connector->name);
>  		drm_mode_connector_update_edid_property(connector, NULL);
> +
> +		/*
> +		 * Connector status change to disconnected, time to clean
> +		 * cached display information.
> +		 * Any driver which doesn't use this probe_helper function
> +		 * should implement update of EDID property and display_info
> +		 * on its own.
> +		 */
> +		drm_helper_clear_display_info(connector);

This isn't really the only place where you can switch to disconnected. I
think something along the lines of some of Jani's recent RFC where we try
to make this functions dtrt thing for a NULL edid would be much more
robust.
-Daniel

> +
>  		verbose_prune = false;
>  		goto prune;
>  	}
> -- 
> 1.9.1
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch