Re: [PATCH 04/15] drm/doc: polish for sturct drm_connector

From: Sean Paul <seanpaul@chromium.org>
To: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Daniel Vetter <daniel.vetter@intel.com>,
	DRI Development <dri-devel@lists.freedesktop.org>
Subject: Re: [PATCH 04/15] drm/doc: polish for sturct drm_connector
Date: Thu, 12 Jul 2018 10:01:12 -0400	[thread overview]
Message-ID: <20180712140112.GC20303@art_vandelay> (raw)
In-Reply-To: <20180709084016.23750-5-daniel.vetter@ffwll.ch>

On Mon, Jul 09, 2018 at 10:40:05AM +0200, Daniel Vetter wrote:
> - switch everything over to inline comments
> - add notes about locking, links to functions and other related stuff
> - also include a note about Ville's soon-to-be-merged
>   drm_connector_for_each_possible_encoder().
> 
> Also check that all the hyperlinks in drm_connector.h work and fix
> them as needed.
> 
> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>

Reviewed-by: Sean Paul <seanpaul@chromium.org>

> ---
>  include/drm/drm_connector.h | 191 ++++++++++++++++++++++--------------
>  1 file changed, 120 insertions(+), 71 deletions(-)
> 
> diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
> index 6028638f3108..a0300e3468cb 100644
> --- a/include/drm/drm_connector.h
> +++ b/include/drm/drm_connector.h
> @@ -557,8 +557,7 @@ struct drm_connector_funcs {
>  	 * received for this output connector->edid must be NULL.
>  	 *
>  	 * Drivers using the probe helpers should use
> -	 * drm_helper_probe_single_connector_modes() or
> -	 * drm_helper_probe_single_connector_modes_nomerge() to implement this
> +	 * drm_helper_probe_single_connector_modes() to implement this
>  	 * function.
>  	 *
>  	 * RETURNS:
> @@ -769,45 +768,6 @@ struct drm_cmdline_mode {
>  
>  /**
>   * struct drm_connector - central DRM connector control structure
> - * @dev: parent DRM device
> - * @kdev: kernel device for sysfs attributes
> - * @attr: sysfs attributes
> - * @head: list management
> - * @base: base KMS object
> - * @name: human readable name, can be overwritten by the driver
> - * @connector_type: one of the DRM_MODE_CONNECTOR_<foo> types from drm_mode.h
> - * @connector_type_id: index into connector type enum
> - * @interlace_allowed: can this connector handle interlaced modes?
> - * @doublescan_allowed: can this connector handle doublescan?
> - * @stereo_allowed: can this connector handle stereo modes?
> - * @funcs: connector control functions
> - * @edid_blob_ptr: DRM property containing EDID if present
> - * @properties: property tracking for this connector
> - * @dpms: current dpms state
> - * @helper_private: mid-layer private data
> - * @cmdline_mode: mode line parsed from the kernel cmdline for this connector
> - * @force: a DRM_FORCE_<foo> state for forced mode sets
> - * @override_edid: has the EDID been overwritten through debugfs for testing?
> - * @encoder_ids: valid encoders for this connector
> - * @eld: EDID-like data, if present
> - * @latency_present: AV delay info from ELD, if found
> - * @video_latency: video latency info from ELD, if found
> - * @audio_latency: audio latency info from ELD, if found
> - * @null_edid_counter: track sinks that give us all zeros for the EDID
> - * @bad_edid_counter: track sinks that give us an EDID with invalid checksum
> - * @edid_corrupt: indicates whether the last read EDID was corrupt
> - * @debugfs_entry: debugfs directory for this connector
> - * @has_tile: is this connector connected to a tiled monitor
> - * @tile_group: tile group for the connected monitor
> - * @tile_is_single_monitor: whether the tile is one monitor housing
> - * @num_h_tile: number of horizontal tiles in the tile group
> - * @num_v_tile: number of vertical tiles in the tile group
> - * @tile_h_loc: horizontal location of this tile
> - * @tile_v_loc: vertical location of this tile
> - * @tile_h_size: horizontal size of this tile.
> - * @tile_v_size: vertical size of this tile.
> - * @scaling_mode_property:  Optional atomic property to control the upscaling.
> - * @content_protection_property: Optional property to control content protection
>   *
>   * Each connector may be connected to one or more CRTCs, or may be clonable by
>   * another connector if they can share a CRTC.  Each connector also has a specific
> @@ -815,13 +775,27 @@ struct drm_cmdline_mode {
>   * span multiple monitors).
>   */
>  struct drm_connector {
> +	/** @dev: parent DRM device */
>  	struct drm_device *dev;
> +	/** @kdev: kernel device for sysfs attributes */
>  	struct device *kdev;
> +	/** @attr: sysfs attributes */
>  	struct device_attribute *attr;
> +
> +	/**
> +	 * @head:
> +	 *
> +	 * List of all connectors on a @dev, linked from
> +	 * &drm_mode_config.connector_list. Protected by
> +	 * &drm_mode_config.connector_list_lock, but please only use
> +	 * &drm_connector_list_iter to walk this list.
> +	 */
>  	struct list_head head;
>  
> +	/** @base: base KMS object */
>  	struct drm_mode_object base;
>  
> +	/** @name: human readable name, can be overwritten by the driver */
>  	char *name;
>  
>  	/**
> @@ -839,10 +813,30 @@ struct drm_connector {
>  	 */
>  	unsigned index;
>  
> +	/**
> +	 * @connector_type:
> +	 * one of the DRM_MODE_CONNECTOR_<foo> types from drm_mode.h
> +	 */
>  	int connector_type;
> +	/** @connector_type_id: index into connector type enum */
>  	int connector_type_id;
> +	/**
> +	 * @interlace_allowed:
> +	 * Can this connector handle interlaced modes? Only used by
> +	 * drm_helper_probe_single_connector_modes() for mode filtering.
> +	 */
>  	bool interlace_allowed;
> +	/**
> +	 * @doublescan_allowed:
> +	 * Can this connector handle doublescan? Only used by
> +	 * drm_helper_probe_single_connector_modes() for mode filtering.
> +	 */
>  	bool doublescan_allowed;
> +	/**
> +	 * @stereo_allowed:
> +	 * Can this connector handle stereo modes? Only used by
> +	 * drm_helper_probe_single_connector_modes() for mode filtering.
> +	 */
>  	bool stereo_allowed;
>  
>  	/**
> @@ -891,45 +885,42 @@ struct drm_connector {
>  	 * Protected by &drm_mode_config.mutex.
>  	 */
>  	struct drm_display_info display_info;
> +
> +	/** @funcs: connector control functions */
>  	const struct drm_connector_funcs *funcs;
>  
> +	/**
> +	 * @edid_blob_ptr: DRM property containing EDID if present. Protected by
> +	 * &drm_mode_config.mutex. This should be updated only by calling
> +	 * drm_mode_connector_update_edid_property().
> +	 */
>  	struct drm_property_blob *edid_blob_ptr;
> +
> +	/** @properties: property tracking for this connector */
>  	struct drm_object_properties properties;
>  
> +	/**
> +	 * @scaling_mode_property: Optional atomic property to control the
> +	 * upscaling. See drm_connector_attach_content_protection_property().
> +	 */
>  	struct drm_property *scaling_mode_property;
>  
>  	/**
>  	 * @content_protection_property: DRM ENUM property for content
> -	 * protection
> +	 * protection. See drm_connector_attach_content_protection_property().
>  	 */
>  	struct drm_property *content_protection_property;
>  
>  	/**
>  	 * @path_blob_ptr:
>  	 *
> -	 * DRM blob property data for the DP MST path property.
> +	 * DRM blob property data for the DP MST path property. This should only
> +	 * be updated by calling drm_mode_connector_set_path_property().
>  	 */
>  	struct drm_property_blob *path_blob_ptr;
>  
> -	/**
> -	 * @tile_blob_ptr:
> -	 *
> -	 * DRM blob property data for the tile property (used mostly by DP MST).
> -	 * This is meant for screens which are driven through separate display
> -	 * pipelines represented by &drm_crtc, which might not be running with
> -	 * genlocked clocks. For tiled panels which are genlocked, like
> -	 * dual-link LVDS or dual-link DSI, the driver should try to not expose
> -	 * the tiling and virtualize both &drm_crtc and &drm_plane if needed.
> -	 */
> -	struct drm_property_blob *tile_blob_ptr;
> -
> -/* should we poll this connector for connects and disconnects */
> -/* hot plug detectable */
>  #define DRM_CONNECTOR_POLL_HPD (1 << 0)
> -/* poll for connections */
>  #define DRM_CONNECTOR_POLL_CONNECT (1 << 1)
> -/* can cleanly poll for disconnections without flickering the screen */
> -/* DACs should rarely do this without a lot of testing */
>  #define DRM_CONNECTOR_POLL_DISCONNECT (1 << 2)
>  
>  	/**
> @@ -946,25 +937,40 @@ struct drm_connector {
>  	 *     Periodically poll the connector for connection.
>  	 *
>  	 * DRM_CONNECTOR_POLL_DISCONNECT
> -	 *     Periodically poll the connector for disconnection.
> +	 *     Periodically poll the connector for disconnection, without
> +	 *     causing flickering even when the connector is in use. DACs should
> +	 *     rarely do this without a lot of testing.
>  	 *
>  	 * Set to 0 for connectors that don't support connection status
>  	 * discovery.
>  	 */
>  	uint8_t polled;
>  
> -	/* requested DPMS state */
> +	/**
> +	 * @dpms: Current dpms state. For legacy drivers the
> +	 * &drm_connector_funcs.dpms callback must update this. For atomic
> +	 * drivers, this is handled by the core atomic code, and drivers must
> +	 * only take &drm_crtc_state.active into account.
> +	 */
>  	int dpms;
>  
> +	/** @helper_private: mid-layer private data */
>  	const struct drm_connector_helper_funcs *helper_private;
>  
> -	/* forced on connector */
> +	/** @cmdline_mode: mode line parsed from the kernel cmdline for this connector */
>  	struct drm_cmdline_mode cmdline_mode;
> +	/** @force: a DRM_FORCE_<foo> state for forced mode sets */
>  	enum drm_connector_force force;
> +	/** @override_edid: has the EDID been overwritten through debugfs for testing? */
>  	bool override_edid;
>  
>  #define DRM_CONNECTOR_MAX_ENCODER 3
> +	/**
> +	 * @encoder_ids: Valid encoders for this connector. Please only use
> +	 * drm_connector_for_each_possible_encoder() to enumerate these.
> +	 */
>  	uint32_t encoder_ids[DRM_CONNECTOR_MAX_ENCODER];
> +
>  	/**
>  	 * @encoder: Currently bound encoder driving this connector, if any.
>  	 * Only really meaningful for non-atomic drivers. Atomic drivers should
> @@ -974,19 +980,37 @@ struct drm_connector {
>  	struct drm_encoder *encoder;
>  
>  #define MAX_ELD_BYTES	128
> -	/* EDID bits */
> +	/** @eld: EDID-like data, if present */
>  	uint8_t eld[MAX_ELD_BYTES];
> +	/** @latency_present: AV delay info from ELD, if found */
>  	bool latency_present[2];
> -	int video_latency[2];	/* [0]: progressive, [1]: interlaced */
> +	/**
> +	 * @video_latency: Video latency info from ELD, if found.
> +	 * [0]: progressive, [1]: interlaced
> +	 */
> +	int video_latency[2];
> +	/**
> +	 * @audio_latency: audio latency info from ELD, if found
> +	 * [0]: progressive, [1]: interlaced
> +	 */
>  	int audio_latency[2];
> -	int null_edid_counter; /* needed to workaround some HW bugs where we get all 0s */
> +	/**
> +	 * @null_edid_counter: track sinks that give us all zeros for the EDID.
> +	 * Needed to workaround some HW bugs where we get all 0s
> +	 */
> +	int null_edid_counter;
> +
> +	/** @bad_edid_counter: track sinks that give us an EDID with invalid checksum */
>  	unsigned bad_edid_counter;
>  
> -	/* Flag for raw EDID header corruption - used in Displayport
> -	 * compliance testing - * Displayport Link CTS Core 1.2 rev1.1 4.2.2.6
> +	/**
> +	 * @edid_corrupt: Indicates whether the last read EDID was corrupt. Used
> +	 * in Displayport compliance testing - Displayport Link CTS Core 1.2
> +	 * rev1.1 4.2.2.6
>  	 */
>  	bool edid_corrupt;
>  
> +	/** @debugfs_entry: debugfs directory for this connector */
>  	struct dentry *debugfs_entry;
>  
>  	/**
> @@ -994,7 +1018,7 @@ struct drm_connector {
>  	 *
>  	 * Current atomic state for this connector.
>  	 *
> -	 * This is protected by @drm_mode_config.connection_mutex. Note that
> +	 * This is protected by &drm_mode_config.connection_mutex. Note that
>  	 * nonblocking atomic commits access the current connector state without
>  	 * taking locks. Either by going through the &struct drm_atomic_state
>  	 * pointers, see for_each_oldnew_connector_in_state(),
> @@ -1005,19 +1029,44 @@ struct drm_connector {
>  	 */
>  	struct drm_connector_state *state;
>  
> -	/* DisplayID bits */
> +	/* DisplayID bits. FIXME: Extract into a substruct? */
> +
> +	/**
> +	 * @tile_blob_ptr:
> +	 *
> +	 * DRM blob property data for the tile property (used mostly by DP MST).
> +	 * This is meant for screens which are driven through separate display
> +	 * pipelines represented by &drm_crtc, which might not be running with
> +	 * genlocked clocks. For tiled panels which are genlocked, like
> +	 * dual-link LVDS or dual-link DSI, the driver should try to not expose
> +	 * the tiling and virtualize both &drm_crtc and &drm_plane if needed.
> +	 *
> +	 * This should only be updated by calling
> +	 * drm_mode_connector_set_tile_property().
> +	 */
> +	struct drm_property_blob *tile_blob_ptr;
> +
> +	/** @has_tile: is this connector connected to a tiled monitor */
>  	bool has_tile;
> +	/** @tile_group: tile group for the connected monitor */
>  	struct drm_tile_group *tile_group;
> +	/** @tile_is_single_monitor: whether the tile is one monitor housing */
>  	bool tile_is_single_monitor;
>  
> +	/** @num_h_tile: number of horizontal tiles in the tile group */
> +	/** @num_v_tile: number of vertical tiles in the tile group */
>  	uint8_t num_h_tile, num_v_tile;
> +	/** @tile_h_loc: horizontal location of this tile */
> +	/** @tile_v_loc: vertical location of this tile */
>  	uint8_t tile_h_loc, tile_v_loc;
> +	/** @tile_h_size: horizontal size of this tile. */
> +	/** @tile_v_size: vertical size of this tile. */
>  	uint16_t tile_h_size, tile_v_size;
>  
>  	/**
>  	 * @free_node:
>  	 *
> -	 * List used only by &drm_connector_iter to be able to clean up a
> +	 * List used only by &drm_connector_list_iter to be able to clean up a
>  	 * connector from any context, in conjunction with
>  	 * &drm_mode_config.connector_free_work.
>  	 */
> -- 
> 2.18.0
> 
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-- 
Sean Paul, Software Engineer, Google / Chromium OS
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