@@ -655,7 +655,6 @@ struct drm_cmdline_mode {
* @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
- * @state: current atomic state 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
@@ -823,6 +822,21 @@ struct drm_connector {
struct dentry *debugfs_entry;
+ /**
+ * @state:
+ *
+ * Current atomic state for this connector.
+ *
+ * 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_connector_in_state(),
+ * for_each_oldnew_connector_in_state(),
+ * for_each_old_connector_in_state() and
+ * for_each_new_connector_in_state(). Or through careful ordering of
+ * atomic commit operations as implemented in the atomic helpers, see
+ * &struct drm_crtc_commit.
+ */
struct drm_connector_state *state;
/* DisplayID bits */
@@ -702,10 +702,12 @@ struct drm_crtc {
/**
* @mutex:
*
- * This provides a read lock for the overall crtc state (mode, dpms
+ * This provides a read lock for the overall CRTC state (mode, dpms
* state, ...) and a write lock for everything which can be update
- * without a full modeset (fb, cursor data, crtc properties ...). A full
+ * without a full modeset (fb, cursor data, CRTC properties ...). A full
* modeset also need to grab &drm_mode_config.connection_mutex.
+ *
+ * For atomic drivers specifically this protects @state.
*/
struct drm_modeset_lock mutex;
@@ -751,6 +753,14 @@ struct drm_crtc {
* @state:
*
* Current atomic state for this CRTC.
+ *
+ * This is protected by @mutex. Note that nonblocking atomic commits
+ * access the current CRTC state without taking locks. Either by going
+ * through the &struct drm_atomic_state pointers, see
+ * for_each_crtc_in_state(), for_each_oldnew_crtc_in_state(),
+ * for_each_old_crtc_in_state() and for_each_new_crtc_in_state(). Or
+ * through careful ordering of atomic commit operations as implemented
+ * in the atomic helpers, see &struct drm_crtc_commit.
*/
struct drm_crtc_state *state;
@@ -307,21 +307,6 @@ struct drm_mode_config_funcs {
/**
* struct drm_mode_config - Mode configuration control structure
- * @mutex: mutex protecting KMS related lists and structures
- * @connection_mutex: ww mutex protecting connector state and routing
- * @acquire_ctx: global implicit acquire context used by atomic drivers for
- * legacy IOCTLs
- * @fb_lock: mutex to protect fb state and lists
- * @num_fb: number of fbs available
- * @fb_list: list of framebuffers available
- * @num_encoder: number of encoders on this device
- * @encoder_list: list of encoder objects
- * @num_overlay_plane: number of overlay planes on this device
- * @num_total_plane: number of universal (i.e. with primary/curso) planes on this device
- * @plane_list: list of plane objects
- * @num_crtc: number of CRTCs on this device
- * @crtc_list: list of CRTC objects
- * @property_list: list of property objects
* @min_width: minimum pixel width on this device
* @min_height: minimum pixel height on this device
* @max_width: maximum pixel width on this device
@@ -332,9 +317,6 @@ struct drm_mode_config_funcs {
* @poll_running: track polling status for this device
* @delayed_event: track delayed poll uevent deliver for this device
* @output_poll_work: delayed work for polling in process context
- * @property_blob_list: list of all the blob property objects
- * @blob_lock: mutex for blob property allocation and management
- * @*_property: core property tracking
* @preferred_depth: preferred RBG pixel depth, used by fb helpers
* @prefer_shadow: hint to userspace to prefer shadow-fb rendering
* @cursor_width: hint to userspace for max cursor width
@@ -346,9 +328,37 @@ struct drm_mode_config_funcs {
* global restrictions are also here, e.g. dimension restrictions.
*/
struct drm_mode_config {
- struct mutex mutex; /* protects configuration (mode lists etc.) */
- struct drm_modeset_lock connection_mutex; /* protects connector->encoder and encoder->crtc links */
- struct drm_modeset_acquire_ctx *acquire_ctx; /* for legacy _lock_all() / _unlock_all() */
+ /**
+ * @mutex:
+ *
+ * This is the big scary modeset BKL which protects everything that
+ * isn't protect otherwise. Scope is unclear and fuzzy, try to remove
+ * anything from under it's protection and move it into more well-scoped
+ * locks.
+ *
+ * The one important thing this protects is the use of @acquire_ctx.
+ */
+ struct mutex mutex;
+
+ /**
+ * @connection_mutex:
+ *
+ * This protects connector state and the connector to encoder to CRTC
+ * routing chain.
+ *
+ * For atomic drivers specifically this protects &drm_connector.state.
+ */
+ struct drm_modeset_lock connection_mutex;
+
+ /**
+ * @acquire_ctx:
+ *
+ * Global implicit acquire context used by atomic drivers for legacy
+ * IOCTLs. Deprecated, since implicit locking contexts make it
+ * impossible to use driver-private &struct drm_modeset_lock. Users of
+ * this must hold @mutex.
+ */
+ struct drm_modeset_acquire_ctx *acquire_ctx;
/**
* @idr_mutex:
@@ -374,8 +384,11 @@ struct drm_mode_config {
*/
struct idr tile_idr;
- struct mutex fb_lock; /* proctects global and per-file fb lists */
+ /** @fb_lock: Mutex to protect fb the global @fb_list and @num_fb. */
+ struct mutex fb_lock;
+ /** @num_fb: Number of entries on @fb_list. */
int num_fb;
+ /** @fb_list: List of all &struct drm_framebuffer. */
struct list_head fb_list;
/**
@@ -393,27 +406,80 @@ struct drm_mode_config {
*/
struct ida connector_ida;
/**
- * @connector_list: List of connector objects. Protected by
- * @connector_list_lock. Only use drm_for_each_connector_iter() and
+ * @connector_list:
+ *
+ * List of connector objects linked with &drm_connector.head. Protected
+ * by @connector_list_lock. Only use drm_for_each_connector_iter() and
* &struct drm_connector_list_iter to walk this list.
*/
struct list_head connector_list;
+ /**
+ * @num_encoder:
+ *
+ * Number of encoders on this device. This is invariant over the
+ * lifetime of a device and hence doesn't need any locks.
+ */
int num_encoder;
+ /**
+ * @encoder_list:
+ *
+ * List of encoder objects linked with &drm_encoder.head. This is
+ * invariant over the lifetime of a device and hence doesn't need any
+ * locks.
+ */
struct list_head encoder_list;
- /*
- * Track # of overlay planes separately from # of total planes. By
- * default we only advertise overlay planes to userspace; if userspace
- * sets the "universal plane" capability bit, we'll go ahead and
- * expose all planes.
+ /**
+ * @num_overlay_plane:
+ *
+ * Number of overlay planes on this device, excluding primary and cursor
+ * planes.
+ *
+ * Track number of overlay planes separately from number of total
+ * planes. By default we only advertise overlay planes to userspace; if
+ * userspace sets the "universal plane" capability bit, we'll go ahead
+ * and expose all planes. This is invariant over the lifetime of a
+ * device and hence doesn't need any locks.
*/
int num_overlay_plane;
+ /**
+ * @num_total_plane:
+ *
+ * Number of universal (i.e. with primary/curso) planes on this device.
+ * This is invariant over the lifetime of a device and hence doesn't
+ * need any locks.
+ */
int num_total_plane;
+ /**
+ * @plane_list:
+ *
+ * List of plane objects linked with &drm_plane.head. This is invariant
+ * over the lifetime of a device and hence doesn't need any locks.
+ */
struct list_head plane_list;
+ /**
+ * @num_crtc:
+ *
+ * Number of CRTCs on this device linked with &drm_crtc.head. This is invariant over the lifetime
+ * of a device and hence doesn't need any locks.
+ */
int num_crtc;
+ /**
+ * @crtc_list:
+ *
+ * List of CRTC objects linked with &drm_crtc.head. This is invariant
+ * over the lifetime of a device and hence doesn't need any locks.
+ */
struct list_head crtc_list;
+ /**
+ * @property_list:
+ *
+ * List of property type objects linked with &drm_property.head. This is
+ * invariant over the lifetime of a device and hence doesn't need any
+ * locks.
+ */
struct list_head property_list;
int min_width, min_height;
@@ -427,10 +493,24 @@ struct drm_mode_config {
bool delayed_event;
struct delayed_work output_poll_work;
+ /**
+ * @blob_lock:
+ *
+ * Mutex for blob property allocation and management, protects
+ * @property_blob_list and &drm_file.blobs.
+ */
struct mutex blob_lock;
- /* pointers to standard properties */
+ /**
+ * @property_blob_list:
+ *
+ * List of all the blob property objects linked with
+ * &drm_property_blob.head. Protected by @blob_lock.
+ */
struct list_head property_blob_list;
+
+ /* pointers to standard properties */
+
/**
* @edid_property: Default connector property to hold the EDID of the
* currently connected sink, if any.
@@ -459,7 +459,6 @@ enum drm_plane_type {
* @funcs: helper functions
* @properties: property tracking for this plane
* @type: type of plane (overlay, primary, cursor)
- * @state: current atomic state for this plane
* @zpos_property: zpos property for this plane
* @rotation_property: rotation property for this plane
* @helper_private: mid-layer private data
@@ -476,6 +475,8 @@ struct drm_plane {
* Protects modeset plane state, together with the &drm_crtc.mutex of
* CRTC this plane is linked to (when active, getting activated or
* getting disabled).
+ *
+ * For atomic drivers specifically this protects @state.
*/
struct drm_modeset_lock mutex;
@@ -505,6 +506,19 @@ struct drm_plane {
const struct drm_plane_helper_funcs *helper_private;
+ /**
+ * @state:
+ *
+ * Current atomic state for this plane.
+ *
+ * This is protected by @mutex. Note that nonblocking atomic commits
+ * access the current plane state without taking locks. Either by going
+ * through the &struct drm_atomic_state pointers, see
+ * for_each_plane_in_state(), for_each_oldnew_plane_in_state(),
+ * for_each_old_plane_in_state() and for_each_new_plane_in_state(). Or
+ * through careful ordering of atomic commit operations as implemented
+ * in the atomic helpers, see &struct drm_crtc_commit.
+ */
struct drm_plane_state *state;
struct drm_property *zpos_property;