/* * Copyright © 2006 Keith Packard * Copyright © 2007-2008 Dave Airlie * Copyright © 2007-2008 Intel Corporation * Jesse Barnes <jesse.barnes@intel.com> * * Permission is hereby granted, free of charge, to any person obtaining a * copy of this software and associated documentation files (the "Software"), * to deal in the Software without restriction, including without limitation * the rights to use, copy, modify, merge, publish, distribute, sublicense, * and/or sell copies of the Software, and to permit persons to whom the * Software is furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR * OTHER DEALINGS IN THE SOFTWARE. */ #ifndef __DRM_CRTC_H__ #define __DRM_CRTC_H__ #include <linux/i2c.h> #include <linux/spinlock.h> #include <linux/types.h> #include <linux/fb.h> #include <linux/hdmi.h> #include <linux/media-bus-format.h> #include <uapi/drm/drm_mode.h> #include <uapi/drm/drm_fourcc.h> #include <drm/drm_modeset_lock.h> #include <drm/drm_rect.h> #include <drm/drm_mode_object.h> #include <drm/drm_framebuffer.h> #include <drm/drm_modes.h> #include <drm/drm_connector.h> #include <drm/drm_encoder.h> #include <drm/drm_property.h> #include <drm/drm_bridge.h> #include <drm/drm_edid.h> #include <drm/drm_plane.h> #include <drm/drm_blend.h> #include <drm/drm_color_mgmt.h> #include <drm/drm_debugfs_crc.h> #include <drm/drm_mode_config.h> struct drm_device; struct drm_mode_set; struct drm_file; struct drm_clip_rect; struct drm_printer; struct device_node; struct dma_fence; struct edid; static inline int64_t U642I64(uint64_t val) { return (int64_t)*((int64_t *)&val); } static inline uint64_t I642U64(int64_t val) { return (uint64_t)*((uint64_t *)&val); } struct drm_crtc; struct drm_encoder; struct drm_pending_vblank_event; struct drm_plane; struct drm_bridge; struct drm_atomic_state; struct drm_crtc_helper_funcs; struct drm_encoder_helper_funcs; struct drm_plane_helper_funcs; /** * struct drm_crtc_state - mutable CRTC state * @crtc: backpointer to the CRTC * @enable: whether the CRTC should be enabled, gates all other state * @active: whether the CRTC is actively displaying (used for DPMS) * @planes_changed: planes on this crtc are updated * @mode_changed: crtc_state->mode or crtc_state->enable has been changed * @active_changed: crtc_state->active has been toggled. * @connectors_changed: connectors to this crtc have been updated * @zpos_changed: zpos values of planes on this crtc have been updated * @color_mgmt_changed: color management properties have changed (degamma or * gamma LUT or CSC matrix) * @plane_mask: bitmask of (1 << drm_plane_index(plane)) of attached planes * @connector_mask: bitmask of (1 << drm_connector_index(connector)) of attached connectors * @encoder_mask: bitmask of (1 << drm_encoder_index(encoder)) of attached encoders * @last_vblank_count: for helpers and drivers to capture the vblank of the * update to ensure framebuffer cleanup isn't done too early * @adjusted_mode: for use by helpers and drivers to compute adjusted mode timings * @mode: current mode timings * @mode_blob: &drm_property_blob for @mode * @degamma_lut: Lookup table for converting framebuffer pixel data * before apply the conversion matrix * @ctm: Transformation matrix * @gamma_lut: Lookup table for converting pixel data after the * conversion matrix * @state: backpointer to global drm_atomic_state * * Note that the distinction between @enable and @active is rather subtile: * Flipping @active while @enable is set without changing anything else may * never return in a failure from the ->atomic_check callback. Userspace assumes * that a DPMS On will always succeed. In other words: @enable controls resource * assignment, @active controls the actual hardware state. * * The three booleans active_changed, connectors_changed and mode_changed are * intended to indicate whether a full modeset is needed, rather than strictly * describing what has changed in a commit. * See also: drm_atomic_crtc_needs_modeset() */ struct drm_crtc_state { struct drm_crtc *crtc; bool enable; bool active; /* computed state bits used by helpers and drivers */ bool planes_changed : 1; bool mode_changed : 1; bool active_changed : 1; bool connectors_changed : 1; bool zpos_changed : 1; bool color_mgmt_changed : 1; /* attached planes bitmask: * WARNING: transitional helpers do not maintain plane_mask so * drivers not converted over to atomic helpers should not rely * on plane_mask being accurate! */ u32 plane_mask; u32 connector_mask; u32 encoder_mask; /* last_vblank_count: for vblank waits before cleanup */ u32 last_vblank_count; /* adjusted_mode: for use by helpers and drivers */ struct drm_display_mode adjusted_mode; struct drm_display_mode mode; /* blob property to expose current mode to atomic userspace */ struct drm_property_blob *mode_blob; /* blob property to expose color management to userspace */ struct drm_property_blob *degamma_lut; struct drm_property_blob *ctm; struct drm_property_blob *gamma_lut; /** * @event: * * Optional pointer to a DRM event to signal upon completion of the * state update. The driver must send out the event when the atomic * commit operation completes. There are two cases: * * - The event is for a CRTC which is being disabled through this * atomic commit. In that case the event can be send out any time * after the hardware has stopped scanning out the current * framebuffers. It should contain the timestamp and counter for the * last vblank before the display pipeline was shut off. * * - For a CRTC which is enabled at the end of the commit (even when it * undergoes an full modeset) the vblank timestamp and counter must * be for the vblank right before the first frame that scans out the * new set of buffers. Again the event can only be sent out after the * hardware has stopped scanning out the old buffers. * * - Events for disabled CRTCs are not allowed, and drivers can ignore * that case. * * This can be handled by the drm_crtc_send_vblank_event() function, * which the driver should call on the provided event upon completion of * the atomic commit. Note that if the driver supports vblank signalling * and timestamping the vblank counters and timestamps must agree with * the ones returned from page flip events. With the current vblank * helper infrastructure this can be achieved by holding a vblank * reference while the page flip is pending, acquired through * drm_crtc_vblank_get() and released with drm_crtc_vblank_put(). * Drivers are free to implement their own vblank counter and timestamp * tracking though, e.g. if they have accurate timestamp registers in * hardware. * * For hardware which supports some means to synchronize vblank * interrupt delivery with committing display state there's also * drm_crtc_arm_vblank_event(). See the documentation of that function * for a detailed discussion of the constraints it needs to be used * safely. */ struct drm_pending_vblank_event *event; struct drm_atomic_state *state; }; /** * struct drm_crtc_funcs - control CRTCs for a given device * * The drm_crtc_funcs structure is the central CRTC management structure * in the DRM. Each CRTC controls one or more connectors (note that the name * CRTC is simply historical, a CRTC may control LVDS, VGA, DVI, TV out, etc. * connectors, not just CRTs). * * Each driver is responsible for filling out this structure at startup time, * in addition to providing other modesetting features, like i2c and DDC * bus accessors. */ struct drm_crtc_funcs { /** * @reset: * * Reset CRTC hardware and software state to off. This function isn't * called by the core directly, only through drm_mode_config_reset(). * It's not a helper hook only for historical reasons. * * Atomic drivers can use drm_atomic_helper_crtc_reset() to reset * atomic state using this hook. */ void (*reset)(struct drm_crtc *crtc); /** * @cursor_set: * * Update the cursor image. The cursor position is relative to the CRTC * and can be partially or fully outside of the visible area. * * Note that contrary to all other KMS functions the legacy cursor entry * points don't take a framebuffer object, but instead take directly a * raw buffer object id from the driver's buffer manager (which is * either GEM or TTM for current drivers). * * This entry point is deprecated, drivers should instead implement * universal plane support and register a proper cursor plane using * drm_crtc_init_with_planes(). * * This callback is optional * * RETURNS: * * 0 on success or a negative error code on failure. */ int (*cursor_set)(struct drm_crtc *crtc, struct drm_file *file_priv, uint32_t handle, uint32_t width, uint32_t height); /** * @cursor_set2: * * Update the cursor image, including hotspot information. The hotspot * must not affect the cursor position in CRTC coordinates, but is only * meant as a hint for virtualized display hardware to coordinate the * guests and hosts cursor position. The cursor hotspot is relative to * the cursor image. Otherwise this works exactly like @cursor_set. * * This entry point is deprecated, drivers should instead implement * universal plane support and register a proper cursor plane using * drm_crtc_init_with_planes(). * * This callback is optional. * * RETURNS: * * 0 on success or a negative error code on failure. */ int (*cursor_set2)(struct drm_crtc *crtc, struct drm_file *file_priv, uint32_t handle, uint32_t width, uint32_t height, int32_t hot_x, int32_t hot_y); /** * @cursor_move: * * Update the cursor position. The cursor does not need to be visible * when this hook is called. * * This entry point is deprecated, drivers should instead implement * universal plane support and register a proper cursor plane using * drm_crtc_init_with_planes(). * * This callback is optional. * * RETURNS: * * 0 on success or a negative error code on failure. */ int (*cursor_move)(struct drm_crtc *crtc, int x, int y); /** * @gamma_set: * * Set gamma on the CRTC. * * This callback is optional. * * NOTE: * * Drivers that support gamma tables and also fbdev emulation through * the provided helper library need to take care to fill out the gamma * hooks for both. Currently there's a bit an unfortunate duplication * going on, which should eventually be unified to just one set of * hooks. */ int (*gamma_set)(struct drm_crtc *crtc, u16 *r, u16 *g, u16 *b, uint32_t size); /** * @destroy: * * Clean up plane resources. This is only called at driver unload time * through drm_mode_config_cleanup() since a CRTC cannot be hotplugged * in DRM. */ void (*destroy)(struct drm_crtc *crtc); /** * @set_config: * * This is the main legacy entry point to change the modeset state on a * CRTC. All the details of the desired configuration are passed in a * struct &drm_mode_set - see there for details. * * Drivers implementing atomic modeset should use * drm_atomic_helper_set_config() to implement this hook. * * RETURNS: * * 0 on success or a negative error code on failure. */ int (*set_config)(struct drm_mode_set *set); /** * @page_flip: * * Legacy entry point to schedule a flip to the given framebuffer. * * Page flipping is a synchronization mechanism that replaces the frame * buffer being scanned out by the CRTC with a new frame buffer during * vertical blanking, avoiding tearing (except when requested otherwise * through the DRM_MODE_PAGE_FLIP_ASYNC flag). When an application * requests a page flip the DRM core verifies that the new frame buffer * is large enough to be scanned out by the CRTC in the currently * configured mode and then calls the CRTC ->page_flip() operation with a * pointer to the new frame buffer. * * The driver must wait for any pending rendering to the new framebuffer * to complete before executing the flip. It should also wait for any * pending rendering from other drivers if the underlying buffer is a * shared dma-buf. * * An application can request to be notified when the page flip has * completed. The drm core will supply a struct &drm_event in the event * parameter in this case. This can be handled by the * drm_crtc_send_vblank_event() function, which the driver should call on * the provided event upon completion of the flip. Note that if * the driver supports vblank signalling and timestamping the vblank * counters and timestamps must agree with the ones returned from page * flip events. With the current vblank helper infrastructure this can * be achieved by holding a vblank reference while the page flip is * pending, acquired through drm_crtc_vblank_get() and released with * drm_crtc_vblank_put(). Drivers are free to implement their own vblank * counter and timestamp tracking though, e.g. if they have accurate * timestamp registers in hardware. * * This callback is optional. * * NOTE: * * Very early versions of the KMS ABI mandated that the driver must * block (but not reject) any rendering to the old framebuffer until the * flip operation has completed and the old framebuffer is no longer * visible. This requirement has been lifted, and userspace is instead * expected to request delivery of an event and wait with recycling old * buffers until such has been received. * * RETURNS: * * 0 on success or a negative error code on failure. Note that if a * ->page_flip() operation is already pending the callback should return * -EBUSY. Pageflips on a disabled CRTC (either by setting a NULL mode * or just runtime disabled through DPMS respectively the new atomic * "ACTIVE" state) should result in an -EINVAL error code. Note that * drm_atomic_helper_page_flip() checks this already for atomic drivers. */ int (*page_flip)(struct drm_crtc *crtc, struct drm_framebuffer *fb, struct drm_pending_vblank_event *event, uint32_t flags); /** * @page_flip_target: * * Same as @page_flip but with an additional parameter specifying the * absolute target vertical blank period (as reported by * drm_crtc_vblank_count()) when the flip should take effect. * * Note that the core code calls drm_crtc_vblank_get before this entry * point, and will call drm_crtc_vblank_put if this entry point returns * any non-0 error code. It's the driver's responsibility to call * drm_crtc_vblank_put after this entry point returns 0, typically when * the flip completes. */ int (*page_flip_target)(struct drm_crtc *crtc, struct drm_framebuffer *fb, struct drm_pending_vblank_event *event, uint32_t flags, uint32_t target); /** * @set_property: * * This is the legacy entry point to update a property attached to the * CRTC. * * Drivers implementing atomic modeset should use * drm_atomic_helper_crtc_set_property() to implement this hook. * * This callback is optional if the driver does not support any legacy * driver-private properties. * * RETURNS: * * 0 on success or a negative error code on failure. */ int (*set_property)(struct drm_crtc *crtc, struct drm_property *property, uint64_t val); /** * @atomic_duplicate_state: * * Duplicate the current atomic state for this CRTC and return it. * The core and helpers gurantee that any atomic state duplicated with * this hook and still owned by the caller (i.e. not transferred to the * driver by calling ->atomic_commit() from struct * &drm_mode_config_funcs) will be cleaned up by calling the * @atomic_destroy_state hook in this structure. * * Atomic drivers which don't subclass struct &drm_crtc should use * drm_atomic_helper_crtc_duplicate_state(). Drivers that subclass the * state structure to extend it with driver-private state should use * __drm_atomic_helper_crtc_duplicate_state() to make sure shared state is * duplicated in a consistent fashion across drivers. * * It is an error to call this hook before crtc->state has been * initialized correctly. * * NOTE: * * If the duplicate state references refcounted resources this hook must * acquire a reference for each of them. The driver must release these * references again in @atomic_destroy_state. * * RETURNS: * * Duplicated atomic state or NULL when the allocation failed. */ struct drm_crtc_state *(*atomic_duplicate_state)(struct drm_crtc *crtc); /** * @atomic_destroy_state: * * Destroy a state duplicated with @atomic_duplicate_state and release * or unreference all resources it references */ void (*atomic_destroy_state)(struct drm_crtc *crtc, struct drm_crtc_state *state); /** * @atomic_set_property: * * Decode a driver-private property value and store the decoded value * into the passed-in state structure. Since the atomic core decodes all * standardized properties (even for extensions beyond the core set of * properties which might not be implemented by all drivers) this * requires drivers to subclass the state structure. * * Such driver-private properties should really only be implemented for * truly hardware/vendor specific state. Instead it is preferred to * standardize atomic extension and decode the properties used to expose * such an extension in the core. * * Do not call this function directly, use * drm_atomic_crtc_set_property() instead. * * This callback is optional if the driver does not support any * driver-private atomic properties. * * NOTE: * * This function is called in the state assembly phase of atomic * modesets, which can be aborted for any reason (including on * userspace's request to just check whether a configuration would be * possible). Drivers MUST NOT touch any persistent state (hardware or * software) or data structures except the passed in @state parameter. * * Also since userspace controls in which order properties are set this * function must not do any input validation (since the state update is * incomplete and hence likely inconsistent). Instead any such input * validation must be done in the various atomic_check callbacks. * * RETURNS: * * 0 if the property has been found, -EINVAL if the property isn't * implemented by the driver (which should never happen, the core only * asks for properties attached to this CRTC). No other validation is * allowed by the driver. The core already checks that the property * value is within the range (integer, valid enum value, ...) the driver * set when registering the property. */ int (*atomic_set_property)(struct drm_crtc *crtc, struct drm_crtc_state *state, struct drm_property *property, uint64_t val); /** * @atomic_get_property: * * Reads out the decoded driver-private property. This is used to * implement the GETCRTC IOCTL. * * Do not call this function directly, use * drm_atomic_crtc_get_property() instead. * * This callback is optional if the driver does not support any * driver-private atomic properties. * * RETURNS: * * 0 on success, -EINVAL if the property isn't implemented by the * driver (which should never happen, the core only asks for * properties attached to this CRTC). */ int (*atomic_get_property)(struct drm_crtc *crtc, const struct drm_crtc_state *state, struct drm_property *property, uint64_t *val); /** * @late_register: * * This optional hook can be used to register additional userspace * interfaces attached to the crtc like debugfs interfaces. * It is called late in the driver load sequence from drm_dev_register(). * Everything added from this callback should be unregistered in * the early_unregister callback. * * Returns: * * 0 on success, or a negative error code on failure. */ int (*late_register)(struct drm_crtc *crtc); /** * @early_unregister: * * This optional hook should be used to unregister the additional * userspace interfaces attached to the crtc from * late_unregister(). It is called from drm_dev_unregister(), * early in the driver unload sequence to disable userspace access * before data structures are torndown. */ void (*early_unregister)(struct drm_crtc *crtc); /** * @set_crc_source: * * Changes the source of CRC checksums of frames at the request of * userspace, typically for testing purposes. The sources available are * specific of each driver and a %NULL value indicates that CRC * generation is to be switched off. * * When CRC generation is enabled, the driver should call * drm_crtc_add_crc_entry() at each frame, providing any information * that characterizes the frame contents in the crcN arguments, as * provided from the configured source. Drivers must accept a "auto" * source name that will select a default source for this CRTC. * * This callback is optional if the driver does not support any CRC * generation functionality. * * RETURNS: * * 0 on success or a negative error code on failure. */ int (*set_crc_source)(struct drm_crtc *crtc, const char *source, size_t *values_cnt); /** * @atomic_print_state: * * If driver subclasses struct &drm_crtc_state, it should implement * this optional hook for printing additional driver specific state. * * Do not call this directly, use drm_atomic_crtc_print_state() * instead. */ void (*atomic_print_state)(struct drm_printer *p, const struct drm_crtc_state *state); }; /** * struct drm_crtc - central CRTC control structure * @dev: parent DRM device * @port: OF node used by drm_of_find_possible_crtcs() * @head: list management * @name: human readable name, can be overwritten by the driver * @mutex: per-CRTC locking * @base: base KMS object for ID tracking etc. * @primary: primary plane for this CRTC * @cursor: cursor plane for this CRTC * @cursor_x: current x position of the cursor, used for universal cursor planes * @cursor_y: current y position of the cursor, used for universal cursor planes * @enabled: is this CRTC enabled? * @mode: current mode timings * @hwmode: mode timings as programmed to hw regs * @x: x position on screen * @y: y position on screen * @funcs: CRTC control functions * @gamma_size: size of gamma ramp * @gamma_store: gamma ramp values * @helper_private: mid-layer private data * @properties: property tracking for this CRTC * * Each CRTC may have one or more connectors associated with it. This structure * allows the CRTC to be controlled. */ struct drm_crtc { struct drm_device *dev; struct device_node *port; struct list_head head; char *name; /** * @mutex: * * 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 ...). Full * modeset also need to grab dev->mode_config.connection_mutex. */ struct drm_modeset_lock mutex; struct drm_mode_object base; /* primary and cursor planes for CRTC */ struct drm_plane *primary; struct drm_plane *cursor; /** * @index: Position inside the mode_config.list, can be used as an array * index. It is invariant over the lifetime of the CRTC. */ unsigned index; /* position of cursor plane on crtc */ int cursor_x; int cursor_y; bool enabled; /* Requested mode from modesetting. */ struct drm_display_mode mode; /* Programmed mode in hw, after adjustments for encoders, * crtc, panel scaling etc. Needed for timestamping etc. */ struct drm_display_mode hwmode; int x, y; const struct drm_crtc_funcs *funcs; /* Legacy FB CRTC gamma size for reporting to userspace */ uint32_t gamma_size; uint16_t *gamma_store; /* if you are using the helper */ const struct drm_crtc_helper_funcs *helper_private; struct drm_object_properties properties; /** * @state: * * Current atomic state for this CRTC. */ struct drm_crtc_state *state; /** * @commit_list: * * List of &drm_crtc_commit structures tracking pending commits. * Protected by @commit_lock. This list doesn't hold its own full * reference, but burrows it from the ongoing commit. Commit entries * must be removed from this list once the commit is fully completed, * but before it's correspoding &drm_atomic_state gets destroyed. */ struct list_head commit_list; /** * @commit_lock: * * Spinlock to protect @commit_list. */ spinlock_t commit_lock; /** * @acquire_ctx: * * Per-CRTC implicit acquire context used by atomic drivers for legacy * IOCTLs, so that atomic drivers can get at the locking acquire * context. */ struct drm_modeset_acquire_ctx *acquire_ctx; #ifdef CONFIG_DEBUG_FS /** * @debugfs_entry: * * Debugfs directory for this CRTC. */ struct dentry *debugfs_entry; /** * @crc: * * Configuration settings of CRC capture. */ struct drm_crtc_crc crc; #endif /** * @fence_context: * * timeline context used for fence operations. */ unsigned int fence_context; /** * @fence_lock: * * spinlock to protect the fences in the fence_context. */ spinlock_t fence_lock; /** * @fence_seqno: * * Seqno variable used as monotonic counter for the fences * created on the CRTC's timeline. */ unsigned long fence_seqno; /** * @timeline_name: * * The name of the CRTC's fence timeline. */ char timeline_name[32]; }; /** * struct drm_mode_set - new values for a CRTC config change * @fb: framebuffer to use for new config * @crtc: CRTC whose configuration we're about to change * @mode: mode timings to use * @x: position of this CRTC relative to @fb * @y: position of this CRTC relative to @fb * @connectors: array of connectors to drive with this CRTC if possible * @num_connectors: size of @connectors array * * Represents a single crtc the connectors that it drives with what mode * and from which framebuffer it scans out from. * * This is used to set modes. */ struct drm_mode_set { struct drm_framebuffer *fb; struct drm_crtc *crtc; struct drm_display_mode *mode; uint32_t x; uint32_t y; struct drm_connector **connectors; size_t num_connectors; }; #define obj_to_crtc(x) container_of(x, struct drm_crtc, base) __printf(6, 7) int drm_crtc_init_with_planes(struct drm_device *dev, struct drm_crtc *crtc, struct drm_plane *primary, struct drm_plane *cursor, const struct drm_crtc_funcs *funcs, const char *name, ...); void drm_crtc_cleanup(struct drm_crtc *crtc); /** * drm_crtc_index - find the index of a registered CRTC * @crtc: CRTC to find index for * * Given a registered CRTC, return the index of that CRTC within a DRM * device's list of CRTCs. */ static inline unsigned int drm_crtc_index(const struct drm_crtc *crtc) { return crtc->index; } /** * drm_crtc_mask - find the mask of a registered CRTC * @crtc: CRTC to find mask for * * Given a registered CRTC, return the mask bit of that CRTC for an * encoder's possible_crtcs field. */ static inline uint32_t drm_crtc_mask(const struct drm_crtc *crtc) { return 1 << drm_crtc_index(crtc); } void drm_crtc_get_hv_timing(const struct drm_display_mode *mode, int *hdisplay, int *vdisplay); int drm_crtc_force_disable(struct drm_crtc *crtc); int drm_crtc_force_disable_all(struct drm_device *dev); int drm_mode_set_config_internal(struct drm_mode_set *set); /* Helpers */ static inline struct drm_crtc *drm_crtc_find(struct drm_device *dev, uint32_t id) { struct drm_mode_object *mo; mo = drm_mode_object_find(dev, id, DRM_MODE_OBJECT_CRTC); return mo ? obj_to_crtc(mo) : NULL; } #define drm_for_each_crtc(crtc, dev) \ list_for_each_entry(crtc, &(dev)->mode_config.crtc_list, head) static inline void assert_drm_connector_list_read_locked(struct drm_mode_config *mode_config) { /* * The connector hotadd/remove code currently grabs both locks when * updating lists. Hence readers need only hold either of them to be * safe and the check amounts to * * WARN_ON(not_holding(A) && not_holding(B)). */ WARN_ON(!mutex_is_locked(&mode_config->mutex) && !drm_modeset_is_locked(&mode_config->connection_mutex)); } #endif /* __DRM_CRTC_H__ */