2 * Copyright 2016 Intel Corp.
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24 #ifndef _DRM_VBLANK_H_
25 #define _DRM_VBLANK_H_
27 #include <linux/seqlock.h>
28 #include <linux/idr.h>
29 #include <linux/poll.h>
30 #include <linux/kthread.h>
32 #include <drm/drm_file.h>
33 #include <drm/drm_modes.h>
37 struct drm_vblank_work;
40 * struct drm_pending_vblank_event - pending vblank event tracking
42 struct drm_pending_vblank_event {
44 * @base: Base structure for tracking pending DRM events.
46 struct drm_pending_event base;
48 * @pipe: drm_crtc_index() of the &drm_crtc this event is for.
52 * @sequence: frame event should be triggered at
56 * @event: Actual event which will be sent to userspace.
60 * @event.base: DRM event base class.
62 struct drm_event base;
67 * Event payload for vblank events, requested through
68 * either the MODE_PAGE_FLIP or MODE_ATOMIC IOCTL. Also
69 * generated by the legacy WAIT_VBLANK IOCTL, but new userspace
70 * should use MODE_QUEUE_SEQUENCE and &event.seq instead.
72 struct drm_event_vblank vbl;
75 * @event.seq: Event payload for the MODE_QUEUEU_SEQUENCE IOCTL.
77 struct drm_event_crtc_sequence seq;
82 * struct drm_vblank_crtc - vblank tracking for a CRTC
84 * This structure tracks the vblank state for one CRTC.
86 * Note that for historical reasons - the vblank handling code is still shared
87 * with legacy/non-kms drivers - this is a free-standing structure not directly
88 * connected to &struct drm_crtc. But all public interface functions are taking
89 * a &struct drm_crtc to hide this implementation detail.
91 struct drm_vblank_crtc {
93 * @dev: Pointer to the &drm_device.
95 struct drm_device *dev;
97 * @queue: Wait queue for vblank waiters.
99 wait_queue_head_t queue;
101 * @disable_timer: Disable timer for the delayed vblank disabling
102 * hysteresis logic. Vblank disabling is controlled through the
103 * drm_vblank_offdelay module option and the setting of the
104 * &drm_device.max_vblank_count value.
106 struct timer_list disable_timer;
109 * @seqlock: Protect vblank count and time.
116 * Current software vblank counter.
118 * Note that for a given vblank counter value drm_crtc_handle_vblank()
119 * and drm_crtc_vblank_count() or drm_crtc_vblank_count_and_time()
120 * provide a barrier: Any writes done before calling
121 * drm_crtc_handle_vblank() will be visible to callers of the later
122 * functions, iff the vblank count is the same or a later one.
124 * IMPORTANT: This guarantee requires barriers, therefor never access
125 * this field directly. Use drm_crtc_vblank_count() instead.
129 * @time: Vblank timestamp corresponding to @count.
134 * @refcount: Number of users/waiters of the vblank interrupt. Only when
135 * this refcount reaches 0 can the hardware interrupt be disabled using
140 * @last: Protected by &drm_device.vbl_lock, used for wraparound handling.
146 * Maximum value of the vblank registers for this crtc. This value +1
147 * will result in a wrap-around of the vblank register. It is used
148 * by the vblank core to handle wrap-arounds.
150 * If set to zero the vblank core will try to guess the elapsed vblanks
151 * between times when the vblank interrupt is disabled through
152 * high-precision timestamps. That approach is suffering from small
153 * races and imprecision over longer time periods, hence exposing a
154 * hardware vblank counter is always recommended.
156 * This is the runtime configurable per-crtc maximum set through
157 * drm_crtc_set_max_vblank_count(). If this is used the driver
158 * must leave the device wide &drm_device.max_vblank_count at zero.
160 * If non-zero, &drm_crtc_funcs.get_vblank_counter must be set.
162 u32 max_vblank_count;
164 * @inmodeset: Tracks whether the vblank is disabled due to a modeset.
165 * For legacy driver bit 2 additionally tracks whether an additional
166 * temporary vblank reference has been acquired to paper over the
167 * hardware counter resetting/jumping. KMS drivers should instead just
168 * call drm_crtc_vblank_off() and drm_crtc_vblank_on(), which explicitly
169 * save and restore the vblank count.
171 unsigned int inmodeset;
173 * @pipe: drm_crtc_index() of the &drm_crtc corresponding to this
178 * @framedur_ns: Frame/Field duration in ns, used by
179 * drm_crtc_vblank_helper_get_vblank_timestamp() and computed by
180 * drm_calc_timestamping_constants().
184 * @linedur_ns: Line duration in ns, used by
185 * drm_crtc_vblank_helper_get_vblank_timestamp() and computed by
186 * drm_calc_timestamping_constants().
193 * Cache of the current hardware display mode. Only valid when @enabled
194 * is set. This is used by helpers like
195 * drm_crtc_vblank_helper_get_vblank_timestamp(). We can't just access
196 * the hardware mode by e.g. looking at &drm_crtc_state.adjusted_mode,
197 * because that one is really hard to get from interrupt context.
199 struct drm_display_mode hwmode;
202 * @enabled: Tracks the enabling state of the corresponding &drm_crtc to
203 * avoid double-disabling and hence corrupting saved state. Needed by
204 * drivers not using atomic KMS, since those might go through their CRTC
205 * disabling functions multiple times.
210 * @worker: The &kthread_worker used for executing vblank works.
212 struct kthread_worker *worker;
215 * @pending_work: A list of scheduled &drm_vblank_work items that are
216 * waiting for a future vblank.
218 struct list_head pending_work;
221 * @work_wait_queue: The wait queue used for signaling that a
222 * &drm_vblank_work item has either finished executing, or was
225 wait_queue_head_t work_wait_queue;
228 int drm_vblank_init(struct drm_device *dev, unsigned int num_crtcs);
229 bool drm_dev_has_vblank(const struct drm_device *dev);
230 u64 drm_crtc_vblank_count(struct drm_crtc *crtc);
231 u64 drm_crtc_vblank_count_and_time(struct drm_crtc *crtc,
232 ktime_t *vblanktime);
233 void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
234 struct drm_pending_vblank_event *e);
235 void drm_crtc_arm_vblank_event(struct drm_crtc *crtc,
236 struct drm_pending_vblank_event *e);
237 void drm_vblank_set_event(struct drm_pending_vblank_event *e,
240 bool drm_handle_vblank(struct drm_device *dev, unsigned int pipe);
241 bool drm_crtc_handle_vblank(struct drm_crtc *crtc);
242 int drm_crtc_vblank_get(struct drm_crtc *crtc);
243 void drm_crtc_vblank_put(struct drm_crtc *crtc);
244 void drm_wait_one_vblank(struct drm_device *dev, unsigned int pipe);
245 void drm_crtc_wait_one_vblank(struct drm_crtc *crtc);
246 void drm_crtc_vblank_off(struct drm_crtc *crtc);
247 void drm_crtc_vblank_reset(struct drm_crtc *crtc);
248 void drm_crtc_vblank_on(struct drm_crtc *crtc);
249 u64 drm_crtc_accurate_vblank_count(struct drm_crtc *crtc);
250 void drm_crtc_vblank_restore(struct drm_crtc *crtc);
252 void drm_calc_timestamping_constants(struct drm_crtc *crtc,
253 const struct drm_display_mode *mode);
254 wait_queue_head_t *drm_crtc_vblank_waitqueue(struct drm_crtc *crtc);
255 void drm_crtc_set_max_vblank_count(struct drm_crtc *crtc,
256 u32 max_vblank_count);
259 * Helpers for struct drm_crtc_funcs
262 typedef bool (*drm_vblank_get_scanout_position_func)(struct drm_crtc *crtc,
264 int *vpos, int *hpos,
267 const struct drm_display_mode *mode);
270 drm_crtc_vblank_helper_get_vblank_timestamp_internal(struct drm_crtc *crtc,
272 ktime_t *vblank_time,
274 drm_vblank_get_scanout_position_func get_scanout_position);
275 bool drm_crtc_vblank_helper_get_vblank_timestamp(struct drm_crtc *crtc,
277 ktime_t *vblank_time,