xref: /linux/include/drm/drm_vblank.h (revision e21f9e2e862e9eb3dd64eaddb6256b3e5098660f)
1 /*
2  * Copyright 2016 Intel Corp.
3  *
4  * Permission is hereby granted, free of charge, to any person obtaining a
5  * copy of this software and associated documentation files (the "Software"),
6  * to deal in the Software without restriction, including without limitation
7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8  * and/or sell copies of the Software, and to permit persons to whom the
9  * Software is furnished to do so, subject to the following conditions:
10  *
11  * The above copyright notice and this permission notice (including the next
12  * paragraph) shall be included in all copies or substantial portions of the
13  * Software.
14  *
15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
18  * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
19  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
20  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
21  * OTHER DEALINGS IN THE SOFTWARE.
22  */
23 
24 #ifndef _DRM_VBLANK_H_
25 #define _DRM_VBLANK_H_
26 
27 #include <linux/seqlock.h>
28 #include <linux/idr.h>
29 #include <linux/poll.h>
30 
31 #include <drm/drm_file.h>
32 #include <drm/drm_modes.h>
33 #include <uapi/drm/drm.h>
34 
35 struct drm_device;
36 struct drm_crtc;
37 
38 /**
39  * struct drm_pending_vblank_event - pending vblank event tracking
40  */
41 struct drm_pending_vblank_event {
42 	/**
43 	 * @base: Base structure for tracking pending DRM events.
44 	 */
45 	struct drm_pending_event base;
46 	/**
47 	 * @pipe: drm_crtc_index() of the &drm_crtc this event is for.
48 	 */
49 	unsigned int pipe;
50 	/**
51 	 * @sequence: frame event should be triggered at
52 	 */
53 	u64 sequence;
54 	/**
55 	 * @event: Actual event which will be sent to userspace.
56 	 */
57 	union {
58 		/**
59 		 * @event.base: DRM event base class.
60 		 */
61 		struct drm_event base;
62 
63 		/**
64 		 * @event.vbl:
65 		 *
66 		 * Event payload for vblank events, requested through
67 		 * either the MODE_PAGE_FLIP or MODE_ATOMIC IOCTL. Also
68 		 * generated by the legacy WAIT_VBLANK IOCTL, but new userspace
69 		 * should use MODE_QUEUE_SEQUENCE and &event.seq instead.
70 		 */
71 		struct drm_event_vblank vbl;
72 
73 		/**
74 		 * @event.seq: Event payload for the MODE_QUEUEU_SEQUENCE IOCTL.
75 		 */
76 		struct drm_event_crtc_sequence seq;
77 	} event;
78 };
79 
80 /**
81  * struct drm_vblank_crtc - vblank tracking for a CRTC
82  *
83  * This structure tracks the vblank state for one CRTC.
84  *
85  * Note that for historical reasons - the vblank handling code is still shared
86  * with legacy/non-kms drivers - this is a free-standing structure not directly
87  * connected to &struct drm_crtc. But all public interface functions are taking
88  * a &struct drm_crtc to hide this implementation detail.
89  */
90 struct drm_vblank_crtc {
91 	/**
92 	 * @dev: Pointer to the &drm_device.
93 	 */
94 	struct drm_device *dev;
95 	/**
96 	 * @queue: Wait queue for vblank waiters.
97 	 */
98 	wait_queue_head_t queue;	/**< VBLANK wait queue */
99 	/**
100 	 * @disable_timer: Disable timer for the delayed vblank disabling
101 	 * hysteresis logic. Vblank disabling is controlled through the
102 	 * drm_vblank_offdelay module option and the setting of the
103 	 * &drm_device.max_vblank_count value.
104 	 */
105 	struct timer_list disable_timer;
106 
107 	/**
108 	 * @seqlock: Protect vblank count and time.
109 	 */
110 	seqlock_t seqlock;		/* protects vblank count and time */
111 
112 	/**
113 	 * @count: Current software vblank counter.
114 	 */
115 	u64 count;
116 	/**
117 	 * @time: Vblank timestamp corresponding to @count.
118 	 */
119 	ktime_t time;
120 
121 	/**
122 	 * @refcount: Number of users/waiters of the vblank interrupt. Only when
123 	 * this refcount reaches 0 can the hardware interrupt be disabled using
124 	 * @disable_timer.
125 	 */
126 	atomic_t refcount;		/* number of users of vblank interruptsper crtc */
127 	/**
128 	 * @last: Protected by &drm_device.vbl_lock, used for wraparound handling.
129 	 */
130 	u32 last;
131 	/**
132 	 * @inmodeset: Tracks whether the vblank is disabled due to a modeset.
133 	 * For legacy driver bit 2 additionally tracks whether an additional
134 	 * temporary vblank reference has been acquired to paper over the
135 	 * hardware counter resetting/jumping. KMS drivers should instead just
136 	 * call drm_crtc_vblank_off() and drm_crtc_vblank_on(), which explicitly
137 	 * save and restore the vblank count.
138 	 */
139 	unsigned int inmodeset;		/* Display driver is setting mode */
140 	/**
141 	 * @pipe: drm_crtc_index() of the &drm_crtc corresponding to this
142 	 * structure.
143 	 */
144 	unsigned int pipe;
145 	/**
146 	 * @framedur_ns: Frame/Field duration in ns, used by
147 	 * drm_calc_vbltimestamp_from_scanoutpos() and computed by
148 	 * drm_calc_timestamping_constants().
149 	 */
150 	int framedur_ns;
151 	/**
152 	 * @linedur_ns: Line duration in ns, used by
153 	 * drm_calc_vbltimestamp_from_scanoutpos() and computed by
154 	 * drm_calc_timestamping_constants().
155 	 */
156 	int linedur_ns;
157 
158 	/**
159 	 * @hwmode:
160 	 *
161 	 * Cache of the current hardware display mode. Only valid when @enabled
162 	 * is set. This is used by helpers like
163 	 * drm_calc_vbltimestamp_from_scanoutpos(). We can't just access the
164 	 * hardware mode by e.g. looking at &drm_crtc_state.adjusted_mode,
165 	 * because that one is really hard to get from interrupt context.
166 	 */
167 	struct drm_display_mode hwmode;
168 
169 	/**
170 	 * @enabled: Tracks the enabling state of the corresponding &drm_crtc to
171 	 * avoid double-disabling and hence corrupting saved state. Needed by
172 	 * drivers not using atomic KMS, since those might go through their CRTC
173 	 * disabling functions multiple times.
174 	 */
175 	bool enabled;
176 };
177 
178 int drm_vblank_init(struct drm_device *dev, unsigned int num_crtcs);
179 u64 drm_crtc_vblank_count(struct drm_crtc *crtc);
180 u64 drm_crtc_vblank_count_and_time(struct drm_crtc *crtc,
181 				   ktime_t *vblanktime);
182 void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
183 			       struct drm_pending_vblank_event *e);
184 void drm_crtc_arm_vblank_event(struct drm_crtc *crtc,
185 			      struct drm_pending_vblank_event *e);
186 void drm_vblank_set_event(struct drm_pending_vblank_event *e,
187 			  u64 *seq,
188 			  ktime_t *now);
189 bool drm_handle_vblank(struct drm_device *dev, unsigned int pipe);
190 bool drm_crtc_handle_vblank(struct drm_crtc *crtc);
191 int drm_crtc_vblank_get(struct drm_crtc *crtc);
192 void drm_crtc_vblank_put(struct drm_crtc *crtc);
193 void drm_wait_one_vblank(struct drm_device *dev, unsigned int pipe);
194 void drm_crtc_wait_one_vblank(struct drm_crtc *crtc);
195 void drm_crtc_vblank_off(struct drm_crtc *crtc);
196 void drm_crtc_vblank_reset(struct drm_crtc *crtc);
197 void drm_crtc_vblank_on(struct drm_crtc *crtc);
198 u64 drm_crtc_accurate_vblank_count(struct drm_crtc *crtc);
199 void drm_vblank_restore(struct drm_device *dev, unsigned int pipe);
200 void drm_crtc_vblank_restore(struct drm_crtc *crtc);
201 
202 bool drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev,
203 					   unsigned int pipe, int *max_error,
204 					   ktime_t *vblank_time,
205 					   bool in_vblank_irq);
206 void drm_calc_timestamping_constants(struct drm_crtc *crtc,
207 				     const struct drm_display_mode *mode);
208 wait_queue_head_t *drm_crtc_vblank_waitqueue(struct drm_crtc *crtc);
209 #endif
210