drm_vblank.h revision 1.10
1 /* $NetBSD: drm_vblank.h,v 1.10 2021/12/19 11:52:25 riastradh Exp $ */ 2 3 /* 4 * Copyright 2016 Intel Corp. 5 * 6 * Permission is hereby granted, free of charge, to any person obtaining a 7 * copy of this software and associated documentation files (the "Software"), 8 * to deal in the Software without restriction, including without limitation 9 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 10 * and/or sell copies of the Software, and to permit persons to whom the 11 * Software is furnished to do so, subject to the following conditions: 12 * 13 * The above copyright notice and this permission notice (including the next 14 * paragraph) shall be included in all copies or substantial portions of the 15 * Software. 16 * 17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 20 * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR 21 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, 22 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR 23 * OTHER DEALINGS IN THE SOFTWARE. 24 */ 25 26 #ifndef _DRM_VBLANK_H_ 27 #define _DRM_VBLANK_H_ 28 29 #include <linux/seqlock.h> 30 #include <linux/idr.h> 31 #include <linux/poll.h> 32 #include <linux/timer.h> 33 #include <linux/ktime.h> 34 35 #include <drm/drm_file.h> 36 #include <drm/drm_modes.h> 37 38 #ifdef __NetBSD__ /* XXX */ 39 #include <drm/drm_wait_netbsd.h> 40 #endif 41 42 struct drm_device; 43 struct drm_crtc; 44 45 /** 46 * struct drm_pending_vblank_event - pending vblank event tracking 47 */ 48 struct drm_pending_vblank_event { 49 /** 50 * @base: Base structure for tracking pending DRM events. 51 */ 52 struct drm_pending_event base; 53 /** 54 * @pipe: drm_crtc_index() of the &drm_crtc this event is for. 55 */ 56 unsigned int pipe; 57 /** 58 * @sequence: frame event should be triggered at 59 */ 60 u64 sequence; 61 /** 62 * @event: Actual event which will be sent to userspace. 63 */ 64 union { 65 /** 66 * @event.base: DRM event base class. 67 */ 68 struct drm_event base; 69 70 /** 71 * @event.vbl: 72 * 73 * Event payload for vblank events, requested through 74 * either the MODE_PAGE_FLIP or MODE_ATOMIC IOCTL. Also 75 * generated by the legacy WAIT_VBLANK IOCTL, but new userspace 76 * should use MODE_QUEUE_SEQUENCE and &event.seq instead. 77 */ 78 struct drm_event_vblank vbl; 79 80 /** 81 * @event.seq: Event payload for the MODE_QUEUEU_SEQUENCE IOCTL. 82 */ 83 struct drm_event_crtc_sequence seq; 84 } event; 85 }; 86 87 /** 88 * struct drm_vblank_crtc - vblank tracking for a CRTC 89 * 90 * This structure tracks the vblank state for one CRTC. 91 * 92 * Note that for historical reasons - the vblank handling code is still shared 93 * with legacy/non-kms drivers - this is a free-standing structure not directly 94 * connected to &struct drm_crtc. But all public interface functions are taking 95 * a &struct drm_crtc to hide this implementation detail. 96 */ 97 struct drm_vblank_crtc { 98 /** 99 * @dev: Pointer to the &drm_device. 100 */ 101 struct drm_device *dev; 102 /** 103 * @queue: Wait queue for vblank waiters. 104 */ 105 drm_waitqueue_t queue; 106 /** 107 * @disable_timer: Disable timer for the delayed vblank disabling 108 * hysteresis logic. Vblank disabling is controlled through the 109 * drm_vblank_offdelay module option and the setting of the 110 * &drm_device.max_vblank_count value. 111 */ 112 struct timer_list disable_timer; 113 114 /** 115 * @seqlock: Protect vblank count and time. 116 */ 117 seqlock_t seqlock; 118 119 /** 120 * @count: 121 * 122 * Current software vblank counter. 123 * 124 * Note that for a given vblank counter value drm_crtc_handle_vblank() 125 * and drm_crtc_vblank_count() or drm_crtc_vblank_count_and_time() 126 * provide a barrier: Any writes done before calling 127 * drm_crtc_handle_vblank() will be visible to callers of the later 128 * functions, iff the vblank count is the same or a later one. 129 * 130 * IMPORTANT: This guarantee requires barriers, therefor never access 131 * this field directly. Use drm_crtc_vblank_count() instead. 132 */ 133 atomic64_t count; 134 /** 135 * @time: Vblank timestamp corresponding to @count. 136 */ 137 ktime_t time; 138 139 /** 140 * @refcount: Number of users/waiters of the vblank interrupt. Only when 141 * this refcount reaches 0 can the hardware interrupt be disabled using 142 * @disable_timer. 143 */ 144 atomic_t refcount; 145 /** 146 * @last: Protected by &drm_device.vbl_lock, used for wraparound handling. 147 */ 148 u32 last; 149 /** 150 * @max_vblank_count: 151 * 152 * Maximum value of the vblank registers for this crtc. This value +1 153 * will result in a wrap-around of the vblank register. It is used 154 * by the vblank core to handle wrap-arounds. 155 * 156 * If set to zero the vblank core will try to guess the elapsed vblanks 157 * between times when the vblank interrupt is disabled through 158 * high-precision timestamps. That approach is suffering from small 159 * races and imprecision over longer time periods, hence exposing a 160 * hardware vblank counter is always recommended. 161 * 162 * This is the runtime configurable per-crtc maximum set through 163 * drm_crtc_set_max_vblank_count(). If this is used the driver 164 * must leave the device wide &drm_device.max_vblank_count at zero. 165 * 166 * If non-zero, &drm_crtc_funcs.get_vblank_counter must be set. 167 */ 168 u32 max_vblank_count; 169 /** 170 * @inmodeset: Tracks whether the vblank is disabled due to a modeset. 171 * For legacy driver bit 2 additionally tracks whether an additional 172 * temporary vblank reference has been acquired to paper over the 173 * hardware counter resetting/jumping. KMS drivers should instead just 174 * call drm_crtc_vblank_off() and drm_crtc_vblank_on(), which explicitly 175 * save and restore the vblank count. 176 */ 177 unsigned int inmodeset; 178 /** 179 * @pipe: drm_crtc_index() of the &drm_crtc corresponding to this 180 * structure. 181 */ 182 unsigned int pipe; 183 /** 184 * @framedur_ns: Frame/Field duration in ns, used by 185 * drm_calc_vbltimestamp_from_scanoutpos() and computed by 186 * drm_calc_timestamping_constants(). 187 */ 188 int framedur_ns; 189 /** 190 * @linedur_ns: Line duration in ns, used by 191 * drm_calc_vbltimestamp_from_scanoutpos() and computed by 192 * drm_calc_timestamping_constants(). 193 */ 194 int linedur_ns; 195 196 /** 197 * @hwmode: 198 * 199 * Cache of the current hardware display mode. Only valid when @enabled 200 * is set. This is used by helpers like 201 * drm_calc_vbltimestamp_from_scanoutpos(). We can't just access the 202 * hardware mode by e.g. looking at &drm_crtc_state.adjusted_mode, 203 * because that one is really hard to get from interrupt context. 204 */ 205 struct drm_display_mode hwmode; 206 207 /** 208 * @enabled: Tracks the enabling state of the corresponding &drm_crtc to 209 * avoid double-disabling and hence corrupting saved state. Needed by 210 * drivers not using atomic KMS, since those might go through their CRTC 211 * disabling functions multiple times. 212 */ 213 bool enabled; 214 }; 215 216 int drm_vblank_init(struct drm_device *dev, unsigned int num_crtcs); 217 u64 drm_crtc_vblank_count(struct drm_crtc *crtc); 218 u64 drm_crtc_vblank_count_and_time(struct drm_crtc *crtc, 219 ktime_t *vblanktime); 220 void drm_crtc_send_vblank_event(struct drm_crtc *crtc, 221 struct drm_pending_vblank_event *e); 222 void drm_crtc_arm_vblank_event(struct drm_crtc *crtc, 223 struct drm_pending_vblank_event *e); 224 void drm_vblank_set_event(struct drm_pending_vblank_event *e, 225 u64 *seq, 226 ktime_t *now); 227 bool drm_handle_vblank(struct drm_device *dev, unsigned int pipe); 228 bool drm_crtc_handle_vblank(struct drm_crtc *crtc); 229 int drm_crtc_vblank_get(struct drm_crtc *crtc); 230 void drm_crtc_vblank_put(struct drm_crtc *crtc); 231 void drm_crtc_vblank_put_locked(struct drm_crtc *crtc); 232 void drm_wait_one_vblank(struct drm_device *dev, unsigned int pipe); 233 void drm_crtc_wait_one_vblank(struct drm_crtc *crtc); 234 void drm_crtc_vblank_off(struct drm_crtc *crtc); 235 void drm_crtc_vblank_reset(struct drm_crtc *crtc); 236 void drm_crtc_vblank_on(struct drm_crtc *crtc); 237 u64 drm_crtc_accurate_vblank_count(struct drm_crtc *crtc); 238 void drm_vblank_restore(struct drm_device *dev, unsigned int pipe); 239 void drm_crtc_vblank_restore(struct drm_crtc *crtc); 240 241 bool drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, 242 unsigned int pipe, int *max_error, 243 ktime_t *vblank_time, 244 bool in_vblank_irq); 245 void drm_calc_timestamping_constants(struct drm_crtc *crtc, 246 const struct drm_display_mode *mode); 247 drm_waitqueue_t *drm_crtc_vblank_waitqueue(struct drm_crtc *crtc); 248 void drm_crtc_set_max_vblank_count(struct drm_crtc *crtc, 249 u32 max_vblank_count); 250 #endif 251
Indexes created Mon Oct 20 05:10:11 GMT 2025