drm_vblank.h revision 1.5
1 /* $NetBSD: drm_vblank.h,v 1.5 2021/12/19 00:47:17 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 34 #include <drm/drm_file.h> 35 #include <drm/drm_modes.h> 36 37 #ifdef __NetBSD__ /* XXX */ 38 #include <drm/drm_wait_netbsd.h> 39 #endif 40 41 #ifdef __NetBSD__ /* XXX */ 42 #include <drm/drm_wait_netbsd.h> 43 #endif 44 45 struct drm_device; 46 struct drm_crtc; 47 48 /** 49 * struct drm_pending_vblank_event - pending vblank event tracking 50 */ 51 struct drm_pending_vblank_event { 52 /** 53 * @base: Base structure for tracking pending DRM events. 54 */ 55 struct drm_pending_event base; 56 /** 57 * @pipe: drm_crtc_index() of the &drm_crtc this event is for. 58 */ 59 unsigned int pipe; 60 /** 61 * @sequence: frame event should be triggered at 62 */ 63 u64 sequence; 64 /** 65 * @event: Actual event which will be sent to userspace. 66 */ 67 union { 68 /** 69 * @event.base: DRM event base class. 70 */ 71 struct drm_event base; 72 73 /** 74 * @event.vbl: 75 * 76 * Event payload for vblank events, requested through 77 * either the MODE_PAGE_FLIP or MODE_ATOMIC IOCTL. Also 78 * generated by the legacy WAIT_VBLANK IOCTL, but new userspace 79 * should use MODE_QUEUE_SEQUENCE and &event.seq instead. 80 */ 81 struct drm_event_vblank vbl; 82 83 /** 84 * @event.seq: Event payload for the MODE_QUEUEU_SEQUENCE IOCTL. 85 */ 86 struct drm_event_crtc_sequence seq; 87 } event; 88 }; 89 90 /** 91 * struct drm_vblank_crtc - vblank tracking for a CRTC 92 * 93 * This structure tracks the vblank state for one CRTC. 94 * 95 * Note that for historical reasons - the vblank handling code is still shared 96 * with legacy/non-kms drivers - this is a free-standing structure not directly 97 * connected to &struct drm_crtc. But all public interface functions are taking 98 * a &struct drm_crtc to hide this implementation detail. 99 */ 100 struct drm_vblank_crtc { 101 /** 102 * @dev: Pointer to the &drm_device. 103 */ 104 struct drm_device *dev; 105 /** 106 * @queue: Wait queue for vblank waiters. 107 */ 108 wait_queue_head_t queue; 109 /** 110 * @disable_timer: Disable timer for the delayed vblank disabling 111 * hysteresis logic. Vblank disabling is controlled through the 112 * drm_vblank_offdelay module option and the setting of the 113 * &drm_device.max_vblank_count value. 114 */ 115 struct timer_list disable_timer; 116 117 /** 118 * @seqlock: Protect vblank count and time. 119 */ 120 seqlock_t seqlock; 121 122 /** 123 * @count: 124 * 125 * Current software vblank counter. 126 * 127 * Note that for a given vblank counter value drm_crtc_handle_vblank() 128 * and drm_crtc_vblank_count() or drm_crtc_vblank_count_and_time() 129 * provide a barrier: Any writes done before calling 130 * drm_crtc_handle_vblank() will be visible to callers of the later 131 * functions, iff the vblank count is the same or a later one. 132 * 133 * IMPORTANT: This guarantee requires barriers, therefor never access 134 * this field directly. Use drm_crtc_vblank_count() instead. 135 */ 136 atomic64_t count; 137 /** 138 * @time: Vblank timestamp corresponding to @count. 139 */ 140 ktime_t time; 141 142 /** 143 * @refcount: Number of users/waiters of the vblank interrupt. Only when 144 * this refcount reaches 0 can the hardware interrupt be disabled using 145 * @disable_timer. 146 */ 147 atomic_t refcount; 148 /** 149 * @last: Protected by &drm_device.vbl_lock, used for wraparound handling. 150 */ 151 u32 last; 152 /** 153 * @max_vblank_count: 154 * 155 * Maximum value of the vblank registers for this crtc. This value +1 156 * will result in a wrap-around of the vblank register. It is used 157 * by the vblank core to handle wrap-arounds. 158 * 159 * If set to zero the vblank core will try to guess the elapsed vblanks 160 * between times when the vblank interrupt is disabled through 161 * high-precision timestamps. That approach is suffering from small 162 * races and imprecision over longer time periods, hence exposing a 163 * hardware vblank counter is always recommended. 164 * 165 * This is the runtime configurable per-crtc maximum set through 166 * drm_crtc_set_max_vblank_count(). If this is used the driver 167 * must leave the device wide &drm_device.max_vblank_count at zero. 168 * 169 * If non-zero, &drm_crtc_funcs.get_vblank_counter must be set. 170 */ 171 u32 max_vblank_count; 172 /** 173 * @inmodeset: Tracks whether the vblank is disabled due to a modeset. 174 * For legacy driver bit 2 additionally tracks whether an additional 175 * temporary vblank reference has been acquired to paper over the 176 * hardware counter resetting/jumping. KMS drivers should instead just 177 * call drm_crtc_vblank_off() and drm_crtc_vblank_on(), which explicitly 178 * save and restore the vblank count. 179 */ 180 unsigned int inmodeset; 181 /** 182 * @pipe: drm_crtc_index() of the &drm_crtc corresponding to this 183 * structure. 184 */ 185 unsigned int pipe; 186 /** 187 * @framedur_ns: Frame/Field duration in ns, used by 188 * drm_calc_vbltimestamp_from_scanoutpos() and computed by 189 * drm_calc_timestamping_constants(). 190 */ 191 int framedur_ns; 192 /** 193 * @linedur_ns: Line duration in ns, used by 194 * drm_calc_vbltimestamp_from_scanoutpos() and computed by 195 * drm_calc_timestamping_constants(). 196 */ 197 int linedur_ns; 198 199 /** 200 * @hwmode: 201 * 202 * Cache of the current hardware display mode. Only valid when @enabled 203 * is set. This is used by helpers like 204 * drm_calc_vbltimestamp_from_scanoutpos(). We can't just access the 205 * hardware mode by e.g. looking at &drm_crtc_state.adjusted_mode, 206 * because that one is really hard to get from interrupt context. 207 */ 208 struct drm_display_mode hwmode; 209 210 /** 211 * @enabled: Tracks the enabling state of the corresponding &drm_crtc to 212 * avoid double-disabling and hence corrupting saved state. Needed by 213 * drivers not using atomic KMS, since those might go through their CRTC 214 * disabling functions multiple times. 215 */ 216 bool enabled; 217 }; 218 219 int drm_vblank_init(struct drm_device *dev, unsigned int num_crtcs); 220 u64 drm_crtc_vblank_count(struct drm_crtc *crtc); 221 u64 drm_crtc_vblank_count_and_time(struct drm_crtc *crtc, 222 ktime_t *vblanktime); 223 void drm_crtc_send_vblank_event(struct drm_crtc *crtc, 224 struct drm_pending_vblank_event *e); 225 void drm_crtc_arm_vblank_event(struct drm_crtc *crtc, 226 struct drm_pending_vblank_event *e); 227 void drm_vblank_set_event(struct drm_pending_vblank_event *e, 228 u64 *seq, 229 ktime_t *now); 230 bool drm_handle_vblank(struct drm_device *dev, unsigned int pipe); 231 bool drm_crtc_handle_vblank(struct drm_crtc *crtc); 232 int drm_crtc_vblank_get(struct drm_crtc *crtc); 233 void drm_crtc_vblank_put(struct drm_crtc *crtc); 234 void drm_wait_one_vblank(struct drm_device *dev, unsigned int pipe); 235 void drm_crtc_wait_one_vblank(struct drm_crtc *crtc); 236 void drm_crtc_vblank_off(struct drm_crtc *crtc); 237 void drm_crtc_vblank_reset(struct drm_crtc *crtc); 238 void drm_crtc_vblank_on(struct drm_crtc *crtc); 239 u64 drm_crtc_accurate_vblank_count(struct drm_crtc *crtc); 240 void drm_vblank_restore(struct drm_device *dev, unsigned int pipe); 241 void drm_crtc_vblank_restore(struct drm_crtc *crtc); 242 243 bool drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, 244 unsigned int pipe, int *max_error, 245 ktime_t *vblank_time, 246 bool in_vblank_irq); 247 void drm_calc_timestamping_constants(struct drm_crtc *crtc, 248 const struct drm_display_mode *mode); 249 wait_queue_head_t *drm_crtc_vblank_waitqueue(struct drm_crtc *crtc); 250 void drm_crtc_set_max_vblank_count(struct drm_crtc *crtc, 251 u32 max_vblank_count); 252 #endif 253
Indexes created Mon Oct 20 20:10:13 GMT 2025