drm_vblank.h revision 1.4
1 /* $NetBSD: drm_vblank.h,v 1.4 2021/12/19 00:46:29 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 struct drm_device; 42 struct drm_crtc; 43 44 /** 45 * struct drm_pending_vblank_event - pending vblank event tracking 46 */ 47 struct drm_pending_vblank_event { 48 /** 49 * @base: Base structure for tracking pending DRM events. 50 */ 51 struct drm_pending_event base; 52 /** 53 * @pipe: drm_crtc_index() of the &drm_crtc this event is for. 54 */ 55 unsigned int pipe; 56 /** 57 * @sequence: frame event should be triggered at 58 */ 59 u64 sequence; 60 /** 61 * @event: Actual event which will be sent to userspace. 62 */ 63 union { 64 /** 65 * @event.base: DRM event base class. 66 */ 67 struct drm_event base; 68 69 /** 70 * @event.vbl: 71 * 72 * Event payload for vblank events, requested through 73 * either the MODE_PAGE_FLIP or MODE_ATOMIC IOCTL. Also 74 * generated by the legacy WAIT_VBLANK IOCTL, but new userspace 75 * should use MODE_QUEUE_SEQUENCE and &event.seq instead. 76 */ 77 struct drm_event_vblank vbl; 78 79 /** 80 * @event.seq: Event payload for the MODE_QUEUEU_SEQUENCE IOCTL. 81 */ 82 struct drm_event_crtc_sequence seq; 83 } event; 84 }; 85 86 /** 87 * struct drm_vblank_crtc - vblank tracking for a CRTC 88 * 89 * This structure tracks the vblank state for one CRTC. 90 * 91 * Note that for historical reasons - the vblank handling code is still shared 92 * with legacy/non-kms drivers - this is a free-standing structure not directly 93 * connected to &struct drm_crtc. But all public interface functions are taking 94 * a &struct drm_crtc to hide this implementation detail. 95 */ 96 struct drm_vblank_crtc { 97 /** 98 * @dev: Pointer to the &drm_device. 99 */ 100 struct drm_device *dev; 101 /** 102 * @queue: Wait queue for vblank waiters. 103 */ 104 wait_queue_head_t queue; 105 /** 106 * @disable_timer: Disable timer for the delayed vblank disabling 107 * hysteresis logic. Vblank disabling is controlled through the 108 * drm_vblank_offdelay module option and the setting of the 109 * &drm_device.max_vblank_count value. 110 */ 111 struct timer_list disable_timer; 112 113 /** 114 * @seqlock: Protect vblank count and time. 115 */ 116 seqlock_t seqlock; 117 118 /** 119 * @count: 120 * 121 * Current software vblank counter. 122 * 123 * Note that for a given vblank counter value drm_crtc_handle_vblank() 124 * and drm_crtc_vblank_count() or drm_crtc_vblank_count_and_time() 125 * provide a barrier: Any writes done before calling 126 * drm_crtc_handle_vblank() will be visible to callers of the later 127 * functions, iff the vblank count is the same or a later one. 128 * 129 * IMPORTANT: This guarantee requires barriers, therefor never access 130 * this field directly. Use drm_crtc_vblank_count() instead. 131 */ 132 atomic64_t count; 133 /** 134 * @time: Vblank timestamp corresponding to @count. 135 */ 136 ktime_t time; 137 138 /** 139 * @refcount: Number of users/waiters of the vblank interrupt. Only when 140 * this refcount reaches 0 can the hardware interrupt be disabled using 141 * @disable_timer. 142 */ 143 atomic_t refcount; 144 /** 145 * @last: Protected by &drm_device.vbl_lock, used for wraparound handling. 146 */ 147 u32 last; 148 /** 149 * @max_vblank_count: 150 * 151 * Maximum value of the vblank registers for this crtc. This value +1 152 * will result in a wrap-around of the vblank register. It is used 153 * by the vblank core to handle wrap-arounds. 154 * 155 * If set to zero the vblank core will try to guess the elapsed vblanks 156 * between times when the vblank interrupt is disabled through 157 * high-precision timestamps. That approach is suffering from small 158 * races and imprecision over longer time periods, hence exposing a 159 * hardware vblank counter is always recommended. 160 * 161 * This is the runtime configurable per-crtc maximum set through 162 * drm_crtc_set_max_vblank_count(). If this is used the driver 163 * must leave the device wide &drm_device.max_vblank_count at zero. 164 * 165 * If non-zero, &drm_crtc_funcs.get_vblank_counter must be set. 166 */ 167 u32 max_vblank_count; 168 /** 169 * @inmodeset: Tracks whether the vblank is disabled due to a modeset. 170 * For legacy driver bit 2 additionally tracks whether an additional 171 * temporary vblank reference has been acquired to paper over the 172 * hardware counter resetting/jumping. KMS drivers should instead just 173 * call drm_crtc_vblank_off() and drm_crtc_vblank_on(), which explicitly 174 * save and restore the vblank count. 175 */ 176 unsigned int inmodeset; 177 /** 178 * @pipe: drm_crtc_index() of the &drm_crtc corresponding to this 179 * structure. 180 */ 181 unsigned int pipe; 182 /** 183 * @framedur_ns: Frame/Field duration in ns, used by 184 * drm_calc_vbltimestamp_from_scanoutpos() and computed by 185 * drm_calc_timestamping_constants(). 186 */ 187 int framedur_ns; 188 /** 189 * @linedur_ns: Line duration in ns, used by 190 * drm_calc_vbltimestamp_from_scanoutpos() and computed by 191 * drm_calc_timestamping_constants(). 192 */ 193 int linedur_ns; 194 195 /** 196 * @hwmode: 197 * 198 * Cache of the current hardware display mode. Only valid when @enabled 199 * is set. This is used by helpers like 200 * drm_calc_vbltimestamp_from_scanoutpos(). We can't just access the 201 * hardware mode by e.g. looking at &drm_crtc_state.adjusted_mode, 202 * because that one is really hard to get from interrupt context. 203 */ 204 struct drm_display_mode hwmode; 205 206 /** 207 * @enabled: Tracks the enabling state of the corresponding &drm_crtc to 208 * avoid double-disabling and hence corrupting saved state. Needed by 209 * drivers not using atomic KMS, since those might go through their CRTC 210 * disabling functions multiple times. 211 */ 212 bool enabled; 213 }; 214 215 int drm_vblank_init(struct drm_device *dev, unsigned int num_crtcs); 216 u64 drm_crtc_vblank_count(struct drm_crtc *crtc); 217 u64 drm_crtc_vblank_count_and_time(struct drm_crtc *crtc, 218 ktime_t *vblanktime); 219 void drm_crtc_send_vblank_event(struct drm_crtc *crtc, 220 struct drm_pending_vblank_event *e); 221 void drm_crtc_arm_vblank_event(struct drm_crtc *crtc, 222 struct drm_pending_vblank_event *e); 223 void drm_vblank_set_event(struct drm_pending_vblank_event *e, 224 u64 *seq, 225 ktime_t *now); 226 bool drm_handle_vblank(struct drm_device *dev, unsigned int pipe); 227 bool drm_crtc_handle_vblank(struct drm_crtc *crtc); 228 int drm_crtc_vblank_get(struct drm_crtc *crtc); 229 void drm_crtc_vblank_put(struct drm_crtc *crtc); 230 void drm_wait_one_vblank(struct drm_device *dev, unsigned int pipe); 231 void drm_crtc_wait_one_vblank(struct drm_crtc *crtc); 232 void drm_crtc_vblank_off(struct drm_crtc *crtc); 233 void drm_crtc_vblank_reset(struct drm_crtc *crtc); 234 void drm_crtc_vblank_on(struct drm_crtc *crtc); 235 u64 drm_crtc_accurate_vblank_count(struct drm_crtc *crtc); 236 void drm_vblank_restore(struct drm_device *dev, unsigned int pipe); 237 void drm_crtc_vblank_restore(struct drm_crtc *crtc); 238 239 bool drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, 240 unsigned int pipe, int *max_error, 241 ktime_t *vblank_time, 242 bool in_vblank_irq); 243 void drm_calc_timestamping_constants(struct drm_crtc *crtc, 244 const struct drm_display_mode *mode); 245 wait_queue_head_t *drm_crtc_vblank_waitqueue(struct drm_crtc *crtc); 246 void drm_crtc_set_max_vblank_count(struct drm_crtc *crtc, 247 u32 max_vblank_count); 248 #endif 249
Indexes created Sun Oct 19 02:09:48 GMT 2025