1 /* 2 * Copyright © 2014 Intel Corporation 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 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 21 * DEALINGS IN THE SOFTWARE. 22 * 23 * Authors: 24 * Daniel Vetter <daniel.vetter@ffwll.ch> 25 */ 26 27 /** 28 * DOC: frontbuffer tracking 29 * 30 * Many features require us to track changes to the currently active 31 * frontbuffer, especially rendering targeted at the frontbuffer. 32 * 33 * To be able to do so we track frontbuffers using a bitmask for all possible 34 * frontbuffer slots through intel_frontbuffer_track(). The functions in this 35 * file are then called when the contents of the frontbuffer are invalidated, 36 * when frontbuffer rendering has stopped again to flush out all the changes 37 * and when the frontbuffer is exchanged with a flip. Subsystems interested in 38 * frontbuffer changes (e.g. PSR, FBC, DRRS) should directly put their callbacks 39 * into the relevant places and filter for the frontbuffer slots that they are 40 * interested int. 41 * 42 * On a high level there are two types of powersaving features. The first one 43 * work like a special cache (FBC and PSR) and are interested when they should 44 * stop caching and when to restart caching. This is done by placing callbacks 45 * into the invalidate and the flush functions: At invalidate the caching must 46 * be stopped and at flush time it can be restarted. And maybe they need to know 47 * when the frontbuffer changes (e.g. when the hw doesn't initiate an invalidate 48 * and flush on its own) which can be achieved with placing callbacks into the 49 * flip functions. 50 * 51 * The other type of display power saving feature only cares about busyness 52 * (e.g. DRRS). In that case all three (invalidate, flush and flip) indicate 53 * busyness. There is no direct way to detect idleness. Instead an idle timer 54 * work delayed work should be started from the flush and flip functions and 55 * cancelled as soon as busyness is detected. 56 */ 57 58 #include <drm/drm_gem.h> 59 60 #include "i915_active.h" 61 #include "i915_vma.h" 62 #include "intel_bo.h" 63 #include "intel_display_trace.h" 64 #include "intel_display_types.h" 65 #include "intel_dp.h" 66 #include "intel_drrs.h" 67 #include "intel_fbc.h" 68 #include "intel_frontbuffer.h" 69 #include "intel_psr.h" 70 #include "intel_tdf.h" 71 72 /** 73 * frontbuffer_flush - flush frontbuffer 74 * @display: display device 75 * @frontbuffer_bits: frontbuffer plane tracking bits 76 * @origin: which operation caused the flush 77 * 78 * This function gets called every time rendering on the given planes has 79 * completed and frontbuffer caching can be started again. Flushes will get 80 * delayed if they're blocked by some outstanding asynchronous rendering. 81 * 82 * Can be called without any locks held. 83 */ 84 static void frontbuffer_flush(struct intel_display *display, 85 unsigned int frontbuffer_bits, 86 enum fb_op_origin origin) 87 { 88 /* Delay flushing when rings are still busy.*/ 89 spin_lock(&display->fb_tracking.lock); 90 frontbuffer_bits &= ~display->fb_tracking.busy_bits; 91 spin_unlock(&display->fb_tracking.lock); 92 93 if (!frontbuffer_bits) 94 return; 95 96 trace_intel_frontbuffer_flush(display, frontbuffer_bits, origin); 97 98 might_sleep(); 99 intel_td_flush(display); 100 intel_drrs_flush(display, frontbuffer_bits); 101 intel_psr_flush(display, frontbuffer_bits, origin); 102 intel_fbc_flush(display, frontbuffer_bits, origin); 103 } 104 105 /** 106 * intel_frontbuffer_flip_prepare - prepare asynchronous frontbuffer flip 107 * @display: display device 108 * @frontbuffer_bits: frontbuffer plane tracking bits 109 * 110 * This function gets called after scheduling a flip on @obj. The actual 111 * frontbuffer flushing will be delayed until completion is signalled with 112 * intel_frontbuffer_flip_complete. If an invalidate happens in between this 113 * flush will be cancelled. 114 * 115 * Can be called without any locks held. 116 */ 117 void intel_frontbuffer_flip_prepare(struct intel_display *display, 118 unsigned frontbuffer_bits) 119 { 120 spin_lock(&display->fb_tracking.lock); 121 display->fb_tracking.flip_bits |= frontbuffer_bits; 122 /* Remove stale busy bits due to the old buffer. */ 123 display->fb_tracking.busy_bits &= ~frontbuffer_bits; 124 spin_unlock(&display->fb_tracking.lock); 125 } 126 127 /** 128 * intel_frontbuffer_flip_complete - complete asynchronous frontbuffer flip 129 * @display: display device 130 * @frontbuffer_bits: frontbuffer plane tracking bits 131 * 132 * This function gets called after the flip has been latched and will complete 133 * on the next vblank. It will execute the flush if it hasn't been cancelled yet. 134 * 135 * Can be called without any locks held. 136 */ 137 void intel_frontbuffer_flip_complete(struct intel_display *display, 138 unsigned frontbuffer_bits) 139 { 140 spin_lock(&display->fb_tracking.lock); 141 /* Mask any cancelled flips. */ 142 frontbuffer_bits &= display->fb_tracking.flip_bits; 143 display->fb_tracking.flip_bits &= ~frontbuffer_bits; 144 spin_unlock(&display->fb_tracking.lock); 145 146 if (frontbuffer_bits) 147 frontbuffer_flush(display, frontbuffer_bits, ORIGIN_FLIP); 148 } 149 150 /** 151 * intel_frontbuffer_flip - synchronous frontbuffer flip 152 * @display: display device 153 * @frontbuffer_bits: frontbuffer plane tracking bits 154 * 155 * This function gets called after scheduling a flip on @obj. This is for 156 * synchronous plane updates which will happen on the next vblank and which will 157 * not get delayed by pending gpu rendering. 158 * 159 * Can be called without any locks held. 160 */ 161 void intel_frontbuffer_flip(struct intel_display *display, 162 unsigned frontbuffer_bits) 163 { 164 spin_lock(&display->fb_tracking.lock); 165 /* Remove stale busy bits due to the old buffer. */ 166 display->fb_tracking.busy_bits &= ~frontbuffer_bits; 167 spin_unlock(&display->fb_tracking.lock); 168 169 frontbuffer_flush(display, frontbuffer_bits, ORIGIN_FLIP); 170 } 171 172 void __intel_fb_invalidate(struct intel_frontbuffer *front, 173 enum fb_op_origin origin, 174 unsigned int frontbuffer_bits) 175 { 176 struct intel_display *display = to_intel_display(front->obj->dev); 177 178 if (origin == ORIGIN_CS) { 179 spin_lock(&display->fb_tracking.lock); 180 display->fb_tracking.busy_bits |= frontbuffer_bits; 181 display->fb_tracking.flip_bits &= ~frontbuffer_bits; 182 spin_unlock(&display->fb_tracking.lock); 183 } 184 185 trace_intel_frontbuffer_invalidate(display, frontbuffer_bits, origin); 186 187 might_sleep(); 188 intel_psr_invalidate(display, frontbuffer_bits, origin); 189 intel_drrs_invalidate(display, frontbuffer_bits); 190 intel_fbc_invalidate(display, frontbuffer_bits, origin); 191 } 192 193 void __intel_fb_flush(struct intel_frontbuffer *front, 194 enum fb_op_origin origin, 195 unsigned int frontbuffer_bits) 196 { 197 struct intel_display *display = to_intel_display(front->obj->dev); 198 199 if (origin == ORIGIN_CS) { 200 spin_lock(&display->fb_tracking.lock); 201 /* Filter out new bits since rendering started. */ 202 frontbuffer_bits &= display->fb_tracking.busy_bits; 203 display->fb_tracking.busy_bits &= ~frontbuffer_bits; 204 spin_unlock(&display->fb_tracking.lock); 205 } 206 207 if (frontbuffer_bits) 208 frontbuffer_flush(display, frontbuffer_bits, origin); 209 } 210 211 static void intel_frontbuffer_flush_work(struct work_struct *work) 212 { 213 struct intel_frontbuffer *front = 214 container_of(work, struct intel_frontbuffer, flush_work); 215 216 intel_bo_flush_if_display(front->obj); 217 intel_frontbuffer_flush(front, ORIGIN_DIRTYFB); 218 intel_frontbuffer_put(front); 219 } 220 221 /** 222 * intel_frontbuffer_queue_flush - queue flushing frontbuffer object 223 * @front: GEM object to flush 224 * 225 * This function is targeted for our dirty callback for queueing flush when 226 * dma fence is signals 227 */ 228 void intel_frontbuffer_queue_flush(struct intel_frontbuffer *front) 229 { 230 if (!front) 231 return; 232 233 kref_get(&front->ref); 234 if (!schedule_work(&front->flush_work)) 235 intel_frontbuffer_put(front); 236 } 237 238 static int frontbuffer_active(struct i915_active *ref) 239 { 240 struct intel_frontbuffer *front = 241 container_of(ref, typeof(*front), write); 242 243 kref_get(&front->ref); 244 return 0; 245 } 246 247 static void frontbuffer_retire(struct i915_active *ref) 248 { 249 struct intel_frontbuffer *front = 250 container_of(ref, typeof(*front), write); 251 252 intel_frontbuffer_flush(front, ORIGIN_CS); 253 intel_frontbuffer_put(front); 254 } 255 256 static void frontbuffer_release(struct kref *ref) 257 __releases(&to_intel_display(front->obj->dev)->fb_tracking.lock) 258 { 259 struct intel_frontbuffer *ret, *front = 260 container_of(ref, typeof(*front), ref); 261 struct drm_gem_object *obj = front->obj; 262 struct intel_display *display = to_intel_display(obj->dev); 263 264 drm_WARN_ON(display->drm, atomic_read(&front->bits)); 265 266 i915_ggtt_clear_scanout(to_intel_bo(obj)); 267 268 ret = intel_bo_set_frontbuffer(obj, NULL); 269 drm_WARN_ON(display->drm, ret); 270 spin_unlock(&display->fb_tracking.lock); 271 272 i915_active_fini(&front->write); 273 kfree_rcu(front, rcu); 274 } 275 276 struct intel_frontbuffer * 277 intel_frontbuffer_get(struct drm_gem_object *obj) 278 { 279 struct intel_display *display = to_intel_display(obj->dev); 280 struct intel_frontbuffer *front, *cur; 281 282 front = intel_bo_get_frontbuffer(obj); 283 if (front) 284 return front; 285 286 front = kmalloc(sizeof(*front), GFP_KERNEL); 287 if (!front) 288 return NULL; 289 290 front->obj = obj; 291 kref_init(&front->ref); 292 atomic_set(&front->bits, 0); 293 i915_active_init(&front->write, 294 frontbuffer_active, 295 frontbuffer_retire, 296 I915_ACTIVE_RETIRE_SLEEPS); 297 INIT_WORK(&front->flush_work, intel_frontbuffer_flush_work); 298 299 spin_lock(&display->fb_tracking.lock); 300 cur = intel_bo_set_frontbuffer(obj, front); 301 spin_unlock(&display->fb_tracking.lock); 302 if (cur != front) 303 kfree(front); 304 return cur; 305 } 306 307 void intel_frontbuffer_put(struct intel_frontbuffer *front) 308 { 309 kref_put_lock(&front->ref, 310 frontbuffer_release, 311 &to_intel_display(front->obj->dev)->fb_tracking.lock); 312 } 313 314 /** 315 * intel_frontbuffer_track - update frontbuffer tracking 316 * @old: current buffer for the frontbuffer slots 317 * @new: new buffer for the frontbuffer slots 318 * @frontbuffer_bits: bitmask of frontbuffer slots 319 * 320 * This updates the frontbuffer tracking bits @frontbuffer_bits by clearing them 321 * from @old and setting them in @new. Both @old and @new can be NULL. 322 */ 323 void intel_frontbuffer_track(struct intel_frontbuffer *old, 324 struct intel_frontbuffer *new, 325 unsigned int frontbuffer_bits) 326 { 327 /* 328 * Control of individual bits within the mask are guarded by 329 * the owning plane->mutex, i.e. we can never see concurrent 330 * manipulation of individual bits. But since the bitfield as a whole 331 * is updated using RMW, we need to use atomics in order to update 332 * the bits. 333 */ 334 BUILD_BUG_ON(INTEL_FRONTBUFFER_BITS_PER_PIPE * I915_MAX_PIPES > 335 BITS_PER_TYPE(atomic_t)); 336 BUILD_BUG_ON(INTEL_FRONTBUFFER_BITS_PER_PIPE * I915_MAX_PIPES > 32); 337 BUILD_BUG_ON(I915_MAX_PLANES > INTEL_FRONTBUFFER_BITS_PER_PIPE); 338 339 if (old) { 340 struct intel_display *display = to_intel_display(old->obj->dev); 341 342 drm_WARN_ON(display->drm, 343 !(atomic_read(&old->bits) & frontbuffer_bits)); 344 atomic_andnot(frontbuffer_bits, &old->bits); 345 } 346 347 if (new) { 348 struct intel_display *display = to_intel_display(new->obj->dev); 349 350 drm_WARN_ON(display->drm, 351 atomic_read(&new->bits) & frontbuffer_bits); 352 atomic_or(frontbuffer_bits, &new->bits); 353 } 354 } 355