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_drv.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 * @i915: i915 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 drm_i915_private *i915, 85 unsigned int frontbuffer_bits, 86 enum fb_op_origin origin) 87 { 88 struct intel_display *display = &i915->display; 89 90 /* Delay flushing when rings are still busy.*/ 91 spin_lock(&i915->display.fb_tracking.lock); 92 frontbuffer_bits &= ~i915->display.fb_tracking.busy_bits; 93 spin_unlock(&i915->display.fb_tracking.lock); 94 95 if (!frontbuffer_bits) 96 return; 97 98 trace_intel_frontbuffer_flush(display, frontbuffer_bits, origin); 99 100 might_sleep(); 101 intel_td_flush(i915); 102 intel_drrs_flush(i915, frontbuffer_bits); 103 intel_psr_flush(display, frontbuffer_bits, origin); 104 intel_fbc_flush(i915, frontbuffer_bits, origin); 105 } 106 107 /** 108 * intel_frontbuffer_flip_prepare - prepare asynchronous frontbuffer flip 109 * @i915: i915 device 110 * @frontbuffer_bits: frontbuffer plane tracking bits 111 * 112 * This function gets called after scheduling a flip on @obj. The actual 113 * frontbuffer flushing will be delayed until completion is signalled with 114 * intel_frontbuffer_flip_complete. If an invalidate happens in between this 115 * flush will be cancelled. 116 * 117 * Can be called without any locks held. 118 */ 119 void intel_frontbuffer_flip_prepare(struct drm_i915_private *i915, 120 unsigned frontbuffer_bits) 121 { 122 spin_lock(&i915->display.fb_tracking.lock); 123 i915->display.fb_tracking.flip_bits |= frontbuffer_bits; 124 /* Remove stale busy bits due to the old buffer. */ 125 i915->display.fb_tracking.busy_bits &= ~frontbuffer_bits; 126 spin_unlock(&i915->display.fb_tracking.lock); 127 } 128 129 /** 130 * intel_frontbuffer_flip_complete - complete asynchronous frontbuffer flip 131 * @i915: i915 device 132 * @frontbuffer_bits: frontbuffer plane tracking bits 133 * 134 * This function gets called after the flip has been latched and will complete 135 * on the next vblank. It will execute the flush if it hasn't been cancelled yet. 136 * 137 * Can be called without any locks held. 138 */ 139 void intel_frontbuffer_flip_complete(struct drm_i915_private *i915, 140 unsigned frontbuffer_bits) 141 { 142 spin_lock(&i915->display.fb_tracking.lock); 143 /* Mask any cancelled flips. */ 144 frontbuffer_bits &= i915->display.fb_tracking.flip_bits; 145 i915->display.fb_tracking.flip_bits &= ~frontbuffer_bits; 146 spin_unlock(&i915->display.fb_tracking.lock); 147 148 if (frontbuffer_bits) 149 frontbuffer_flush(i915, frontbuffer_bits, ORIGIN_FLIP); 150 } 151 152 /** 153 * intel_frontbuffer_flip - synchronous frontbuffer flip 154 * @i915: i915 device 155 * @frontbuffer_bits: frontbuffer plane tracking bits 156 * 157 * This function gets called after scheduling a flip on @obj. This is for 158 * synchronous plane updates which will happen on the next vblank and which will 159 * not get delayed by pending gpu rendering. 160 * 161 * Can be called without any locks held. 162 */ 163 void intel_frontbuffer_flip(struct drm_i915_private *i915, 164 unsigned frontbuffer_bits) 165 { 166 spin_lock(&i915->display.fb_tracking.lock); 167 /* Remove stale busy bits due to the old buffer. */ 168 i915->display.fb_tracking.busy_bits &= ~frontbuffer_bits; 169 spin_unlock(&i915->display.fb_tracking.lock); 170 171 frontbuffer_flush(i915, frontbuffer_bits, ORIGIN_FLIP); 172 } 173 174 void __intel_fb_invalidate(struct intel_frontbuffer *front, 175 enum fb_op_origin origin, 176 unsigned int frontbuffer_bits) 177 { 178 struct intel_display *display = to_intel_display(front->obj->dev); 179 struct drm_i915_private *i915 = to_i915(display->drm); 180 181 if (origin == ORIGIN_CS) { 182 spin_lock(&display->fb_tracking.lock); 183 display->fb_tracking.busy_bits |= frontbuffer_bits; 184 display->fb_tracking.flip_bits &= ~frontbuffer_bits; 185 spin_unlock(&display->fb_tracking.lock); 186 } 187 188 trace_intel_frontbuffer_invalidate(display, frontbuffer_bits, origin); 189 190 might_sleep(); 191 intel_psr_invalidate(display, frontbuffer_bits, origin); 192 intel_drrs_invalidate(i915, frontbuffer_bits); 193 intel_fbc_invalidate(i915, frontbuffer_bits, origin); 194 } 195 196 void __intel_fb_flush(struct intel_frontbuffer *front, 197 enum fb_op_origin origin, 198 unsigned int frontbuffer_bits) 199 { 200 struct intel_display *display = to_intel_display(front->obj->dev); 201 struct drm_i915_private *i915 = to_i915(display->drm); 202 203 if (origin == ORIGIN_CS) { 204 spin_lock(&display->fb_tracking.lock); 205 /* Filter out new bits since rendering started. */ 206 frontbuffer_bits &= display->fb_tracking.busy_bits; 207 display->fb_tracking.busy_bits &= ~frontbuffer_bits; 208 spin_unlock(&display->fb_tracking.lock); 209 } 210 211 if (frontbuffer_bits) 212 frontbuffer_flush(i915, frontbuffer_bits, origin); 213 } 214 215 static void intel_frontbuffer_flush_work(struct work_struct *work) 216 { 217 struct intel_frontbuffer *front = 218 container_of(work, struct intel_frontbuffer, flush_work); 219 220 intel_bo_flush_if_display(front->obj); 221 intel_frontbuffer_flush(front, ORIGIN_DIRTYFB); 222 intel_frontbuffer_put(front); 223 } 224 225 /** 226 * intel_frontbuffer_queue_flush - queue flushing frontbuffer object 227 * @front: GEM object to flush 228 * 229 * This function is targeted for our dirty callback for queueing flush when 230 * dma fence is signales 231 */ 232 void intel_frontbuffer_queue_flush(struct intel_frontbuffer *front) 233 { 234 if (!front) 235 return; 236 237 kref_get(&front->ref); 238 if (!schedule_work(&front->flush_work)) 239 intel_frontbuffer_put(front); 240 } 241 242 static int frontbuffer_active(struct i915_active *ref) 243 { 244 struct intel_frontbuffer *front = 245 container_of(ref, typeof(*front), write); 246 247 kref_get(&front->ref); 248 return 0; 249 } 250 251 static void frontbuffer_retire(struct i915_active *ref) 252 { 253 struct intel_frontbuffer *front = 254 container_of(ref, typeof(*front), write); 255 256 intel_frontbuffer_flush(front, ORIGIN_CS); 257 intel_frontbuffer_put(front); 258 } 259 260 static void frontbuffer_release(struct kref *ref) 261 __releases(&to_intel_display(front->obj->dev)->fb_tracking.lock) 262 { 263 struct intel_frontbuffer *ret, *front = 264 container_of(ref, typeof(*front), ref); 265 struct drm_gem_object *obj = front->obj; 266 struct intel_display *display = to_intel_display(obj->dev); 267 268 drm_WARN_ON(display->drm, atomic_read(&front->bits)); 269 270 i915_ggtt_clear_scanout(to_intel_bo(obj)); 271 272 ret = intel_bo_set_frontbuffer(obj, NULL); 273 drm_WARN_ON(display->drm, ret); 274 spin_unlock(&display->fb_tracking.lock); 275 276 i915_active_fini(&front->write); 277 kfree_rcu(front, rcu); 278 } 279 280 struct intel_frontbuffer * 281 intel_frontbuffer_get(struct drm_gem_object *obj) 282 { 283 struct drm_i915_private *i915 = to_i915(obj->dev); 284 struct intel_frontbuffer *front, *cur; 285 286 front = intel_bo_get_frontbuffer(obj); 287 if (front) 288 return front; 289 290 front = kmalloc(sizeof(*front), GFP_KERNEL); 291 if (!front) 292 return NULL; 293 294 front->obj = obj; 295 kref_init(&front->ref); 296 atomic_set(&front->bits, 0); 297 i915_active_init(&front->write, 298 frontbuffer_active, 299 frontbuffer_retire, 300 I915_ACTIVE_RETIRE_SLEEPS); 301 INIT_WORK(&front->flush_work, intel_frontbuffer_flush_work); 302 303 spin_lock(&i915->display.fb_tracking.lock); 304 cur = intel_bo_set_frontbuffer(obj, front); 305 spin_unlock(&i915->display.fb_tracking.lock); 306 if (cur != front) 307 kfree(front); 308 return cur; 309 } 310 311 void intel_frontbuffer_put(struct intel_frontbuffer *front) 312 { 313 kref_put_lock(&front->ref, 314 frontbuffer_release, 315 &to_intel_display(front->obj->dev)->fb_tracking.lock); 316 } 317 318 /** 319 * intel_frontbuffer_track - update frontbuffer tracking 320 * @old: current buffer for the frontbuffer slots 321 * @new: new buffer for the frontbuffer slots 322 * @frontbuffer_bits: bitmask of frontbuffer slots 323 * 324 * This updates the frontbuffer tracking bits @frontbuffer_bits by clearing them 325 * from @old and setting them in @new. Both @old and @new can be NULL. 326 */ 327 void intel_frontbuffer_track(struct intel_frontbuffer *old, 328 struct intel_frontbuffer *new, 329 unsigned int frontbuffer_bits) 330 { 331 /* 332 * Control of individual bits within the mask are guarded by 333 * the owning plane->mutex, i.e. we can never see concurrent 334 * manipulation of individual bits. But since the bitfield as a whole 335 * is updated using RMW, we need to use atomics in order to update 336 * the bits. 337 */ 338 BUILD_BUG_ON(INTEL_FRONTBUFFER_BITS_PER_PIPE * I915_MAX_PIPES > 339 BITS_PER_TYPE(atomic_t)); 340 BUILD_BUG_ON(INTEL_FRONTBUFFER_BITS_PER_PIPE * I915_MAX_PIPES > 32); 341 BUILD_BUG_ON(I915_MAX_PLANES > INTEL_FRONTBUFFER_BITS_PER_PIPE); 342 343 if (old) { 344 struct intel_display *display = to_intel_display(old->obj->dev); 345 346 drm_WARN_ON(display->drm, 347 !(atomic_read(&old->bits) & frontbuffer_bits)); 348 atomic_andnot(frontbuffer_bits, &old->bits); 349 } 350 351 if (new) { 352 struct intel_display *display = to_intel_display(new->obj->dev); 353 354 drm_WARN_ON(display->drm, 355 atomic_read(&new->bits) & frontbuffer_bits); 356 atomic_or(frontbuffer_bits, &new->bits); 357 } 358 } 359