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 "gem/i915_gem_object_frontbuffer.h" 59 #include "i915_active.h" 60 #include "i915_drv.h" 61 #include "intel_display_trace.h" 62 #include "intel_display_types.h" 63 #include "intel_dp.h" 64 #include "intel_drrs.h" 65 #include "intel_fbc.h" 66 #include "intel_frontbuffer.h" 67 #include "intel_psr.h" 68 #include "intel_tdf.h" 69 70 /** 71 * frontbuffer_flush - flush frontbuffer 72 * @i915: i915 device 73 * @frontbuffer_bits: frontbuffer plane tracking bits 74 * @origin: which operation caused the flush 75 * 76 * This function gets called every time rendering on the given planes has 77 * completed and frontbuffer caching can be started again. Flushes will get 78 * delayed if they're blocked by some outstanding asynchronous rendering. 79 * 80 * Can be called without any locks held. 81 */ 82 static void frontbuffer_flush(struct drm_i915_private *i915, 83 unsigned int frontbuffer_bits, 84 enum fb_op_origin origin) 85 { 86 /* Delay flushing when rings are still busy.*/ 87 spin_lock(&i915->display.fb_tracking.lock); 88 frontbuffer_bits &= ~i915->display.fb_tracking.busy_bits; 89 spin_unlock(&i915->display.fb_tracking.lock); 90 91 if (!frontbuffer_bits) 92 return; 93 94 trace_intel_frontbuffer_flush(i915, frontbuffer_bits, origin); 95 96 might_sleep(); 97 intel_td_flush(i915); 98 intel_drrs_flush(i915, frontbuffer_bits); 99 intel_psr_flush(i915, frontbuffer_bits, origin); 100 intel_fbc_flush(i915, frontbuffer_bits, origin); 101 } 102 103 /** 104 * intel_frontbuffer_flip_prepare - prepare asynchronous frontbuffer flip 105 * @i915: i915 device 106 * @frontbuffer_bits: frontbuffer plane tracking bits 107 * 108 * This function gets called after scheduling a flip on @obj. The actual 109 * frontbuffer flushing will be delayed until completion is signalled with 110 * intel_frontbuffer_flip_complete. If an invalidate happens in between this 111 * flush will be cancelled. 112 * 113 * Can be called without any locks held. 114 */ 115 void intel_frontbuffer_flip_prepare(struct drm_i915_private *i915, 116 unsigned frontbuffer_bits) 117 { 118 spin_lock(&i915->display.fb_tracking.lock); 119 i915->display.fb_tracking.flip_bits |= frontbuffer_bits; 120 /* Remove stale busy bits due to the old buffer. */ 121 i915->display.fb_tracking.busy_bits &= ~frontbuffer_bits; 122 spin_unlock(&i915->display.fb_tracking.lock); 123 } 124 125 /** 126 * intel_frontbuffer_flip_complete - complete asynchronous frontbuffer flip 127 * @i915: i915 device 128 * @frontbuffer_bits: frontbuffer plane tracking bits 129 * 130 * This function gets called after the flip has been latched and will complete 131 * on the next vblank. It will execute the flush if it hasn't been cancelled yet. 132 * 133 * Can be called without any locks held. 134 */ 135 void intel_frontbuffer_flip_complete(struct drm_i915_private *i915, 136 unsigned frontbuffer_bits) 137 { 138 spin_lock(&i915->display.fb_tracking.lock); 139 /* Mask any cancelled flips. */ 140 frontbuffer_bits &= i915->display.fb_tracking.flip_bits; 141 i915->display.fb_tracking.flip_bits &= ~frontbuffer_bits; 142 spin_unlock(&i915->display.fb_tracking.lock); 143 144 if (frontbuffer_bits) 145 frontbuffer_flush(i915, frontbuffer_bits, ORIGIN_FLIP); 146 } 147 148 /** 149 * intel_frontbuffer_flip - synchronous frontbuffer flip 150 * @i915: i915 device 151 * @frontbuffer_bits: frontbuffer plane tracking bits 152 * 153 * This function gets called after scheduling a flip on @obj. This is for 154 * synchronous plane updates which will happen on the next vblank and which will 155 * not get delayed by pending gpu rendering. 156 * 157 * Can be called without any locks held. 158 */ 159 void intel_frontbuffer_flip(struct drm_i915_private *i915, 160 unsigned frontbuffer_bits) 161 { 162 spin_lock(&i915->display.fb_tracking.lock); 163 /* Remove stale busy bits due to the old buffer. */ 164 i915->display.fb_tracking.busy_bits &= ~frontbuffer_bits; 165 spin_unlock(&i915->display.fb_tracking.lock); 166 167 frontbuffer_flush(i915, frontbuffer_bits, ORIGIN_FLIP); 168 } 169 170 void __intel_fb_invalidate(struct intel_frontbuffer *front, 171 enum fb_op_origin origin, 172 unsigned int frontbuffer_bits) 173 { 174 struct drm_i915_private *i915 = intel_bo_to_i915(front->obj); 175 176 if (origin == ORIGIN_CS) { 177 spin_lock(&i915->display.fb_tracking.lock); 178 i915->display.fb_tracking.busy_bits |= frontbuffer_bits; 179 i915->display.fb_tracking.flip_bits &= ~frontbuffer_bits; 180 spin_unlock(&i915->display.fb_tracking.lock); 181 } 182 183 trace_intel_frontbuffer_invalidate(i915, frontbuffer_bits, origin); 184 185 might_sleep(); 186 intel_psr_invalidate(i915, frontbuffer_bits, origin); 187 intel_drrs_invalidate(i915, frontbuffer_bits); 188 intel_fbc_invalidate(i915, frontbuffer_bits, origin); 189 } 190 191 void __intel_fb_flush(struct intel_frontbuffer *front, 192 enum fb_op_origin origin, 193 unsigned int frontbuffer_bits) 194 { 195 struct drm_i915_private *i915 = intel_bo_to_i915(front->obj); 196 197 if (origin == ORIGIN_CS) { 198 spin_lock(&i915->display.fb_tracking.lock); 199 /* Filter out new bits since rendering started. */ 200 frontbuffer_bits &= i915->display.fb_tracking.busy_bits; 201 i915->display.fb_tracking.busy_bits &= ~frontbuffer_bits; 202 spin_unlock(&i915->display.fb_tracking.lock); 203 } 204 205 if (frontbuffer_bits) 206 frontbuffer_flush(i915, frontbuffer_bits, origin); 207 } 208 209 static void intel_frontbuffer_flush_work(struct work_struct *work) 210 { 211 struct intel_frontbuffer *front = 212 container_of(work, struct intel_frontbuffer, flush_work); 213 214 i915_gem_object_flush_if_display(front->obj); 215 intel_frontbuffer_flush(front, ORIGIN_DIRTYFB); 216 intel_frontbuffer_put(front); 217 } 218 219 /** 220 * intel_frontbuffer_queue_flush - queue flushing frontbuffer object 221 * @front: GEM object to flush 222 * 223 * This function is targeted for our dirty callback for queueing flush when 224 * dma fence is signales 225 */ 226 void intel_frontbuffer_queue_flush(struct intel_frontbuffer *front) 227 { 228 if (!front) 229 return; 230 231 kref_get(&front->ref); 232 if (!schedule_work(&front->flush_work)) 233 intel_frontbuffer_put(front); 234 } 235 236 static int frontbuffer_active(struct i915_active *ref) 237 { 238 struct intel_frontbuffer *front = 239 container_of(ref, typeof(*front), write); 240 241 kref_get(&front->ref); 242 return 0; 243 } 244 245 static void frontbuffer_retire(struct i915_active *ref) 246 { 247 struct intel_frontbuffer *front = 248 container_of(ref, typeof(*front), write); 249 250 intel_frontbuffer_flush(front, ORIGIN_CS); 251 intel_frontbuffer_put(front); 252 } 253 254 static void frontbuffer_release(struct kref *ref) 255 __releases(&intel_bo_to_i915(front->obj)->display.fb_tracking.lock) 256 { 257 struct intel_frontbuffer *ret, *front = 258 container_of(ref, typeof(*front), ref); 259 struct drm_i915_gem_object *obj = front->obj; 260 261 drm_WARN_ON(&intel_bo_to_i915(obj)->drm, atomic_read(&front->bits)); 262 263 i915_ggtt_clear_scanout(obj); 264 265 ret = i915_gem_object_set_frontbuffer(obj, NULL); 266 drm_WARN_ON(&intel_bo_to_i915(obj)->drm, ret); 267 spin_unlock(&intel_bo_to_i915(obj)->display.fb_tracking.lock); 268 269 i915_active_fini(&front->write); 270 kfree_rcu(front, rcu); 271 } 272 273 struct intel_frontbuffer * 274 intel_frontbuffer_get(struct drm_i915_gem_object *obj) 275 { 276 struct drm_i915_private *i915 = intel_bo_to_i915(obj); 277 struct intel_frontbuffer *front, *cur; 278 279 front = i915_gem_object_get_frontbuffer(obj); 280 if (front) 281 return front; 282 283 front = kmalloc(sizeof(*front), GFP_KERNEL); 284 if (!front) 285 return NULL; 286 287 front->obj = obj; 288 kref_init(&front->ref); 289 atomic_set(&front->bits, 0); 290 i915_active_init(&front->write, 291 frontbuffer_active, 292 frontbuffer_retire, 293 I915_ACTIVE_RETIRE_SLEEPS); 294 INIT_WORK(&front->flush_work, intel_frontbuffer_flush_work); 295 296 spin_lock(&i915->display.fb_tracking.lock); 297 cur = i915_gem_object_set_frontbuffer(obj, front); 298 spin_unlock(&i915->display.fb_tracking.lock); 299 if (cur != front) 300 kfree(front); 301 return cur; 302 } 303 304 void intel_frontbuffer_put(struct intel_frontbuffer *front) 305 { 306 kref_put_lock(&front->ref, 307 frontbuffer_release, 308 &intel_bo_to_i915(front->obj)->display.fb_tracking.lock); 309 } 310 311 /** 312 * intel_frontbuffer_track - update frontbuffer tracking 313 * @old: current buffer for the frontbuffer slots 314 * @new: new buffer for the frontbuffer slots 315 * @frontbuffer_bits: bitmask of frontbuffer slots 316 * 317 * This updates the frontbuffer tracking bits @frontbuffer_bits by clearing them 318 * from @old and setting them in @new. Both @old and @new can be NULL. 319 */ 320 void intel_frontbuffer_track(struct intel_frontbuffer *old, 321 struct intel_frontbuffer *new, 322 unsigned int frontbuffer_bits) 323 { 324 /* 325 * Control of individual bits within the mask are guarded by 326 * the owning plane->mutex, i.e. we can never see concurrent 327 * manipulation of individual bits. But since the bitfield as a whole 328 * is updated using RMW, we need to use atomics in order to update 329 * the bits. 330 */ 331 BUILD_BUG_ON(INTEL_FRONTBUFFER_BITS_PER_PIPE * I915_MAX_PIPES > 332 BITS_PER_TYPE(atomic_t)); 333 BUILD_BUG_ON(INTEL_FRONTBUFFER_BITS_PER_PIPE * I915_MAX_PIPES > 32); 334 BUILD_BUG_ON(I915_MAX_PLANES > INTEL_FRONTBUFFER_BITS_PER_PIPE); 335 336 if (old) { 337 drm_WARN_ON(&intel_bo_to_i915(old->obj)->drm, 338 !(atomic_read(&old->bits) & frontbuffer_bits)); 339 atomic_andnot(frontbuffer_bits, &old->bits); 340 } 341 342 if (new) { 343 drm_WARN_ON(&intel_bo_to_i915(new->obj)->drm, 344 atomic_read(&new->bits) & frontbuffer_bits); 345 atomic_or(frontbuffer_bits, &new->bits); 346 } 347 } 348