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