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 "display/intel_dp.h" 59 60 #include "i915_drv.h" 61 #include "intel_display_types.h" 62 #include "intel_fbc.h" 63 #include "intel_frontbuffer.h" 64 #include "intel_psr.h" 65 66 /** 67 * frontbuffer_flush - flush frontbuffer 68 * @i915: i915 device 69 * @frontbuffer_bits: frontbuffer plane tracking bits 70 * @origin: which operation caused the flush 71 * 72 * This function gets called every time rendering on the given planes has 73 * completed and frontbuffer caching can be started again. Flushes will get 74 * delayed if they're blocked by some outstanding asynchronous rendering. 75 * 76 * Can be called without any locks held. 77 */ 78 static void frontbuffer_flush(struct drm_i915_private *i915, 79 unsigned int frontbuffer_bits, 80 enum fb_op_origin origin) 81 { 82 /* Delay flushing when rings are still busy.*/ 83 spin_lock(&i915->fb_tracking.lock); 84 frontbuffer_bits &= ~i915->fb_tracking.busy_bits; 85 spin_unlock(&i915->fb_tracking.lock); 86 87 if (!frontbuffer_bits) 88 return; 89 90 might_sleep(); 91 intel_edp_drrs_flush(i915, frontbuffer_bits); 92 intel_psr_flush(i915, frontbuffer_bits, origin); 93 intel_fbc_flush(i915, frontbuffer_bits, origin); 94 } 95 96 /** 97 * intel_frontbuffer_flip_prepare - prepare asynchronous frontbuffer flip 98 * @i915: i915 device 99 * @frontbuffer_bits: frontbuffer plane tracking bits 100 * 101 * This function gets called after scheduling a flip on @obj. The actual 102 * frontbuffer flushing will be delayed until completion is signalled with 103 * intel_frontbuffer_flip_complete. If an invalidate happens in between this 104 * flush will be cancelled. 105 * 106 * Can be called without any locks held. 107 */ 108 void intel_frontbuffer_flip_prepare(struct drm_i915_private *i915, 109 unsigned frontbuffer_bits) 110 { 111 spin_lock(&i915->fb_tracking.lock); 112 i915->fb_tracking.flip_bits |= frontbuffer_bits; 113 /* Remove stale busy bits due to the old buffer. */ 114 i915->fb_tracking.busy_bits &= ~frontbuffer_bits; 115 spin_unlock(&i915->fb_tracking.lock); 116 } 117 118 /** 119 * intel_frontbuffer_flip_complete - complete asynchronous frontbuffer flip 120 * @i915: i915 device 121 * @frontbuffer_bits: frontbuffer plane tracking bits 122 * 123 * This function gets called after the flip has been latched and will complete 124 * on the next vblank. It will execute the flush if it hasn't been cancelled yet. 125 * 126 * Can be called without any locks held. 127 */ 128 void intel_frontbuffer_flip_complete(struct drm_i915_private *i915, 129 unsigned frontbuffer_bits) 130 { 131 spin_lock(&i915->fb_tracking.lock); 132 /* Mask any cancelled flips. */ 133 frontbuffer_bits &= i915->fb_tracking.flip_bits; 134 i915->fb_tracking.flip_bits &= ~frontbuffer_bits; 135 spin_unlock(&i915->fb_tracking.lock); 136 137 if (frontbuffer_bits) 138 frontbuffer_flush(i915, frontbuffer_bits, ORIGIN_FLIP); 139 } 140 141 /** 142 * intel_frontbuffer_flip - synchronous frontbuffer flip 143 * @i915: i915 device 144 * @frontbuffer_bits: frontbuffer plane tracking bits 145 * 146 * This function gets called after scheduling a flip on @obj. This is for 147 * synchronous plane updates which will happen on the next vblank and which will 148 * not get delayed by pending gpu rendering. 149 * 150 * Can be called without any locks held. 151 */ 152 void intel_frontbuffer_flip(struct drm_i915_private *i915, 153 unsigned frontbuffer_bits) 154 { 155 spin_lock(&i915->fb_tracking.lock); 156 /* Remove stale busy bits due to the old buffer. */ 157 i915->fb_tracking.busy_bits &= ~frontbuffer_bits; 158 spin_unlock(&i915->fb_tracking.lock); 159 160 frontbuffer_flush(i915, frontbuffer_bits, ORIGIN_FLIP); 161 } 162 163 void __intel_fb_invalidate(struct intel_frontbuffer *front, 164 enum fb_op_origin origin, 165 unsigned int frontbuffer_bits) 166 { 167 struct drm_i915_private *i915 = to_i915(front->obj->base.dev); 168 169 if (origin == ORIGIN_CS) { 170 spin_lock(&i915->fb_tracking.lock); 171 i915->fb_tracking.busy_bits |= frontbuffer_bits; 172 i915->fb_tracking.flip_bits &= ~frontbuffer_bits; 173 spin_unlock(&i915->fb_tracking.lock); 174 } 175 176 might_sleep(); 177 intel_psr_invalidate(i915, frontbuffer_bits, origin); 178 intel_edp_drrs_invalidate(i915, frontbuffer_bits); 179 intel_fbc_invalidate(i915, frontbuffer_bits, origin); 180 } 181 182 void __intel_fb_flush(struct intel_frontbuffer *front, 183 enum fb_op_origin origin, 184 unsigned int frontbuffer_bits) 185 { 186 struct drm_i915_private *i915 = to_i915(front->obj->base.dev); 187 188 if (origin == ORIGIN_CS) { 189 spin_lock(&i915->fb_tracking.lock); 190 /* Filter out new bits since rendering started. */ 191 frontbuffer_bits &= i915->fb_tracking.busy_bits; 192 i915->fb_tracking.busy_bits &= ~frontbuffer_bits; 193 spin_unlock(&i915->fb_tracking.lock); 194 } 195 196 if (frontbuffer_bits) 197 frontbuffer_flush(i915, frontbuffer_bits, origin); 198 } 199 200 static int frontbuffer_active(struct i915_active *ref) 201 { 202 struct intel_frontbuffer *front = 203 container_of(ref, typeof(*front), write); 204 205 kref_get(&front->ref); 206 return 0; 207 } 208 209 __i915_active_call 210 static void frontbuffer_retire(struct i915_active *ref) 211 { 212 struct intel_frontbuffer *front = 213 container_of(ref, typeof(*front), write); 214 215 intel_frontbuffer_flush(front, ORIGIN_CS); 216 intel_frontbuffer_put(front); 217 } 218 219 static void frontbuffer_release(struct kref *ref) 220 __releases(&to_i915(front->obj->base.dev)->fb_tracking.lock) 221 { 222 struct intel_frontbuffer *front = 223 container_of(ref, typeof(*front), ref); 224 struct drm_i915_gem_object *obj = front->obj; 225 struct i915_vma *vma; 226 227 spin_lock(&obj->vma.lock); 228 for_each_ggtt_vma(vma, obj) { 229 i915_vma_clear_scanout(vma); 230 vma->display_alignment = I915_GTT_MIN_ALIGNMENT; 231 } 232 spin_unlock(&obj->vma.lock); 233 234 RCU_INIT_POINTER(obj->frontbuffer, NULL); 235 spin_unlock(&to_i915(obj->base.dev)->fb_tracking.lock); 236 237 i915_active_fini(&front->write); 238 239 i915_gem_object_put(obj); 240 kfree_rcu(front, rcu); 241 } 242 243 struct intel_frontbuffer * 244 intel_frontbuffer_get(struct drm_i915_gem_object *obj) 245 { 246 struct drm_i915_private *i915 = to_i915(obj->base.dev); 247 struct intel_frontbuffer *front; 248 249 front = __intel_frontbuffer_get(obj); 250 if (front) 251 return front; 252 253 front = kmalloc(sizeof(*front), GFP_KERNEL); 254 if (!front) 255 return NULL; 256 257 front->obj = obj; 258 kref_init(&front->ref); 259 atomic_set(&front->bits, 0); 260 i915_active_init(&front->write, 261 frontbuffer_active, 262 i915_active_may_sleep(frontbuffer_retire)); 263 264 spin_lock(&i915->fb_tracking.lock); 265 if (rcu_access_pointer(obj->frontbuffer)) { 266 kfree(front); 267 front = rcu_dereference_protected(obj->frontbuffer, true); 268 kref_get(&front->ref); 269 } else { 270 i915_gem_object_get(obj); 271 rcu_assign_pointer(obj->frontbuffer, front); 272 } 273 spin_unlock(&i915->fb_tracking.lock); 274 275 return front; 276 } 277 278 void intel_frontbuffer_put(struct intel_frontbuffer *front) 279 { 280 kref_put_lock(&front->ref, 281 frontbuffer_release, 282 &to_i915(front->obj->base.dev)->fb_tracking.lock); 283 } 284 285 /** 286 * intel_frontbuffer_track - update frontbuffer tracking 287 * @old: current buffer for the frontbuffer slots 288 * @new: new buffer for the frontbuffer slots 289 * @frontbuffer_bits: bitmask of frontbuffer slots 290 * 291 * This updates the frontbuffer tracking bits @frontbuffer_bits by clearing them 292 * from @old and setting them in @new. Both @old and @new can be NULL. 293 */ 294 void intel_frontbuffer_track(struct intel_frontbuffer *old, 295 struct intel_frontbuffer *new, 296 unsigned int frontbuffer_bits) 297 { 298 /* 299 * Control of individual bits within the mask are guarded by 300 * the owning plane->mutex, i.e. we can never see concurrent 301 * manipulation of individual bits. But since the bitfield as a whole 302 * is updated using RMW, we need to use atomics in order to update 303 * the bits. 304 */ 305 BUILD_BUG_ON(INTEL_FRONTBUFFER_BITS_PER_PIPE * I915_MAX_PIPES > 306 BITS_PER_TYPE(atomic_t)); 307 308 if (old) { 309 drm_WARN_ON(old->obj->base.dev, 310 !(atomic_read(&old->bits) & frontbuffer_bits)); 311 atomic_andnot(frontbuffer_bits, &old->bits); 312 } 313 314 if (new) { 315 drm_WARN_ON(new->obj->base.dev, 316 atomic_read(&new->bits) & frontbuffer_bits); 317 atomic_or(frontbuffer_bits, &new->bits); 318 } 319 } 320