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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 : 0 : 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 : 0 : spin_lock(&i915->fb_tracking.lock);
84 : 0 : frontbuffer_bits &= ~i915->fb_tracking.busy_bits;
85 : 0 : spin_unlock(&i915->fb_tracking.lock);
86 : :
87 [ # # ]: 0 : if (!frontbuffer_bits)
88 : : return;
89 : :
90 : 0 : might_sleep();
91 : 0 : intel_edp_drrs_flush(i915, frontbuffer_bits);
92 : 0 : intel_psr_flush(i915, frontbuffer_bits, origin);
93 : 0 : 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 : 0 : void intel_frontbuffer_flip_prepare(struct drm_i915_private *i915,
109 : : unsigned frontbuffer_bits)
110 : : {
111 : 0 : spin_lock(&i915->fb_tracking.lock);
112 : 0 : i915->fb_tracking.flip_bits |= frontbuffer_bits;
113 : : /* Remove stale busy bits due to the old buffer. */
114 : 0 : i915->fb_tracking.busy_bits &= ~frontbuffer_bits;
115 : 0 : spin_unlock(&i915->fb_tracking.lock);
116 : 0 : }
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 : 0 : void intel_frontbuffer_flip_complete(struct drm_i915_private *i915,
129 : : unsigned frontbuffer_bits)
130 : : {
131 : 0 : spin_lock(&i915->fb_tracking.lock);
132 : : /* Mask any cancelled flips. */
133 : 0 : frontbuffer_bits &= i915->fb_tracking.flip_bits;
134 : 0 : i915->fb_tracking.flip_bits &= ~frontbuffer_bits;
135 : 0 : spin_unlock(&i915->fb_tracking.lock);
136 : :
137 [ # # ]: 0 : if (frontbuffer_bits)
138 : 0 : frontbuffer_flush(i915, frontbuffer_bits, ORIGIN_FLIP);
139 : 0 : }
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 : 0 : void intel_frontbuffer_flip(struct drm_i915_private *i915,
153 : : unsigned frontbuffer_bits)
154 : : {
155 : 0 : spin_lock(&i915->fb_tracking.lock);
156 : : /* Remove stale busy bits due to the old buffer. */
157 : 0 : i915->fb_tracking.busy_bits &= ~frontbuffer_bits;
158 : 0 : spin_unlock(&i915->fb_tracking.lock);
159 : :
160 : 0 : frontbuffer_flush(i915, frontbuffer_bits, ORIGIN_FLIP);
161 : 0 : }
162 : :
163 : 0 : void __intel_fb_invalidate(struct intel_frontbuffer *front,
164 : : enum fb_op_origin origin,
165 : : unsigned int frontbuffer_bits)
166 : : {
167 [ # # ]: 0 : struct drm_i915_private *i915 = to_i915(front->obj->base.dev);
168 : :
169 [ # # ]: 0 : if (origin == ORIGIN_CS) {
170 : 0 : spin_lock(&i915->fb_tracking.lock);
171 : 0 : i915->fb_tracking.busy_bits |= frontbuffer_bits;
172 : 0 : i915->fb_tracking.flip_bits &= ~frontbuffer_bits;
173 : 0 : spin_unlock(&i915->fb_tracking.lock);
174 : : }
175 : :
176 : 0 : might_sleep();
177 : 0 : intel_psr_invalidate(i915, frontbuffer_bits, origin);
178 : 0 : intel_edp_drrs_invalidate(i915, frontbuffer_bits);
179 : 0 : intel_fbc_invalidate(i915, frontbuffer_bits, origin);
180 : 0 : }
181 : :
182 : 0 : void __intel_fb_flush(struct intel_frontbuffer *front,
183 : : enum fb_op_origin origin,
184 : : unsigned int frontbuffer_bits)
185 : : {
186 [ # # ]: 0 : struct drm_i915_private *i915 = to_i915(front->obj->base.dev);
187 : :
188 [ # # ]: 0 : if (origin == ORIGIN_CS) {
189 : 0 : spin_lock(&i915->fb_tracking.lock);
190 : : /* Filter out new bits since rendering started. */
191 : 0 : frontbuffer_bits &= i915->fb_tracking.busy_bits;
192 : 0 : i915->fb_tracking.busy_bits &= ~frontbuffer_bits;
193 : 0 : spin_unlock(&i915->fb_tracking.lock);
194 : : }
195 : :
196 [ # # ]: 0 : if (frontbuffer_bits)
197 : 0 : frontbuffer_flush(i915, frontbuffer_bits, origin);
198 : 0 : }
199 : :
200 : 0 : static int frontbuffer_active(struct i915_active *ref)
201 : : {
202 : 0 : struct intel_frontbuffer *front =
203 : 0 : container_of(ref, typeof(*front), write);
204 : :
205 : 0 : kref_get(&front->ref);
206 : 0 : return 0;
207 : : }
208 : :
209 : : __i915_active_call
210 : 0 : static void frontbuffer_retire(struct i915_active *ref)
211 : : {
212 : 0 : struct intel_frontbuffer *front =
213 : 0 : container_of(ref, typeof(*front), write);
214 : :
215 : 0 : intel_frontbuffer_flush(front, ORIGIN_CS);
216 : 0 : intel_frontbuffer_put(front);
217 : 0 : }
218 : :
219 : 0 : static void frontbuffer_release(struct kref *ref)
220 : : __releases(&to_i915(front->obj->base.dev)->fb_tracking.lock)
221 : : {
222 : 0 : struct intel_frontbuffer *front =
223 : 0 : container_of(ref, typeof(*front), ref);
224 : 0 : struct drm_i915_gem_object *obj = front->obj;
225 : 0 : struct i915_vma *vma;
226 : :
227 : 0 : spin_lock(&obj->vma.lock);
228 [ # # # # ]: 0 : for_each_ggtt_vma(vma, obj)
229 : 0 : vma->display_alignment = I915_GTT_MIN_ALIGNMENT;
230 : 0 : spin_unlock(&obj->vma.lock);
231 : :
232 : 0 : RCU_INIT_POINTER(obj->frontbuffer, NULL);
233 : 0 : spin_unlock(&to_i915(obj->base.dev)->fb_tracking.lock);
234 : :
235 : 0 : i915_gem_object_put(obj);
236 [ # # ]: 0 : kfree_rcu(front, rcu);
237 : 0 : }
238 : :
239 : : struct intel_frontbuffer *
240 : 0 : intel_frontbuffer_get(struct drm_i915_gem_object *obj)
241 : : {
242 : 0 : struct drm_i915_private *i915 = to_i915(obj->base.dev);
243 : 0 : struct intel_frontbuffer *front;
244 : :
245 : 0 : front = __intel_frontbuffer_get(obj);
246 [ # # ]: 0 : if (front)
247 : : return front;
248 : :
249 : 0 : front = kmalloc(sizeof(*front), GFP_KERNEL);
250 [ # # ]: 0 : if (!front)
251 : : return NULL;
252 : :
253 : 0 : front->obj = obj;
254 : 0 : kref_init(&front->ref);
255 : 0 : atomic_set(&front->bits, 0);
256 : 0 : i915_active_init(&front->write,
257 : : frontbuffer_active,
258 : : i915_active_may_sleep(frontbuffer_retire));
259 : :
260 : 0 : spin_lock(&i915->fb_tracking.lock);
261 [ # # ]: 0 : if (rcu_access_pointer(obj->frontbuffer)) {
262 : 0 : kfree(front);
263 : 0 : front = rcu_dereference_protected(obj->frontbuffer, true);
264 : 0 : kref_get(&front->ref);
265 : : } else {
266 : 0 : i915_gem_object_get(obj);
267 : 0 : rcu_assign_pointer(obj->frontbuffer, front);
268 : : }
269 : 0 : spin_unlock(&i915->fb_tracking.lock);
270 : :
271 : 0 : return front;
272 : : }
273 : :
274 : 0 : void intel_frontbuffer_put(struct intel_frontbuffer *front)
275 : : {
276 : 0 : kref_put_lock(&front->ref,
277 : : frontbuffer_release,
278 : 0 : &to_i915(front->obj->base.dev)->fb_tracking.lock);
279 : 0 : }
280 : :
281 : : /**
282 : : * intel_frontbuffer_track - update frontbuffer tracking
283 : : * @old: current buffer for the frontbuffer slots
284 : : * @new: new buffer for the frontbuffer slots
285 : : * @frontbuffer_bits: bitmask of frontbuffer slots
286 : : *
287 : : * This updates the frontbuffer tracking bits @frontbuffer_bits by clearing them
288 : : * from @old and setting them in @new. Both @old and @new can be NULL.
289 : : */
290 : 0 : void intel_frontbuffer_track(struct intel_frontbuffer *old,
291 : : struct intel_frontbuffer *new,
292 : : unsigned int frontbuffer_bits)
293 : : {
294 : : /*
295 : : * Control of individual bits within the mask are guarded by
296 : : * the owning plane->mutex, i.e. we can never see concurrent
297 : : * manipulation of individual bits. But since the bitfield as a whole
298 : : * is updated using RMW, we need to use atomics in order to update
299 : : * the bits.
300 : : */
301 : 0 : BUILD_BUG_ON(INTEL_FRONTBUFFER_BITS_PER_PIPE * I915_MAX_PIPES >
302 : : BITS_PER_TYPE(atomic_t));
303 : :
304 [ # # ]: 0 : if (old) {
305 [ # # ]: 0 : WARN_ON(!(atomic_read(&old->bits) & frontbuffer_bits));
306 : 0 : atomic_andnot(frontbuffer_bits, &old->bits);
307 : : }
308 : :
309 [ # # ]: 0 : if (new) {
310 [ # # ]: 0 : WARN_ON(atomic_read(&new->bits) & frontbuffer_bits);
311 : 0 : atomic_or(frontbuffer_bits, &new->bits);
312 : : }
313 : 0 : }
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