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 GEM tracks frontbuffers using a bitmask for all possible
34 * frontbuffer slots through i915_gem_track_fb(). The function in this file are
35 * then called when the contents of the frontbuffer are invalidated, when
36 * frontbuffer rendering has stopped again to flush out all the changes and when
37 * 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 * Note that there's also an older frontbuffer activity tracking scheme which
58 * just tracks general activity. This is done by the various mark_busy and
59 * mark_idle functions. For display power management features using these
60 * functions is deprecated and should be avoided.
61 */
62
63 #include <drm/drmP.h>
64
65 #include "intel_drv.h"
66 #include "intel_frontbuffer.h"
67 #include "i915_drv.h"
68
__intel_fb_obj_invalidate(struct drm_i915_gem_object * obj,enum fb_op_origin origin,unsigned int frontbuffer_bits)69 void __intel_fb_obj_invalidate(struct drm_i915_gem_object *obj,
70 enum fb_op_origin origin,
71 unsigned int frontbuffer_bits)
72 {
73 struct drm_i915_private *dev_priv = to_i915(obj->base.dev);
74
75 if (origin == ORIGIN_CS) {
76 spin_lock(&dev_priv->fb_tracking.lock);
77 dev_priv->fb_tracking.busy_bits |= frontbuffer_bits;
78 dev_priv->fb_tracking.flip_bits &= ~frontbuffer_bits;
79 spin_unlock(&dev_priv->fb_tracking.lock);
80 }
81
82 might_sleep();
83 intel_psr_invalidate(dev_priv, frontbuffer_bits, origin);
84 intel_edp_drrs_invalidate(dev_priv, frontbuffer_bits);
85 intel_fbc_invalidate(dev_priv, frontbuffer_bits, origin);
86 }
87
88 /**
89 * intel_frontbuffer_flush - flush frontbuffer
90 * @dev_priv: i915 device
91 * @frontbuffer_bits: frontbuffer plane tracking bits
92 * @origin: which operation caused the flush
93 *
94 * This function gets called every time rendering on the given planes has
95 * completed and frontbuffer caching can be started again. Flushes will get
96 * delayed if they're blocked by some outstanding asynchronous rendering.
97 *
98 * Can be called without any locks held.
99 */
intel_frontbuffer_flush(struct drm_i915_private * dev_priv,unsigned frontbuffer_bits,enum fb_op_origin origin)100 static void intel_frontbuffer_flush(struct drm_i915_private *dev_priv,
101 unsigned frontbuffer_bits,
102 enum fb_op_origin origin)
103 {
104 /* Delay flushing when rings are still busy.*/
105 spin_lock(&dev_priv->fb_tracking.lock);
106 frontbuffer_bits &= ~dev_priv->fb_tracking.busy_bits;
107 spin_unlock(&dev_priv->fb_tracking.lock);
108
109 if (!frontbuffer_bits)
110 return;
111
112 might_sleep();
113 intel_edp_drrs_flush(dev_priv, frontbuffer_bits);
114 intel_psr_flush(dev_priv, frontbuffer_bits, origin);
115 intel_fbc_flush(dev_priv, frontbuffer_bits, origin);
116 }
117
__intel_fb_obj_flush(struct drm_i915_gem_object * obj,enum fb_op_origin origin,unsigned int frontbuffer_bits)118 void __intel_fb_obj_flush(struct drm_i915_gem_object *obj,
119 enum fb_op_origin origin,
120 unsigned int frontbuffer_bits)
121 {
122 struct drm_i915_private *dev_priv = to_i915(obj->base.dev);
123
124 if (origin == ORIGIN_CS) {
125 spin_lock(&dev_priv->fb_tracking.lock);
126 /* Filter out new bits since rendering started. */
127 frontbuffer_bits &= dev_priv->fb_tracking.busy_bits;
128 dev_priv->fb_tracking.busy_bits &= ~frontbuffer_bits;
129 spin_unlock(&dev_priv->fb_tracking.lock);
130 }
131
132 if (frontbuffer_bits)
133 intel_frontbuffer_flush(dev_priv, frontbuffer_bits, origin);
134 }
135
136 /**
137 * intel_frontbuffer_flip_prepare - prepare asynchronous frontbuffer flip
138 * @dev_priv: i915 device
139 * @frontbuffer_bits: frontbuffer plane tracking bits
140 *
141 * This function gets called after scheduling a flip on @obj. The actual
142 * frontbuffer flushing will be delayed until completion is signalled with
143 * intel_frontbuffer_flip_complete. If an invalidate happens in between this
144 * flush will be cancelled.
145 *
146 * Can be called without any locks held.
147 */
intel_frontbuffer_flip_prepare(struct drm_i915_private * dev_priv,unsigned frontbuffer_bits)148 void intel_frontbuffer_flip_prepare(struct drm_i915_private *dev_priv,
149 unsigned frontbuffer_bits)
150 {
151 spin_lock(&dev_priv->fb_tracking.lock);
152 dev_priv->fb_tracking.flip_bits |= frontbuffer_bits;
153 /* Remove stale busy bits due to the old buffer. */
154 dev_priv->fb_tracking.busy_bits &= ~frontbuffer_bits;
155 spin_unlock(&dev_priv->fb_tracking.lock);
156 }
157
158 /**
159 * intel_frontbuffer_flip_complete - complete asynchronous frontbuffer flip
160 * @dev_priv: i915 device
161 * @frontbuffer_bits: frontbuffer plane tracking bits
162 *
163 * This function gets called after the flip has been latched and will complete
164 * on the next vblank. It will execute the flush if it hasn't been cancelled yet.
165 *
166 * Can be called without any locks held.
167 */
intel_frontbuffer_flip_complete(struct drm_i915_private * dev_priv,unsigned frontbuffer_bits)168 void intel_frontbuffer_flip_complete(struct drm_i915_private *dev_priv,
169 unsigned frontbuffer_bits)
170 {
171 spin_lock(&dev_priv->fb_tracking.lock);
172 /* Mask any cancelled flips. */
173 frontbuffer_bits &= dev_priv->fb_tracking.flip_bits;
174 dev_priv->fb_tracking.flip_bits &= ~frontbuffer_bits;
175 spin_unlock(&dev_priv->fb_tracking.lock);
176
177 if (frontbuffer_bits)
178 intel_frontbuffer_flush(dev_priv,
179 frontbuffer_bits, ORIGIN_FLIP);
180 }
181
182 /**
183 * intel_frontbuffer_flip - synchronous frontbuffer flip
184 * @dev_priv: i915 device
185 * @frontbuffer_bits: frontbuffer plane tracking bits
186 *
187 * This function gets called after scheduling a flip on @obj. This is for
188 * synchronous plane updates which will happen on the next vblank and which will
189 * not get delayed by pending gpu rendering.
190 *
191 * Can be called without any locks held.
192 */
intel_frontbuffer_flip(struct drm_i915_private * dev_priv,unsigned frontbuffer_bits)193 void intel_frontbuffer_flip(struct drm_i915_private *dev_priv,
194 unsigned frontbuffer_bits)
195 {
196 spin_lock(&dev_priv->fb_tracking.lock);
197 /* Remove stale busy bits due to the old buffer. */
198 dev_priv->fb_tracking.busy_bits &= ~frontbuffer_bits;
199 spin_unlock(&dev_priv->fb_tracking.lock);
200
201 intel_frontbuffer_flush(dev_priv, frontbuffer_bits, ORIGIN_FLIP);
202 }
203
