summaryrefslogtreecommitdiffstats
path: root/drivers/gpu/drm/i915/intel_frontbuffer.c
blob: ac85357010b4b652ec15811d9c7d4a3b52ad8ebd (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
/*
 * Copyright © 2014 Intel Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 *
 * Authors:
 *	Daniel Vetter <daniel.vetter@ffwll.ch>
 */

/**
 * DOC: frontbuffer tracking
 *
 * Many features require us to track changes to the currently active
 * frontbuffer, especially rendering targeted at the frontbuffer.
 *
 * To be able to do so GEM tracks frontbuffers using a bitmask for all possible
 * frontbuffer slots through i915_gem_track_fb(). The function in this file are
 * then called when the contents of the frontbuffer are invalidated, when
 * frontbuffer rendering has stopped again to flush out all the changes and when
 * the frontbuffer is exchanged with a flip. Subsystems interested in
 * frontbuffer changes (e.g. PSR, FBC, DRRS) should directly put their callbacks
 * into the relevant places and filter for the frontbuffer slots that they are
 * interested int.
 *
 * On a high level there are two types of powersaving features. The first one
 * work like a special cache (FBC and PSR) and are interested when they should
 * stop caching and when to restart caching. This is done by placing callbacks
 * into the invalidate and the flush functions: At invalidate the caching must
 * be stopped and at flush time it can be restarted. And maybe they need to know
 * when the frontbuffer changes (e.g. when the hw doesn't initiate an invalidate
 * and flush on its own) which can be achieved with placing callbacks into the
 * flip functions.
 *
 * The other type of display power saving feature only cares about busyness
 * (e.g. DRRS). In that case all three (invalidate, flush and flip) indicate
 * busyness. There is no direct way to detect idleness. Instead an idle timer
 * work delayed work should be started from the flush and flip functions and
 * cancelled as soon as busyness is detected.
 *
 * Note that there's also an older frontbuffer activity tracking scheme which
 * just tracks general activity. This is done by the various mark_busy and
 * mark_idle functions. For display power management features using these
 * functions is deprecated and should be avoided.
 */

#include <drm/drmP.h>

#include "intel_drv.h"
#include "i915_drv.h"

/**
 * intel_fb_obj_invalidate - invalidate frontbuffer object
 * @obj: GEM object to invalidate
 * @origin: which operation caused the invalidation
 *
 * This function gets called every time rendering on the given object starts and
 * frontbuffer caching (fbc, low refresh rate for DRRS, panel self refresh) must
 * be invalidated. For ORIGIN_CS any subsequent invalidation will be delayed
 * until the rendering completes or a flip on this frontbuffer plane is
 * scheduled.
 */
void intel_fb_obj_invalidate(struct drm_i915_gem_object *obj,
			     enum fb_op_origin origin)
{
	struct drm_device *dev = obj->base.dev;
	struct drm_i915_private *dev_priv = to_i915(dev);

	WARN_ON(!mutex_is_locked(&dev->struct_mutex));

	if (!obj->frontbuffer_bits)
		return;

	if (origin == ORIGIN_CS) {
		mutex_lock(&dev_priv->fb_tracking.lock);
		dev_priv->fb_tracking.busy_bits
			|= obj->frontbuffer_bits;
		dev_priv->fb_tracking.flip_bits
			&= ~obj->frontbuffer_bits;
		mutex_unlock(&dev_priv->fb_tracking.lock);
	}

	intel_psr_invalidate(dev, obj->frontbuffer_bits);
	intel_edp_drrs_invalidate(dev, obj->frontbuffer_bits);
	intel_fbc_invalidate(dev_priv, obj->frontbuffer_bits, origin);
}

/**
 * intel_frontbuffer_flush - flush frontbuffer
 * @dev: DRM device
 * @frontbuffer_bits: frontbuffer plane tracking bits
 * @origin: which operation caused the flush
 *
 * This function gets called every time rendering on the given planes has
 * completed and frontbuffer caching can be started again. Flushes will get
 * delayed if they're blocked by some outstanding asynchronous rendering.
 *
 * Can be called without any locks held.
 */
static void intel_frontbuffer_flush(struct drm_device *dev,
				    unsigned frontbuffer_bits,
				    enum fb_op_origin origin)
{
	struct drm_i915_private *dev_priv = to_i915(dev);

	/* Delay flushing when rings are still busy.*/
	mutex_lock(&dev_priv->fb_tracking.lock);
	frontbuffer_bits &= ~dev_priv->fb_tracking.busy_bits;
	mutex_unlock(&dev_priv->fb_tracking.lock);

	if (!frontbuffer_bits)
		return;

	intel_edp_drrs_flush(dev, frontbuffer_bits);
	intel_psr_flush(dev, frontbuffer_bits, origin);
	intel_fbc_flush(dev_priv, frontbuffer_bits, origin);
}

/**
 * intel_fb_obj_flush - flush frontbuffer object
 * @obj: GEM object to flush
 * @retire: set when retiring asynchronous rendering
 * @origin: which operation caused the flush
 *
 * This function gets called every time rendering on the given object has
 * completed and frontbuffer caching can be started again. If @retire is true
 * then any delayed flushes will be unblocked.
 */
void intel_fb_obj_flush(struct drm_i915_gem_object *obj,
			bool retire, enum fb_op_origin origin)
{
	struct drm_device *dev = obj->base.dev;
	struct drm_i915_private *dev_priv = to_i915(dev);
	unsigned frontbuffer_bits;

	WARN_ON(!mutex_is_locked(&dev->struct_mutex));

	if (!obj->frontbuffer_bits)
		return;

	frontbuffer_bits = obj->frontbuffer_bits;

	if (retire) {
		mutex_lock(&dev_priv->fb_tracking.lock);
		/* Filter out new bits since rendering started. */
		frontbuffer_bits &= dev_priv->fb_tracking.busy_bits;

		dev_priv->fb_tracking.busy_bits &= ~frontbuffer_bits;
		mutex_unlock(&dev_priv->fb_tracking.lock);
	}

	intel_frontbuffer_flush(dev, frontbuffer_bits, origin);
}

/**
 * intel_frontbuffer_flip_prepare - prepare asynchronous frontbuffer flip
 * @dev: DRM device
 * @frontbuffer_bits: frontbuffer plane tracking bits
 *
 * This function gets called after scheduling a flip on @obj. The actual
 * frontbuffer flushing will be delayed until completion is signalled with
 * intel_frontbuffer_flip_complete. If an invalidate happens in between this
 * flush will be cancelled.
 *
 * Can be called without any locks held.
 */
void intel_frontbuffer_flip_prepare(struct drm_device *dev,
				    unsigned frontbuffer_bits)
{
	struct drm_i915_private *dev_priv = to_i915(dev);

	mutex_lock(&dev_priv->fb_tracking.lock);
	dev_priv->fb_tracking.flip_bits |= frontbuffer_bits;
	/* Remove stale busy bits due to the old buffer. */
	dev_priv->fb_tracking.busy_bits &= ~frontbuffer_bits;
	mutex_unlock(&dev_priv->fb_tracking.lock);

	intel_psr_single_frame_update(dev, frontbuffer_bits);
}

/**
 * intel_frontbuffer_flip_complete - complete asynchronous frontbuffer flip
 * @dev: DRM device
 * @frontbuffer_bits: frontbuffer plane tracking bits
 *
 * This function gets called after the flip has been latched and will complete
 * on the next vblank. It will execute the flush if it hasn't been cancelled yet.
 *
 * Can be called without any locks held.
 */
void intel_frontbuffer_flip_complete(struct drm_device *dev,
				     unsigned frontbuffer_bits)
{
	struct drm_i915_private *dev_priv = to_i915(dev);

	mutex_lock(&dev_priv->fb_tracking.lock);
	/* Mask any cancelled flips. */
	frontbuffer_bits &= dev_priv->fb_tracking.flip_bits;
	dev_priv->fb_tracking.flip_bits &= ~frontbuffer_bits;
	mutex_unlock(&dev_priv->fb_tracking.lock);

	intel_frontbuffer_flush(dev, frontbuffer_bits, ORIGIN_FLIP);
}

/**
 * intel_frontbuffer_flip - synchronous frontbuffer flip
 * @dev: DRM device
 * @frontbuffer_bits: frontbuffer plane tracking bits
 *
 * This function gets called after scheduling a flip on @obj. This is for
 * synchronous plane updates which will happen on the next vblank and which will
 * not get delayed by pending gpu rendering.
 *
 * Can be called without any locks held.
 */
void intel_frontbuffer_flip(struct drm_device *dev,
			    unsigned frontbuffer_bits)
{
	struct drm_i915_private *dev_priv = to_i915(dev);

	mutex_lock(&dev_priv->fb_tracking.lock);
	/* Remove stale busy bits due to the old buffer. */
	dev_priv->fb_tracking.busy_bits &= ~frontbuffer_bits;
	mutex_unlock(&dev_priv->fb_tracking.lock);

	intel_frontbuffer_flush(dev, frontbuffer_bits, ORIGIN_FLIP);
}