xref: /openbsd-src/sys/dev/pci/drm/i915/display/intel_frontbuffer.c (revision f005ef32267c16bdb134f0e9fa4477dbe07c263a)
1c349dbc7Sjsg /*
2c349dbc7Sjsg  * Copyright © 2014 Intel Corporation
3c349dbc7Sjsg  *
4c349dbc7Sjsg  * Permission is hereby granted, free of charge, to any person obtaining a
5c349dbc7Sjsg  * copy of this software and associated documentation files (the "Software"),
6c349dbc7Sjsg  * to deal in the Software without restriction, including without limitation
7c349dbc7Sjsg  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8c349dbc7Sjsg  * and/or sell copies of the Software, and to permit persons to whom the
9c349dbc7Sjsg  * Software is furnished to do so, subject to the following conditions:
10c349dbc7Sjsg  *
11c349dbc7Sjsg  * The above copyright notice and this permission notice (including the next
12c349dbc7Sjsg  * paragraph) shall be included in all copies or substantial portions of the
13c349dbc7Sjsg  * Software.
14c349dbc7Sjsg  *
15c349dbc7Sjsg  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16c349dbc7Sjsg  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17c349dbc7Sjsg  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
18c349dbc7Sjsg  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19c349dbc7Sjsg  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20c349dbc7Sjsg  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
21c349dbc7Sjsg  * DEALINGS IN THE SOFTWARE.
22c349dbc7Sjsg  *
23c349dbc7Sjsg  * Authors:
24c349dbc7Sjsg  *	Daniel Vetter <daniel.vetter@ffwll.ch>
25c349dbc7Sjsg  */
26c349dbc7Sjsg 
27c349dbc7Sjsg /**
28c349dbc7Sjsg  * DOC: frontbuffer tracking
29c349dbc7Sjsg  *
30c349dbc7Sjsg  * Many features require us to track changes to the currently active
31c349dbc7Sjsg  * frontbuffer, especially rendering targeted at the frontbuffer.
32c349dbc7Sjsg  *
33c349dbc7Sjsg  * To be able to do so we track frontbuffers using a bitmask for all possible
34c349dbc7Sjsg  * frontbuffer slots through intel_frontbuffer_track(). The functions in this
35c349dbc7Sjsg  * file are then called when the contents of the frontbuffer are invalidated,
36c349dbc7Sjsg  * when frontbuffer rendering has stopped again to flush out all the changes
37c349dbc7Sjsg  * and when the frontbuffer is exchanged with a flip. Subsystems interested in
38c349dbc7Sjsg  * frontbuffer changes (e.g. PSR, FBC, DRRS) should directly put their callbacks
39c349dbc7Sjsg  * into the relevant places and filter for the frontbuffer slots that they are
40c349dbc7Sjsg  * interested int.
41c349dbc7Sjsg  *
42c349dbc7Sjsg  * On a high level there are two types of powersaving features. The first one
43c349dbc7Sjsg  * work like a special cache (FBC and PSR) and are interested when they should
44c349dbc7Sjsg  * stop caching and when to restart caching. This is done by placing callbacks
45c349dbc7Sjsg  * into the invalidate and the flush functions: At invalidate the caching must
46c349dbc7Sjsg  * be stopped and at flush time it can be restarted. And maybe they need to know
47c349dbc7Sjsg  * when the frontbuffer changes (e.g. when the hw doesn't initiate an invalidate
48c349dbc7Sjsg  * and flush on its own) which can be achieved with placing callbacks into the
49c349dbc7Sjsg  * flip functions.
50c349dbc7Sjsg  *
51c349dbc7Sjsg  * The other type of display power saving feature only cares about busyness
52c349dbc7Sjsg  * (e.g. DRRS). In that case all three (invalidate, flush and flip) indicate
53c349dbc7Sjsg  * busyness. There is no direct way to detect idleness. Instead an idle timer
54c349dbc7Sjsg  * work delayed work should be started from the flush and flip functions and
55c349dbc7Sjsg  * cancelled as soon as busyness is detected.
56c349dbc7Sjsg  */
57c349dbc7Sjsg 
58c349dbc7Sjsg #include "i915_drv.h"
591bb76ff1Sjsg #include "intel_display_trace.h"
60c349dbc7Sjsg #include "intel_display_types.h"
611bb76ff1Sjsg #include "intel_dp.h"
621bb76ff1Sjsg #include "intel_drrs.h"
63c349dbc7Sjsg #include "intel_fbc.h"
64c349dbc7Sjsg #include "intel_frontbuffer.h"
65c349dbc7Sjsg #include "intel_psr.h"
66c349dbc7Sjsg 
67c349dbc7Sjsg /**
68c349dbc7Sjsg  * frontbuffer_flush - flush frontbuffer
69c349dbc7Sjsg  * @i915: i915 device
70c349dbc7Sjsg  * @frontbuffer_bits: frontbuffer plane tracking bits
71c349dbc7Sjsg  * @origin: which operation caused the flush
72c349dbc7Sjsg  *
73c349dbc7Sjsg  * This function gets called every time rendering on the given planes has
74c349dbc7Sjsg  * completed and frontbuffer caching can be started again. Flushes will get
75c349dbc7Sjsg  * delayed if they're blocked by some outstanding asynchronous rendering.
76c349dbc7Sjsg  *
77c349dbc7Sjsg  * Can be called without any locks held.
78c349dbc7Sjsg  */
frontbuffer_flush(struct drm_i915_private * i915,unsigned int frontbuffer_bits,enum fb_op_origin origin)79c349dbc7Sjsg static void frontbuffer_flush(struct drm_i915_private *i915,
80c349dbc7Sjsg 			      unsigned int frontbuffer_bits,
81c349dbc7Sjsg 			      enum fb_op_origin origin)
82c349dbc7Sjsg {
83c349dbc7Sjsg 	/* Delay flushing when rings are still busy.*/
841bb76ff1Sjsg 	spin_lock(&i915->display.fb_tracking.lock);
851bb76ff1Sjsg 	frontbuffer_bits &= ~i915->display.fb_tracking.busy_bits;
861bb76ff1Sjsg 	spin_unlock(&i915->display.fb_tracking.lock);
87c349dbc7Sjsg 
88c349dbc7Sjsg 	if (!frontbuffer_bits)
89c349dbc7Sjsg 		return;
90c349dbc7Sjsg 
91*f005ef32Sjsg 	trace_intel_frontbuffer_flush(i915, frontbuffer_bits, origin);
925ca02815Sjsg 
93c349dbc7Sjsg 	might_sleep();
941bb76ff1Sjsg 	intel_drrs_flush(i915, frontbuffer_bits);
95c349dbc7Sjsg 	intel_psr_flush(i915, frontbuffer_bits, origin);
96c349dbc7Sjsg 	intel_fbc_flush(i915, frontbuffer_bits, origin);
97c349dbc7Sjsg }
98c349dbc7Sjsg 
99c349dbc7Sjsg /**
100c349dbc7Sjsg  * intel_frontbuffer_flip_prepare - prepare asynchronous frontbuffer flip
101c349dbc7Sjsg  * @i915: i915 device
102c349dbc7Sjsg  * @frontbuffer_bits: frontbuffer plane tracking bits
103c349dbc7Sjsg  *
104c349dbc7Sjsg  * This function gets called after scheduling a flip on @obj. The actual
105c349dbc7Sjsg  * frontbuffer flushing will be delayed until completion is signalled with
106c349dbc7Sjsg  * intel_frontbuffer_flip_complete. If an invalidate happens in between this
107c349dbc7Sjsg  * flush will be cancelled.
108c349dbc7Sjsg  *
109c349dbc7Sjsg  * Can be called without any locks held.
110c349dbc7Sjsg  */
intel_frontbuffer_flip_prepare(struct drm_i915_private * i915,unsigned frontbuffer_bits)111c349dbc7Sjsg void intel_frontbuffer_flip_prepare(struct drm_i915_private *i915,
112c349dbc7Sjsg 				    unsigned frontbuffer_bits)
113c349dbc7Sjsg {
1141bb76ff1Sjsg 	spin_lock(&i915->display.fb_tracking.lock);
1151bb76ff1Sjsg 	i915->display.fb_tracking.flip_bits |= frontbuffer_bits;
116c349dbc7Sjsg 	/* Remove stale busy bits due to the old buffer. */
1171bb76ff1Sjsg 	i915->display.fb_tracking.busy_bits &= ~frontbuffer_bits;
1181bb76ff1Sjsg 	spin_unlock(&i915->display.fb_tracking.lock);
119c349dbc7Sjsg }
120c349dbc7Sjsg 
121c349dbc7Sjsg /**
122c349dbc7Sjsg  * intel_frontbuffer_flip_complete - complete asynchronous frontbuffer flip
123c349dbc7Sjsg  * @i915: i915 device
124c349dbc7Sjsg  * @frontbuffer_bits: frontbuffer plane tracking bits
125c349dbc7Sjsg  *
126c349dbc7Sjsg  * This function gets called after the flip has been latched and will complete
127c349dbc7Sjsg  * on the next vblank. It will execute the flush if it hasn't been cancelled yet.
128c349dbc7Sjsg  *
129c349dbc7Sjsg  * Can be called without any locks held.
130c349dbc7Sjsg  */
intel_frontbuffer_flip_complete(struct drm_i915_private * i915,unsigned frontbuffer_bits)131c349dbc7Sjsg void intel_frontbuffer_flip_complete(struct drm_i915_private *i915,
132c349dbc7Sjsg 				     unsigned frontbuffer_bits)
133c349dbc7Sjsg {
1341bb76ff1Sjsg 	spin_lock(&i915->display.fb_tracking.lock);
135c349dbc7Sjsg 	/* Mask any cancelled flips. */
1361bb76ff1Sjsg 	frontbuffer_bits &= i915->display.fb_tracking.flip_bits;
1371bb76ff1Sjsg 	i915->display.fb_tracking.flip_bits &= ~frontbuffer_bits;
1381bb76ff1Sjsg 	spin_unlock(&i915->display.fb_tracking.lock);
139c349dbc7Sjsg 
140c349dbc7Sjsg 	if (frontbuffer_bits)
141c349dbc7Sjsg 		frontbuffer_flush(i915, frontbuffer_bits, ORIGIN_FLIP);
142c349dbc7Sjsg }
143c349dbc7Sjsg 
144c349dbc7Sjsg /**
145c349dbc7Sjsg  * intel_frontbuffer_flip - synchronous frontbuffer flip
146c349dbc7Sjsg  * @i915: i915 device
147c349dbc7Sjsg  * @frontbuffer_bits: frontbuffer plane tracking bits
148c349dbc7Sjsg  *
149c349dbc7Sjsg  * This function gets called after scheduling a flip on @obj. This is for
150c349dbc7Sjsg  * synchronous plane updates which will happen on the next vblank and which will
151c349dbc7Sjsg  * not get delayed by pending gpu rendering.
152c349dbc7Sjsg  *
153c349dbc7Sjsg  * Can be called without any locks held.
154c349dbc7Sjsg  */
intel_frontbuffer_flip(struct drm_i915_private * i915,unsigned frontbuffer_bits)155c349dbc7Sjsg void intel_frontbuffer_flip(struct drm_i915_private *i915,
156c349dbc7Sjsg 			    unsigned frontbuffer_bits)
157c349dbc7Sjsg {
1581bb76ff1Sjsg 	spin_lock(&i915->display.fb_tracking.lock);
159c349dbc7Sjsg 	/* Remove stale busy bits due to the old buffer. */
1601bb76ff1Sjsg 	i915->display.fb_tracking.busy_bits &= ~frontbuffer_bits;
1611bb76ff1Sjsg 	spin_unlock(&i915->display.fb_tracking.lock);
162c349dbc7Sjsg 
163c349dbc7Sjsg 	frontbuffer_flush(i915, frontbuffer_bits, ORIGIN_FLIP);
164c349dbc7Sjsg }
165c349dbc7Sjsg 
__intel_fb_invalidate(struct intel_frontbuffer * front,enum fb_op_origin origin,unsigned int frontbuffer_bits)166c349dbc7Sjsg void __intel_fb_invalidate(struct intel_frontbuffer *front,
167c349dbc7Sjsg 			   enum fb_op_origin origin,
168c349dbc7Sjsg 			   unsigned int frontbuffer_bits)
169c349dbc7Sjsg {
170*f005ef32Sjsg 	struct drm_i915_private *i915 = intel_bo_to_i915(front->obj);
171c349dbc7Sjsg 
172c349dbc7Sjsg 	if (origin == ORIGIN_CS) {
1731bb76ff1Sjsg 		spin_lock(&i915->display.fb_tracking.lock);
1741bb76ff1Sjsg 		i915->display.fb_tracking.busy_bits |= frontbuffer_bits;
1751bb76ff1Sjsg 		i915->display.fb_tracking.flip_bits &= ~frontbuffer_bits;
1761bb76ff1Sjsg 		spin_unlock(&i915->display.fb_tracking.lock);
177c349dbc7Sjsg 	}
178c349dbc7Sjsg 
179*f005ef32Sjsg 	trace_intel_frontbuffer_invalidate(i915, frontbuffer_bits, origin);
1805ca02815Sjsg 
181c349dbc7Sjsg 	might_sleep();
182c349dbc7Sjsg 	intel_psr_invalidate(i915, frontbuffer_bits, origin);
1831bb76ff1Sjsg 	intel_drrs_invalidate(i915, frontbuffer_bits);
184c349dbc7Sjsg 	intel_fbc_invalidate(i915, frontbuffer_bits, origin);
185c349dbc7Sjsg }
186c349dbc7Sjsg 
__intel_fb_flush(struct intel_frontbuffer * front,enum fb_op_origin origin,unsigned int frontbuffer_bits)187c349dbc7Sjsg void __intel_fb_flush(struct intel_frontbuffer *front,
188c349dbc7Sjsg 		      enum fb_op_origin origin,
189c349dbc7Sjsg 		      unsigned int frontbuffer_bits)
190c349dbc7Sjsg {
191*f005ef32Sjsg 	struct drm_i915_private *i915 = intel_bo_to_i915(front->obj);
192c349dbc7Sjsg 
193c349dbc7Sjsg 	if (origin == ORIGIN_CS) {
1941bb76ff1Sjsg 		spin_lock(&i915->display.fb_tracking.lock);
195c349dbc7Sjsg 		/* Filter out new bits since rendering started. */
1961bb76ff1Sjsg 		frontbuffer_bits &= i915->display.fb_tracking.busy_bits;
1971bb76ff1Sjsg 		i915->display.fb_tracking.busy_bits &= ~frontbuffer_bits;
1981bb76ff1Sjsg 		spin_unlock(&i915->display.fb_tracking.lock);
199c349dbc7Sjsg 	}
200c349dbc7Sjsg 
201c349dbc7Sjsg 	if (frontbuffer_bits)
202c349dbc7Sjsg 		frontbuffer_flush(i915, frontbuffer_bits, origin);
203c349dbc7Sjsg }
204c349dbc7Sjsg 
frontbuffer_active(struct i915_active * ref)205c349dbc7Sjsg static int frontbuffer_active(struct i915_active *ref)
206c349dbc7Sjsg {
207c349dbc7Sjsg 	struct intel_frontbuffer *front =
208c349dbc7Sjsg 		container_of(ref, typeof(*front), write);
209c349dbc7Sjsg 
210c349dbc7Sjsg 	kref_get(&front->ref);
211c349dbc7Sjsg 	return 0;
212c349dbc7Sjsg }
213c349dbc7Sjsg 
frontbuffer_retire(struct i915_active * ref)214c349dbc7Sjsg static void frontbuffer_retire(struct i915_active *ref)
215c349dbc7Sjsg {
216c349dbc7Sjsg 	struct intel_frontbuffer *front =
217c349dbc7Sjsg 		container_of(ref, typeof(*front), write);
218c349dbc7Sjsg 
219c349dbc7Sjsg 	intel_frontbuffer_flush(front, ORIGIN_CS);
220c349dbc7Sjsg 	intel_frontbuffer_put(front);
221c349dbc7Sjsg }
222c349dbc7Sjsg 
frontbuffer_release(struct kref * ref)223c349dbc7Sjsg static void frontbuffer_release(struct kref *ref)
224*f005ef32Sjsg 	__releases(&intel_bo_to_i915(front->obj)->display.fb_tracking.lock)
225c349dbc7Sjsg {
226c349dbc7Sjsg 	struct intel_frontbuffer *front =
227c349dbc7Sjsg 		container_of(ref, typeof(*front), ref);
228c349dbc7Sjsg 	struct drm_i915_gem_object *obj = front->obj;
229c349dbc7Sjsg 
230*f005ef32Sjsg 	drm_WARN_ON(&intel_bo_to_i915(obj)->drm, atomic_read(&front->bits));
2315ca02815Sjsg 
232*f005ef32Sjsg 	i915_ggtt_clear_scanout(obj);
233c349dbc7Sjsg 
234*f005ef32Sjsg 	i915_gem_object_set_frontbuffer(obj, NULL);
235*f005ef32Sjsg 	spin_unlock(&intel_bo_to_i915(obj)->display.fb_tracking.lock);
236c349dbc7Sjsg 
237ad8b1aafSjsg 	i915_active_fini(&front->write);
238ad8b1aafSjsg 
239c349dbc7Sjsg 	i915_gem_object_put(obj);
240c349dbc7Sjsg 	kfree_rcu(front, rcu);
241c349dbc7Sjsg }
242c349dbc7Sjsg 
243c349dbc7Sjsg struct intel_frontbuffer *
intel_frontbuffer_get(struct drm_i915_gem_object * obj)244c349dbc7Sjsg intel_frontbuffer_get(struct drm_i915_gem_object *obj)
245c349dbc7Sjsg {
246*f005ef32Sjsg 	struct drm_i915_private *i915 = intel_bo_to_i915(obj);
247*f005ef32Sjsg 	struct intel_frontbuffer *front, *cur;
248c349dbc7Sjsg 
249*f005ef32Sjsg 	front = i915_gem_object_get_frontbuffer(obj);
250c349dbc7Sjsg 	if (front)
251c349dbc7Sjsg 		return front;
252c349dbc7Sjsg 
253c349dbc7Sjsg 	front = kmalloc(sizeof(*front), GFP_KERNEL);
254c349dbc7Sjsg 	if (!front)
255c349dbc7Sjsg 		return NULL;
256c349dbc7Sjsg 
257c349dbc7Sjsg 	front->obj = obj;
258c349dbc7Sjsg 	kref_init(&front->ref);
259c349dbc7Sjsg 	atomic_set(&front->bits, 0);
260c349dbc7Sjsg 	i915_active_init(&front->write,
261c349dbc7Sjsg 			 frontbuffer_active,
2625ca02815Sjsg 			 frontbuffer_retire,
2635ca02815Sjsg 			 I915_ACTIVE_RETIRE_SLEEPS);
264c349dbc7Sjsg 
2651bb76ff1Sjsg 	spin_lock(&i915->display.fb_tracking.lock);
266*f005ef32Sjsg 	cur = i915_gem_object_set_frontbuffer(obj, front);
2671bb76ff1Sjsg 	spin_unlock(&i915->display.fb_tracking.lock);
268*f005ef32Sjsg 	if (cur != front)
269*f005ef32Sjsg 		kfree(front);
270*f005ef32Sjsg 	return cur;
271c349dbc7Sjsg }
272c349dbc7Sjsg 
intel_frontbuffer_put(struct intel_frontbuffer * front)273c349dbc7Sjsg void intel_frontbuffer_put(struct intel_frontbuffer *front)
274c349dbc7Sjsg {
275c349dbc7Sjsg 	kref_put_lock(&front->ref,
276c349dbc7Sjsg 		      frontbuffer_release,
277*f005ef32Sjsg 		      &intel_bo_to_i915(front->obj)->display.fb_tracking.lock);
278c349dbc7Sjsg }
279c349dbc7Sjsg 
280c349dbc7Sjsg /**
281c349dbc7Sjsg  * intel_frontbuffer_track - update frontbuffer tracking
282c349dbc7Sjsg  * @old: current buffer for the frontbuffer slots
283c349dbc7Sjsg  * @new: new buffer for the frontbuffer slots
284c349dbc7Sjsg  * @frontbuffer_bits: bitmask of frontbuffer slots
285c349dbc7Sjsg  *
286c349dbc7Sjsg  * This updates the frontbuffer tracking bits @frontbuffer_bits by clearing them
287c349dbc7Sjsg  * from @old and setting them in @new. Both @old and @new can be NULL.
288c349dbc7Sjsg  */
intel_frontbuffer_track(struct intel_frontbuffer * old,struct intel_frontbuffer * new,unsigned int frontbuffer_bits)289c349dbc7Sjsg void intel_frontbuffer_track(struct intel_frontbuffer *old,
290c349dbc7Sjsg 			     struct intel_frontbuffer *new,
291c349dbc7Sjsg 			     unsigned int frontbuffer_bits)
292c349dbc7Sjsg {
293c349dbc7Sjsg 	/*
294c349dbc7Sjsg 	 * Control of individual bits within the mask are guarded by
295c349dbc7Sjsg 	 * the owning plane->mutex, i.e. we can never see concurrent
296c349dbc7Sjsg 	 * manipulation of individual bits. But since the bitfield as a whole
297c349dbc7Sjsg 	 * is updated using RMW, we need to use atomics in order to update
298c349dbc7Sjsg 	 * the bits.
299c349dbc7Sjsg 	 */
300c349dbc7Sjsg 	BUILD_BUG_ON(INTEL_FRONTBUFFER_BITS_PER_PIPE * I915_MAX_PIPES >
301c349dbc7Sjsg 		     BITS_PER_TYPE(atomic_t));
3021bb76ff1Sjsg 	BUILD_BUG_ON(INTEL_FRONTBUFFER_BITS_PER_PIPE * I915_MAX_PIPES > 32);
3031bb76ff1Sjsg 	BUILD_BUG_ON(I915_MAX_PLANES > INTEL_FRONTBUFFER_BITS_PER_PIPE);
304c349dbc7Sjsg 
305c349dbc7Sjsg 	if (old) {
306*f005ef32Sjsg 		drm_WARN_ON(&intel_bo_to_i915(old->obj)->drm,
307ad8b1aafSjsg 			    !(atomic_read(&old->bits) & frontbuffer_bits));
308c349dbc7Sjsg 		atomic_andnot(frontbuffer_bits, &old->bits);
309c349dbc7Sjsg 	}
310c349dbc7Sjsg 
311c349dbc7Sjsg 	if (new) {
312*f005ef32Sjsg 		drm_WARN_ON(&intel_bo_to_i915(new->obj)->drm,
313ad8b1aafSjsg 			    atomic_read(&new->bits) & frontbuffer_bits);
314c349dbc7Sjsg 		atomic_or(frontbuffer_bits, &new->bits);
315c349dbc7Sjsg 	}
316c349dbc7Sjsg }
317