xref: /linux/drivers/gpu/drm/i915/display/intel_drrs.c (revision a1ff5a7d78a036d6c2178ee5acd6ba4946243800)
1 // SPDX-License-Identifier: MIT
2 /*
3  * Copyright © 2021 Intel Corporation
4  */
5 
6 #include "i915_drv.h"
7 #include "i915_reg.h"
8 #include "intel_atomic.h"
9 #include "intel_de.h"
10 #include "intel_display_types.h"
11 #include "intel_drrs.h"
12 #include "intel_frontbuffer.h"
13 #include "intel_panel.h"
14 
15 /**
16  * DOC: Display Refresh Rate Switching (DRRS)
17  *
18  * Display Refresh Rate Switching (DRRS) is a power conservation feature
19  * which enables swtching between low and high refresh rates,
20  * dynamically, based on the usage scenario. This feature is applicable
21  * for internal panels.
22  *
23  * Indication that the panel supports DRRS is given by the panel EDID, which
24  * would list multiple refresh rates for one resolution.
25  *
26  * DRRS is of 2 types - static and seamless.
27  * Static DRRS involves changing refresh rate (RR) by doing a full modeset
28  * (may appear as a blink on screen) and is used in dock-undock scenario.
29  * Seamless DRRS involves changing RR without any visual effect to the user
30  * and can be used during normal system usage. This is done by programming
31  * certain registers.
32  *
33  * Support for static/seamless DRRS may be indicated in the VBT based on
34  * inputs from the panel spec.
35  *
36  * DRRS saves power by switching to low RR based on usage scenarios.
37  *
38  * The implementation is based on frontbuffer tracking implementation.  When
39  * there is a disturbance on the screen triggered by user activity or a periodic
40  * system activity, DRRS is disabled (RR is changed to high RR).  When there is
41  * no movement on screen, after a timeout of 1 second, a switch to low RR is
42  * made.
43  *
44  * For integration with frontbuffer tracking code, intel_drrs_invalidate()
45  * and intel_drrs_flush() are called.
46  *
47  * DRRS can be further extended to support other internal panels and also
48  * the scenario of video playback wherein RR is set based on the rate
49  * requested by userspace.
50  */
51 
intel_drrs_type_str(enum drrs_type drrs_type)52 const char *intel_drrs_type_str(enum drrs_type drrs_type)
53 {
54 	static const char * const str[] = {
55 		[DRRS_TYPE_NONE] = "none",
56 		[DRRS_TYPE_STATIC] = "static",
57 		[DRRS_TYPE_SEAMLESS] = "seamless",
58 	};
59 
60 	if (drrs_type >= ARRAY_SIZE(str))
61 		return "<invalid>";
62 
63 	return str[drrs_type];
64 }
65 
intel_cpu_transcoder_has_drrs(struct drm_i915_private * i915,enum transcoder cpu_transcoder)66 bool intel_cpu_transcoder_has_drrs(struct drm_i915_private *i915,
67 				   enum transcoder cpu_transcoder)
68 {
69 	if (HAS_DOUBLE_BUFFERED_M_N(i915))
70 		return true;
71 
72 	return intel_cpu_transcoder_has_m2_n2(i915, cpu_transcoder);
73 }
74 
75 static void
intel_drrs_set_refresh_rate_pipeconf(struct intel_crtc * crtc,enum drrs_refresh_rate refresh_rate)76 intel_drrs_set_refresh_rate_pipeconf(struct intel_crtc *crtc,
77 				     enum drrs_refresh_rate refresh_rate)
78 {
79 	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
80 	enum transcoder cpu_transcoder = crtc->drrs.cpu_transcoder;
81 	u32 bit;
82 
83 	if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv))
84 		bit = TRANSCONF_REFRESH_RATE_ALT_VLV;
85 	else
86 		bit = TRANSCONF_REFRESH_RATE_ALT_ILK;
87 
88 	intel_de_rmw(dev_priv, TRANSCONF(dev_priv, cpu_transcoder),
89 		     bit, refresh_rate == DRRS_REFRESH_RATE_LOW ? bit : 0);
90 }
91 
92 static void
intel_drrs_set_refresh_rate_m_n(struct intel_crtc * crtc,enum drrs_refresh_rate refresh_rate)93 intel_drrs_set_refresh_rate_m_n(struct intel_crtc *crtc,
94 				enum drrs_refresh_rate refresh_rate)
95 {
96 	intel_cpu_transcoder_set_m1_n1(crtc, crtc->drrs.cpu_transcoder,
97 				       refresh_rate == DRRS_REFRESH_RATE_LOW ?
98 				       &crtc->drrs.m2_n2 : &crtc->drrs.m_n);
99 }
100 
intel_drrs_is_active(struct intel_crtc * crtc)101 bool intel_drrs_is_active(struct intel_crtc *crtc)
102 {
103 	return crtc->drrs.cpu_transcoder != INVALID_TRANSCODER;
104 }
105 
intel_drrs_set_state(struct intel_crtc * crtc,enum drrs_refresh_rate refresh_rate)106 static void intel_drrs_set_state(struct intel_crtc *crtc,
107 				 enum drrs_refresh_rate refresh_rate)
108 {
109 	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
110 
111 	if (refresh_rate == crtc->drrs.refresh_rate)
112 		return;
113 
114 	if (intel_cpu_transcoder_has_m2_n2(dev_priv, crtc->drrs.cpu_transcoder))
115 		intel_drrs_set_refresh_rate_pipeconf(crtc, refresh_rate);
116 	else
117 		intel_drrs_set_refresh_rate_m_n(crtc, refresh_rate);
118 
119 	crtc->drrs.refresh_rate = refresh_rate;
120 }
121 
intel_drrs_schedule_work(struct intel_crtc * crtc)122 static void intel_drrs_schedule_work(struct intel_crtc *crtc)
123 {
124 	struct drm_i915_private *i915 = to_i915(crtc->base.dev);
125 
126 	mod_delayed_work(i915->unordered_wq, &crtc->drrs.work, msecs_to_jiffies(1000));
127 }
128 
intel_drrs_frontbuffer_bits(const struct intel_crtc_state * crtc_state)129 static unsigned int intel_drrs_frontbuffer_bits(const struct intel_crtc_state *crtc_state)
130 {
131 	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
132 	struct drm_i915_private *i915 = to_i915(crtc->base.dev);
133 	unsigned int frontbuffer_bits;
134 
135 	frontbuffer_bits = INTEL_FRONTBUFFER_ALL_MASK(crtc->pipe);
136 
137 	for_each_intel_crtc_in_pipe_mask(&i915->drm, crtc,
138 					 crtc_state->joiner_pipes)
139 		frontbuffer_bits |= INTEL_FRONTBUFFER_ALL_MASK(crtc->pipe);
140 
141 	return frontbuffer_bits;
142 }
143 
144 /**
145  * intel_drrs_activate - activate DRRS
146  * @crtc_state: the crtc state
147  *
148  * Activates DRRS on the crtc.
149  */
intel_drrs_activate(const struct intel_crtc_state * crtc_state)150 void intel_drrs_activate(const struct intel_crtc_state *crtc_state)
151 {
152 	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
153 
154 	if (!crtc_state->has_drrs)
155 		return;
156 
157 	if (!crtc_state->hw.active)
158 		return;
159 
160 	if (intel_crtc_is_joiner_secondary(crtc_state))
161 		return;
162 
163 	mutex_lock(&crtc->drrs.mutex);
164 
165 	crtc->drrs.cpu_transcoder = crtc_state->cpu_transcoder;
166 	crtc->drrs.m_n = crtc_state->dp_m_n;
167 	crtc->drrs.m2_n2 = crtc_state->dp_m2_n2;
168 	crtc->drrs.frontbuffer_bits = intel_drrs_frontbuffer_bits(crtc_state);
169 	crtc->drrs.busy_frontbuffer_bits = 0;
170 
171 	intel_drrs_schedule_work(crtc);
172 
173 	mutex_unlock(&crtc->drrs.mutex);
174 }
175 
176 /**
177  * intel_drrs_deactivate - deactivate DRRS
178  * @old_crtc_state: the old crtc state
179  *
180  * Deactivates DRRS on the crtc.
181  */
intel_drrs_deactivate(const struct intel_crtc_state * old_crtc_state)182 void intel_drrs_deactivate(const struct intel_crtc_state *old_crtc_state)
183 {
184 	struct intel_crtc *crtc = to_intel_crtc(old_crtc_state->uapi.crtc);
185 
186 	if (!old_crtc_state->has_drrs)
187 		return;
188 
189 	if (!old_crtc_state->hw.active)
190 		return;
191 
192 	if (intel_crtc_is_joiner_secondary(old_crtc_state))
193 		return;
194 
195 	mutex_lock(&crtc->drrs.mutex);
196 
197 	if (intel_drrs_is_active(crtc))
198 		intel_drrs_set_state(crtc, DRRS_REFRESH_RATE_HIGH);
199 
200 	crtc->drrs.cpu_transcoder = INVALID_TRANSCODER;
201 	crtc->drrs.frontbuffer_bits = 0;
202 	crtc->drrs.busy_frontbuffer_bits = 0;
203 
204 	mutex_unlock(&crtc->drrs.mutex);
205 
206 	cancel_delayed_work_sync(&crtc->drrs.work);
207 }
208 
intel_drrs_downclock_work(struct work_struct * work)209 static void intel_drrs_downclock_work(struct work_struct *work)
210 {
211 	struct intel_crtc *crtc = container_of(work, typeof(*crtc), drrs.work.work);
212 
213 	mutex_lock(&crtc->drrs.mutex);
214 
215 	if (intel_drrs_is_active(crtc) && !crtc->drrs.busy_frontbuffer_bits)
216 		intel_drrs_set_state(crtc, DRRS_REFRESH_RATE_LOW);
217 
218 	mutex_unlock(&crtc->drrs.mutex);
219 }
220 
intel_drrs_frontbuffer_update(struct drm_i915_private * dev_priv,unsigned int all_frontbuffer_bits,bool invalidate)221 static void intel_drrs_frontbuffer_update(struct drm_i915_private *dev_priv,
222 					  unsigned int all_frontbuffer_bits,
223 					  bool invalidate)
224 {
225 	struct intel_crtc *crtc;
226 
227 	for_each_intel_crtc(&dev_priv->drm, crtc) {
228 		unsigned int frontbuffer_bits;
229 
230 		mutex_lock(&crtc->drrs.mutex);
231 
232 		frontbuffer_bits = all_frontbuffer_bits & crtc->drrs.frontbuffer_bits;
233 		if (!frontbuffer_bits) {
234 			mutex_unlock(&crtc->drrs.mutex);
235 			continue;
236 		}
237 
238 		if (invalidate)
239 			crtc->drrs.busy_frontbuffer_bits |= frontbuffer_bits;
240 		else
241 			crtc->drrs.busy_frontbuffer_bits &= ~frontbuffer_bits;
242 
243 		/* flush/invalidate means busy screen hence upclock */
244 		intel_drrs_set_state(crtc, DRRS_REFRESH_RATE_HIGH);
245 
246 		/*
247 		 * flush also means no more activity hence schedule downclock, if all
248 		 * other fbs are quiescent too
249 		 */
250 		if (!crtc->drrs.busy_frontbuffer_bits)
251 			intel_drrs_schedule_work(crtc);
252 		else
253 			cancel_delayed_work(&crtc->drrs.work);
254 
255 		mutex_unlock(&crtc->drrs.mutex);
256 	}
257 }
258 
259 /**
260  * intel_drrs_invalidate - Disable Idleness DRRS
261  * @dev_priv: i915 device
262  * @frontbuffer_bits: frontbuffer plane tracking bits
263  *
264  * This function gets called everytime rendering on the given planes start.
265  * Hence DRRS needs to be Upclocked, i.e. (LOW_RR -> HIGH_RR).
266  *
267  * Dirty frontbuffers relevant to DRRS are tracked in busy_frontbuffer_bits.
268  */
intel_drrs_invalidate(struct drm_i915_private * dev_priv,unsigned int frontbuffer_bits)269 void intel_drrs_invalidate(struct drm_i915_private *dev_priv,
270 			   unsigned int frontbuffer_bits)
271 {
272 	intel_drrs_frontbuffer_update(dev_priv, frontbuffer_bits, true);
273 }
274 
275 /**
276  * intel_drrs_flush - Restart Idleness DRRS
277  * @dev_priv: i915 device
278  * @frontbuffer_bits: frontbuffer plane tracking bits
279  *
280  * This function gets called every time rendering on the given planes has
281  * completed or flip on a crtc is completed. So DRRS should be upclocked
282  * (LOW_RR -> HIGH_RR). And also Idleness detection should be started again,
283  * if no other planes are dirty.
284  *
285  * Dirty frontbuffers relevant to DRRS are tracked in busy_frontbuffer_bits.
286  */
intel_drrs_flush(struct drm_i915_private * dev_priv,unsigned int frontbuffer_bits)287 void intel_drrs_flush(struct drm_i915_private *dev_priv,
288 		      unsigned int frontbuffer_bits)
289 {
290 	intel_drrs_frontbuffer_update(dev_priv, frontbuffer_bits, false);
291 }
292 
293 /**
294  * intel_drrs_crtc_init - Init DRRS for CRTC
295  * @crtc: crtc
296  *
297  * This function is called only once at driver load to initialize basic
298  * DRRS stuff.
299  *
300  */
intel_drrs_crtc_init(struct intel_crtc * crtc)301 void intel_drrs_crtc_init(struct intel_crtc *crtc)
302 {
303 	INIT_DELAYED_WORK(&crtc->drrs.work, intel_drrs_downclock_work);
304 	mutex_init(&crtc->drrs.mutex);
305 	crtc->drrs.cpu_transcoder = INVALID_TRANSCODER;
306 }
307 
intel_drrs_debugfs_status_show(struct seq_file * m,void * unused)308 static int intel_drrs_debugfs_status_show(struct seq_file *m, void *unused)
309 {
310 	struct intel_crtc *crtc = m->private;
311 	struct drm_i915_private *i915 = to_i915(crtc->base.dev);
312 	const struct intel_crtc_state *crtc_state;
313 	int ret;
314 
315 	ret = drm_modeset_lock_single_interruptible(&crtc->base.mutex);
316 	if (ret)
317 		return ret;
318 
319 	crtc_state = to_intel_crtc_state(crtc->base.state);
320 
321 	mutex_lock(&crtc->drrs.mutex);
322 
323 	seq_printf(m, "DRRS capable: %s\n",
324 		   str_yes_no(intel_cpu_transcoder_has_drrs(i915,
325 							    crtc_state->cpu_transcoder)));
326 
327 	seq_printf(m, "DRRS enabled: %s\n",
328 		   str_yes_no(crtc_state->has_drrs));
329 
330 	seq_printf(m, "DRRS active: %s\n",
331 		   str_yes_no(intel_drrs_is_active(crtc)));
332 
333 	seq_printf(m, "DRRS refresh rate: %s\n",
334 		   crtc->drrs.refresh_rate == DRRS_REFRESH_RATE_LOW ?
335 		   "low" : "high");
336 
337 	seq_printf(m, "DRRS busy frontbuffer bits: 0x%x\n",
338 		   crtc->drrs.busy_frontbuffer_bits);
339 
340 	mutex_unlock(&crtc->drrs.mutex);
341 
342 	drm_modeset_unlock(&crtc->base.mutex);
343 
344 	return 0;
345 }
346 
347 DEFINE_SHOW_ATTRIBUTE(intel_drrs_debugfs_status);
348 
intel_drrs_debugfs_ctl_set(void * data,u64 val)349 static int intel_drrs_debugfs_ctl_set(void *data, u64 val)
350 {
351 	struct intel_crtc *crtc = data;
352 	struct drm_i915_private *i915 = to_i915(crtc->base.dev);
353 	struct intel_crtc_state *crtc_state;
354 	struct drm_crtc_commit *commit;
355 	int ret;
356 
357 	ret = drm_modeset_lock_single_interruptible(&crtc->base.mutex);
358 	if (ret)
359 		return ret;
360 
361 	crtc_state = to_intel_crtc_state(crtc->base.state);
362 
363 	if (!crtc_state->hw.active ||
364 	    !crtc_state->has_drrs)
365 		goto out;
366 
367 	commit = crtc_state->uapi.commit;
368 	if (commit) {
369 		ret = wait_for_completion_interruptible(&commit->hw_done);
370 		if (ret)
371 			goto out;
372 	}
373 
374 	drm_dbg(&i915->drm,
375 		"Manually %sactivating DRRS\n", val ? "" : "de");
376 
377 	if (val)
378 		intel_drrs_activate(crtc_state);
379 	else
380 		intel_drrs_deactivate(crtc_state);
381 
382 out:
383 	drm_modeset_unlock(&crtc->base.mutex);
384 
385 	return ret;
386 }
387 
388 DEFINE_DEBUGFS_ATTRIBUTE(intel_drrs_debugfs_ctl_fops,
389 			 NULL, intel_drrs_debugfs_ctl_set, "%llu\n");
390 
intel_drrs_crtc_debugfs_add(struct intel_crtc * crtc)391 void intel_drrs_crtc_debugfs_add(struct intel_crtc *crtc)
392 {
393 	debugfs_create_file("i915_drrs_status", 0444, crtc->base.debugfs_entry,
394 			    crtc, &intel_drrs_debugfs_status_fops);
395 
396 	debugfs_create_file_unsafe("i915_drrs_ctl", 0644, crtc->base.debugfs_entry,
397 				   crtc, &intel_drrs_debugfs_ctl_fops);
398 }
399 
intel_drrs_debugfs_type_show(struct seq_file * m,void * unused)400 static int intel_drrs_debugfs_type_show(struct seq_file *m, void *unused)
401 {
402 	struct intel_connector *connector = m->private;
403 
404 	seq_printf(m, "DRRS type: %s\n",
405 		   intel_drrs_type_str(intel_panel_drrs_type(connector)));
406 
407 	return 0;
408 }
409 
410 DEFINE_SHOW_ATTRIBUTE(intel_drrs_debugfs_type);
411 
intel_drrs_connector_debugfs_add(struct intel_connector * connector)412 void intel_drrs_connector_debugfs_add(struct intel_connector *connector)
413 {
414 	if (intel_panel_drrs_type(connector) == DRRS_TYPE_NONE)
415 		return;
416 
417 	debugfs_create_file("i915_drrs_type", 0444, connector->base.debugfs_entry,
418 			    connector, &intel_drrs_debugfs_type_fops);
419 }
420