1// SPDX-License-Identifier: MIT
2/*
3 * Copyright © 2020 Intel Corporation
4 */
5#include <linux/kernel.h>
6#include <linux/pm_qos.h>
7#include <linux/slab.h>
8
9#include <drm/drm_atomic_helper.h>
10#include <drm/drm_fourcc.h>
11#include <drm/drm_plane.h>
12#include <drm/drm_vblank_work.h>
13
14#include "i915_vgpu.h"
15#include "i9xx_plane.h"
16#include "icl_dsi.h"
17#include "intel_atomic.h"
18#include "intel_atomic_plane.h"
19#include "intel_color.h"
20#include "intel_crtc.h"
21#include "intel_cursor.h"
22#include "intel_display_debugfs.h"
23#include "intel_display_irq.h"
24#include "intel_display_trace.h"
25#include "intel_display_types.h"
26#include "intel_drrs.h"
27#include "intel_dsb.h"
28#include "intel_dsi.h"
29#include "intel_fifo_underrun.h"
30#include "intel_pipe_crc.h"
31#include "intel_psr.h"
32#include "intel_sprite.h"
33#include "intel_vblank.h"
34#include "intel_vrr.h"
35#include "skl_universal_plane.h"
36
37static void assert_vblank_disabled(struct drm_crtc *crtc)
38{
39 struct drm_i915_private *i915 = to_i915(dev: crtc->dev);
40
41 if (I915_STATE_WARN(i915, drm_crtc_vblank_get(crtc) == 0,
42 "[CRTC:%d:%s] vblank assertion failure (expected off, current on)\n",
43 crtc->base.id, crtc->name))
44 drm_crtc_vblank_put(crtc);
45}
46
47struct intel_crtc *intel_first_crtc(struct drm_i915_private *i915)
48{
49 return to_intel_crtc(drm_crtc_from_index(&i915->drm, 0));
50}
51
52struct intel_crtc *intel_crtc_for_pipe(struct drm_i915_private *i915,
53 enum pipe pipe)
54{
55 struct intel_crtc *crtc;
56
57 for_each_intel_crtc(&i915->drm, crtc) {
58 if (crtc->pipe == pipe)
59 return crtc;
60 }
61
62 return NULL;
63}
64
65void intel_crtc_wait_for_next_vblank(struct intel_crtc *crtc)
66{
67 drm_crtc_wait_one_vblank(crtc: &crtc->base);
68}
69
70void intel_wait_for_vblank_if_active(struct drm_i915_private *i915,
71 enum pipe pipe)
72{
73 struct intel_crtc *crtc = intel_crtc_for_pipe(i915, pipe);
74
75 if (crtc->active)
76 intel_crtc_wait_for_next_vblank(crtc);
77}
78
79u32 intel_crtc_get_vblank_counter(struct intel_crtc *crtc)
80{
81 struct drm_device *dev = crtc->base.dev;
82 struct drm_vblank_crtc *vblank = &dev->vblank[drm_crtc_index(crtc: &crtc->base)];
83
84 if (!crtc->active)
85 return 0;
86
87 if (!vblank->max_vblank_count)
88 return (u32)drm_crtc_accurate_vblank_count(crtc: &crtc->base);
89
90 return crtc->base.funcs->get_vblank_counter(&crtc->base);
91}
92
93u32 intel_crtc_max_vblank_count(const struct intel_crtc_state *crtc_state)
94{
95 struct drm_i915_private *dev_priv = to_i915(dev: crtc_state->uapi.crtc->dev);
96
97 /*
98 * From Gen 11, In case of dsi cmd mode, frame counter wouldnt
99 * have updated at the beginning of TE, if we want to use
100 * the hw counter, then we would find it updated in only
101 * the next TE, hence switching to sw counter.
102 */
103 if (crtc_state->mode_flags & (I915_MODE_FLAG_DSI_USE_TE0 |
104 I915_MODE_FLAG_DSI_USE_TE1))
105 return 0;
106
107 /*
108 * On i965gm the hardware frame counter reads
109 * zero when the TV encoder is enabled :(
110 */
111 if (IS_I965GM(dev_priv) &&
112 (crtc_state->output_types & BIT(INTEL_OUTPUT_TVOUT)))
113 return 0;
114
115 if (DISPLAY_VER(dev_priv) >= 5 || IS_G4X(dev_priv))
116 return 0xffffffff; /* full 32 bit counter */
117 else if (DISPLAY_VER(dev_priv) >= 3)
118 return 0xffffff; /* only 24 bits of frame count */
119 else
120 return 0; /* Gen2 doesn't have a hardware frame counter */
121}
122
123void intel_crtc_vblank_on(const struct intel_crtc_state *crtc_state)
124{
125 struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
126
127 assert_vblank_disabled(crtc: &crtc->base);
128 drm_crtc_set_max_vblank_count(crtc: &crtc->base,
129 max_vblank_count: intel_crtc_max_vblank_count(crtc_state));
130 drm_crtc_vblank_on(crtc: &crtc->base);
131
132 /*
133 * Should really happen exactly when we enable the pipe
134 * but we want the frame counters in the trace, and that
135 * requires vblank support on some platforms/outputs.
136 */
137 trace_intel_pipe_enable(crtc);
138}
139
140void intel_crtc_vblank_off(const struct intel_crtc_state *crtc_state)
141{
142 struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
143
144 /*
145 * Should really happen exactly when we disable the pipe
146 * but we want the frame counters in the trace, and that
147 * requires vblank support on some platforms/outputs.
148 */
149 trace_intel_pipe_disable(crtc);
150
151 drm_crtc_vblank_off(crtc: &crtc->base);
152 assert_vblank_disabled(crtc: &crtc->base);
153}
154
155struct intel_crtc_state *intel_crtc_state_alloc(struct intel_crtc *crtc)
156{
157 struct intel_crtc_state *crtc_state;
158
159 crtc_state = kmalloc(size: sizeof(*crtc_state), GFP_KERNEL);
160
161 if (crtc_state)
162 intel_crtc_state_reset(crtc_state, crtc);
163
164 return crtc_state;
165}
166
167void intel_crtc_state_reset(struct intel_crtc_state *crtc_state,
168 struct intel_crtc *crtc)
169{
170 memset(crtc_state, 0, sizeof(*crtc_state));
171
172 __drm_atomic_helper_crtc_state_reset(state: &crtc_state->uapi, crtc: &crtc->base);
173
174 crtc_state->cpu_transcoder = INVALID_TRANSCODER;
175 crtc_state->master_transcoder = INVALID_TRANSCODER;
176 crtc_state->hsw_workaround_pipe = INVALID_PIPE;
177 crtc_state->scaler_state.scaler_id = -1;
178 crtc_state->mst_master_transcoder = INVALID_TRANSCODER;
179 crtc_state->max_link_bpp_x16 = INT_MAX;
180}
181
182static struct intel_crtc *intel_crtc_alloc(void)
183{
184 struct intel_crtc_state *crtc_state;
185 struct intel_crtc *crtc;
186
187 crtc = kzalloc(size: sizeof(*crtc), GFP_KERNEL);
188 if (!crtc)
189 return ERR_PTR(error: -ENOMEM);
190
191 crtc_state = intel_crtc_state_alloc(crtc);
192 if (!crtc_state) {
193 kfree(objp: crtc);
194 return ERR_PTR(error: -ENOMEM);
195 }
196
197 crtc->base.state = &crtc_state->uapi;
198 crtc->config = crtc_state;
199
200 return crtc;
201}
202
203static void intel_crtc_free(struct intel_crtc *crtc)
204{
205 intel_crtc_destroy_state(crtc: &crtc->base, state: crtc->base.state);
206 kfree(objp: crtc);
207}
208
209static void intel_crtc_destroy(struct drm_crtc *_crtc)
210{
211 struct intel_crtc *crtc = to_intel_crtc(_crtc);
212
213 cpu_latency_qos_remove_request(req: &crtc->vblank_pm_qos);
214
215 drm_crtc_cleanup(crtc: &crtc->base);
216 kfree(objp: crtc);
217}
218
219static int intel_crtc_late_register(struct drm_crtc *crtc)
220{
221 intel_crtc_debugfs_add(to_intel_crtc(crtc));
222 return 0;
223}
224
225#define INTEL_CRTC_FUNCS \
226 .set_config = drm_atomic_helper_set_config, \
227 .destroy = intel_crtc_destroy, \
228 .page_flip = drm_atomic_helper_page_flip, \
229 .atomic_duplicate_state = intel_crtc_duplicate_state, \
230 .atomic_destroy_state = intel_crtc_destroy_state, \
231 .set_crc_source = intel_crtc_set_crc_source, \
232 .verify_crc_source = intel_crtc_verify_crc_source, \
233 .get_crc_sources = intel_crtc_get_crc_sources, \
234 .late_register = intel_crtc_late_register
235
236static const struct drm_crtc_funcs bdw_crtc_funcs = {
237 INTEL_CRTC_FUNCS,
238
239 .get_vblank_counter = g4x_get_vblank_counter,
240 .enable_vblank = bdw_enable_vblank,
241 .disable_vblank = bdw_disable_vblank,
242 .get_vblank_timestamp = intel_crtc_get_vblank_timestamp,
243};
244
245static const struct drm_crtc_funcs ilk_crtc_funcs = {
246 INTEL_CRTC_FUNCS,
247
248 .get_vblank_counter = g4x_get_vblank_counter,
249 .enable_vblank = ilk_enable_vblank,
250 .disable_vblank = ilk_disable_vblank,
251 .get_vblank_timestamp = intel_crtc_get_vblank_timestamp,
252};
253
254static const struct drm_crtc_funcs g4x_crtc_funcs = {
255 INTEL_CRTC_FUNCS,
256
257 .get_vblank_counter = g4x_get_vblank_counter,
258 .enable_vblank = i965_enable_vblank,
259 .disable_vblank = i965_disable_vblank,
260 .get_vblank_timestamp = intel_crtc_get_vblank_timestamp,
261};
262
263static const struct drm_crtc_funcs i965_crtc_funcs = {
264 INTEL_CRTC_FUNCS,
265
266 .get_vblank_counter = i915_get_vblank_counter,
267 .enable_vblank = i965_enable_vblank,
268 .disable_vblank = i965_disable_vblank,
269 .get_vblank_timestamp = intel_crtc_get_vblank_timestamp,
270};
271
272static const struct drm_crtc_funcs i915gm_crtc_funcs = {
273 INTEL_CRTC_FUNCS,
274
275 .get_vblank_counter = i915_get_vblank_counter,
276 .enable_vblank = i915gm_enable_vblank,
277 .disable_vblank = i915gm_disable_vblank,
278 .get_vblank_timestamp = intel_crtc_get_vblank_timestamp,
279};
280
281static const struct drm_crtc_funcs i915_crtc_funcs = {
282 INTEL_CRTC_FUNCS,
283
284 .get_vblank_counter = i915_get_vblank_counter,
285 .enable_vblank = i8xx_enable_vblank,
286 .disable_vblank = i8xx_disable_vblank,
287 .get_vblank_timestamp = intel_crtc_get_vblank_timestamp,
288};
289
290static const struct drm_crtc_funcs i8xx_crtc_funcs = {
291 INTEL_CRTC_FUNCS,
292
293 /* no hw vblank counter */
294 .enable_vblank = i8xx_enable_vblank,
295 .disable_vblank = i8xx_disable_vblank,
296 .get_vblank_timestamp = intel_crtc_get_vblank_timestamp,
297};
298
299int intel_crtc_init(struct drm_i915_private *dev_priv, enum pipe pipe)
300{
301 struct intel_plane *primary, *cursor;
302 const struct drm_crtc_funcs *funcs;
303 struct intel_crtc *crtc;
304 int sprite, ret;
305
306 crtc = intel_crtc_alloc();
307 if (IS_ERR(ptr: crtc))
308 return PTR_ERR(ptr: crtc);
309
310 crtc->pipe = pipe;
311 crtc->num_scalers = DISPLAY_RUNTIME_INFO(dev_priv)->num_scalers[pipe];
312
313 if (DISPLAY_VER(dev_priv) >= 9)
314 primary = skl_universal_plane_create(dev_priv, pipe,
315 plane_id: PLANE_PRIMARY);
316 else
317 primary = intel_primary_plane_create(dev_priv, pipe);
318 if (IS_ERR(ptr: primary)) {
319 ret = PTR_ERR(ptr: primary);
320 goto fail;
321 }
322 crtc->plane_ids_mask |= BIT(primary->id);
323
324 intel_init_fifo_underrun_reporting(i915: dev_priv, crtc, enable: false);
325
326 for_each_sprite(dev_priv, pipe, sprite) {
327 struct intel_plane *plane;
328
329 if (DISPLAY_VER(dev_priv) >= 9)
330 plane = skl_universal_plane_create(dev_priv, pipe,
331 plane_id: PLANE_SPRITE0 + sprite);
332 else
333 plane = intel_sprite_plane_create(dev_priv, pipe, plane: sprite);
334 if (IS_ERR(ptr: plane)) {
335 ret = PTR_ERR(ptr: plane);
336 goto fail;
337 }
338 crtc->plane_ids_mask |= BIT(plane->id);
339 }
340
341 cursor = intel_cursor_plane_create(dev_priv, pipe);
342 if (IS_ERR(ptr: cursor)) {
343 ret = PTR_ERR(ptr: cursor);
344 goto fail;
345 }
346 crtc->plane_ids_mask |= BIT(cursor->id);
347
348 if (HAS_GMCH(dev_priv)) {
349 if (IS_CHERRYVIEW(dev_priv) ||
350 IS_VALLEYVIEW(dev_priv) || IS_G4X(dev_priv))
351 funcs = &g4x_crtc_funcs;
352 else if (DISPLAY_VER(dev_priv) == 4)
353 funcs = &i965_crtc_funcs;
354 else if (IS_I945GM(dev_priv) || IS_I915GM(dev_priv))
355 funcs = &i915gm_crtc_funcs;
356 else if (DISPLAY_VER(dev_priv) == 3)
357 funcs = &i915_crtc_funcs;
358 else
359 funcs = &i8xx_crtc_funcs;
360 } else {
361 if (DISPLAY_VER(dev_priv) >= 8)
362 funcs = &bdw_crtc_funcs;
363 else
364 funcs = &ilk_crtc_funcs;
365 }
366
367 ret = drm_crtc_init_with_planes(dev: &dev_priv->drm, crtc: &crtc->base,
368 primary: &primary->base, cursor: &cursor->base,
369 funcs, name: "pipe %c", pipe_name(pipe));
370 if (ret)
371 goto fail;
372
373 if (DISPLAY_VER(dev_priv) >= 11)
374 drm_crtc_create_scaling_filter_property(crtc: &crtc->base,
375 BIT(DRM_SCALING_FILTER_DEFAULT) |
376 BIT(DRM_SCALING_FILTER_NEAREST_NEIGHBOR));
377
378 intel_color_crtc_init(crtc);
379 intel_drrs_crtc_init(crtc);
380 intel_crtc_crc_init(crtc);
381
382 cpu_latency_qos_add_request(req: &crtc->vblank_pm_qos, PM_QOS_DEFAULT_VALUE);
383
384 drm_WARN_ON(&dev_priv->drm, drm_crtc_index(&crtc->base) != crtc->pipe);
385
386 return 0;
387
388fail:
389 intel_crtc_free(crtc);
390
391 return ret;
392}
393
394static bool intel_crtc_needs_vblank_work(const struct intel_crtc_state *crtc_state)
395{
396 return crtc_state->hw.active &&
397 !intel_crtc_needs_modeset(crtc_state) &&
398 !crtc_state->preload_luts &&
399 intel_crtc_needs_color_update(crtc_state) &&
400 !intel_color_uses_dsb(crtc_state);
401}
402
403static void intel_crtc_vblank_work(struct kthread_work *base)
404{
405 struct drm_vblank_work *work = to_drm_vblank_work(base);
406 struct intel_crtc_state *crtc_state =
407 container_of(work, typeof(*crtc_state), vblank_work);
408 struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
409
410 trace_intel_crtc_vblank_work_start(crtc);
411
412 intel_color_load_luts(crtc_state);
413
414 if (crtc_state->uapi.event) {
415 spin_lock_irq(lock: &crtc->base.dev->event_lock);
416 drm_crtc_send_vblank_event(crtc: &crtc->base, e: crtc_state->uapi.event);
417 crtc_state->uapi.event = NULL;
418 spin_unlock_irq(lock: &crtc->base.dev->event_lock);
419 }
420
421 trace_intel_crtc_vblank_work_end(crtc);
422}
423
424static void intel_crtc_vblank_work_init(struct intel_crtc_state *crtc_state)
425{
426 struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
427
428 drm_vblank_work_init(work: &crtc_state->vblank_work, crtc: &crtc->base,
429 func: intel_crtc_vblank_work);
430 /*
431 * Interrupt latency is critical for getting the vblank
432 * work executed as early as possible during the vblank.
433 */
434 cpu_latency_qos_update_request(req: &crtc->vblank_pm_qos, new_value: 0);
435}
436
437void intel_wait_for_vblank_workers(struct intel_atomic_state *state)
438{
439 struct intel_crtc_state *crtc_state;
440 struct intel_crtc *crtc;
441 int i;
442
443 for_each_new_intel_crtc_in_state(state, crtc, crtc_state, i) {
444 if (!intel_crtc_needs_vblank_work(crtc_state))
445 continue;
446
447 drm_vblank_work_flush(work: &crtc_state->vblank_work);
448 cpu_latency_qos_update_request(req: &crtc->vblank_pm_qos,
449 PM_QOS_DEFAULT_VALUE);
450 }
451}
452
453int intel_usecs_to_scanlines(const struct drm_display_mode *adjusted_mode,
454 int usecs)
455{
456 /* paranoia */
457 if (!adjusted_mode->crtc_htotal)
458 return 1;
459
460 return DIV_ROUND_UP(usecs * adjusted_mode->crtc_clock,
461 1000 * adjusted_mode->crtc_htotal);
462}
463
464/**
465 * intel_pipe_update_start() - start update of a set of display registers
466 * @state: the atomic state
467 * @crtc: the crtc
468 *
469 * Mark the start of an update to pipe registers that should be updated
470 * atomically regarding vblank. If the next vblank will happens within
471 * the next 100 us, this function waits until the vblank passes.
472 *
473 * After a successful call to this function, interrupts will be disabled
474 * until a subsequent call to intel_pipe_update_end(). That is done to
475 * avoid random delays.
476 */
477void intel_pipe_update_start(struct intel_atomic_state *state,
478 struct intel_crtc *crtc)
479{
480 struct drm_i915_private *dev_priv = to_i915(dev: crtc->base.dev);
481 const struct intel_crtc_state *old_crtc_state =
482 intel_atomic_get_old_crtc_state(state, crtc);
483 struct intel_crtc_state *new_crtc_state =
484 intel_atomic_get_new_crtc_state(state, crtc);
485 struct intel_vblank_evade_ctx evade;
486 int scanline;
487
488 intel_psr_lock(crtc_state: new_crtc_state);
489
490 if (new_crtc_state->do_async_flip) {
491 spin_lock_irq(lock: &crtc->base.dev->event_lock);
492 /* arm the event for the flip done irq handler */
493 crtc->flip_done_event = new_crtc_state->uapi.event;
494 spin_unlock_irq(lock: &crtc->base.dev->event_lock);
495
496 new_crtc_state->uapi.event = NULL;
497 return;
498 }
499
500 if (intel_crtc_needs_vblank_work(crtc_state: new_crtc_state))
501 intel_crtc_vblank_work_init(crtc_state: new_crtc_state);
502
503 intel_vblank_evade_init(old_crtc_state, new_crtc_state, evade: &evade);
504
505 if (drm_WARN_ON(&dev_priv->drm, drm_crtc_vblank_get(&crtc->base)))
506 goto irq_disable;
507
508 /*
509 * Wait for psr to idle out after enabling the VBL interrupts
510 * VBL interrupts will start the PSR exit and prevent a PSR
511 * re-entry as well.
512 */
513 intel_psr_wait_for_idle_locked(new_crtc_state);
514
515 local_irq_disable();
516
517 crtc->debug.min_vbl = evade.min;
518 crtc->debug.max_vbl = evade.max;
519 trace_intel_pipe_update_start(crtc);
520
521 scanline = intel_vblank_evade(evade: &evade);
522
523 drm_crtc_vblank_put(crtc: &crtc->base);
524
525 crtc->debug.scanline_start = scanline;
526 crtc->debug.start_vbl_time = ktime_get();
527 crtc->debug.start_vbl_count = intel_crtc_get_vblank_counter(crtc);
528
529 trace_intel_pipe_update_vblank_evaded(crtc);
530 return;
531
532irq_disable:
533 local_irq_disable();
534}
535
536#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_VBLANK_EVADE)
537static void dbg_vblank_evade(struct intel_crtc *crtc, ktime_t end)
538{
539 u64 delta = ktime_to_ns(ktime_sub(end, crtc->debug.start_vbl_time));
540 unsigned int h;
541
542 h = ilog2(delta >> 9);
543 if (h >= ARRAY_SIZE(crtc->debug.vbl.times))
544 h = ARRAY_SIZE(crtc->debug.vbl.times) - 1;
545 crtc->debug.vbl.times[h]++;
546
547 crtc->debug.vbl.sum += delta;
548 if (!crtc->debug.vbl.min || delta < crtc->debug.vbl.min)
549 crtc->debug.vbl.min = delta;
550 if (delta > crtc->debug.vbl.max)
551 crtc->debug.vbl.max = delta;
552
553 if (delta > 1000 * VBLANK_EVASION_TIME_US) {
554 drm_dbg_kms(crtc->base.dev,
555 "Atomic update on pipe (%c) took %lld us, max time under evasion is %u us\n",
556 pipe_name(crtc->pipe),
557 div_u64(delta, 1000),
558 VBLANK_EVASION_TIME_US);
559 crtc->debug.vbl.over++;
560 }
561}
562#else
563static void dbg_vblank_evade(struct intel_crtc *crtc, ktime_t end) {}
564#endif
565
566/**
567 * intel_pipe_update_end() - end update of a set of display registers
568 * @state: the atomic state
569 * @crtc: the crtc
570 *
571 * Mark the end of an update started with intel_pipe_update_start(). This
572 * re-enables interrupts and verifies the update was actually completed
573 * before a vblank.
574 */
575void intel_pipe_update_end(struct intel_atomic_state *state,
576 struct intel_crtc *crtc)
577{
578 struct intel_crtc_state *new_crtc_state =
579 intel_atomic_get_new_crtc_state(state, crtc);
580 enum pipe pipe = crtc->pipe;
581 int scanline_end = intel_get_crtc_scanline(crtc);
582 u32 end_vbl_count = intel_crtc_get_vblank_counter(crtc);
583 ktime_t end_vbl_time = ktime_get();
584 struct drm_i915_private *dev_priv = to_i915(dev: crtc->base.dev);
585
586 if (new_crtc_state->do_async_flip)
587 goto out;
588
589 trace_intel_pipe_update_end(crtc, frame: end_vbl_count, scanline_end);
590
591 /*
592 * Incase of mipi dsi command mode, we need to set frame update
593 * request for every commit.
594 */
595 if (DISPLAY_VER(dev_priv) >= 11 &&
596 intel_crtc_has_type(crtc_state: new_crtc_state, type: INTEL_OUTPUT_DSI))
597 icl_dsi_frame_update(crtc_state: new_crtc_state);
598
599 /* We're still in the vblank-evade critical section, this can't race.
600 * Would be slightly nice to just grab the vblank count and arm the
601 * event outside of the critical section - the spinlock might spin for a
602 * while ... */
603 if (intel_crtc_needs_vblank_work(crtc_state: new_crtc_state)) {
604 drm_vblank_work_schedule(work: &new_crtc_state->vblank_work,
605 count: drm_crtc_accurate_vblank_count(crtc: &crtc->base) + 1,
606 nextonmiss: false);
607 } else if (new_crtc_state->uapi.event) {
608 drm_WARN_ON(&dev_priv->drm,
609 drm_crtc_vblank_get(&crtc->base) != 0);
610
611 spin_lock(lock: &crtc->base.dev->event_lock);
612 drm_crtc_arm_vblank_event(crtc: &crtc->base,
613 e: new_crtc_state->uapi.event);
614 spin_unlock(lock: &crtc->base.dev->event_lock);
615
616 new_crtc_state->uapi.event = NULL;
617 }
618
619 /*
620 * Send VRR Push to terminate Vblank. If we are already in vblank
621 * this has to be done _after_ sampling the frame counter, as
622 * otherwise the push would immediately terminate the vblank and
623 * the sampled frame counter would correspond to the next frame
624 * instead of the current frame.
625 *
626 * There is a tiny race here (iff vblank evasion failed us) where
627 * we might sample the frame counter just before vmax vblank start
628 * but the push would be sent just after it. That would cause the
629 * push to affect the next frame instead of the current frame,
630 * which would cause the next frame to terminate already at vmin
631 * vblank start instead of vmax vblank start.
632 */
633 intel_vrr_send_push(crtc_state: new_crtc_state);
634
635 local_irq_enable();
636
637 if (intel_vgpu_active(i915: dev_priv))
638 goto out;
639
640 if (crtc->debug.start_vbl_count &&
641 crtc->debug.start_vbl_count != end_vbl_count) {
642 drm_err(&dev_priv->drm,
643 "Atomic update failure on pipe %c (start=%u end=%u) time %lld us, min %d, max %d, scanline start %d, end %d\n",
644 pipe_name(pipe), crtc->debug.start_vbl_count,
645 end_vbl_count,
646 ktime_us_delta(end_vbl_time,
647 crtc->debug.start_vbl_time),
648 crtc->debug.min_vbl, crtc->debug.max_vbl,
649 crtc->debug.scanline_start, scanline_end);
650 }
651
652 dbg_vblank_evade(crtc, end: end_vbl_time);
653
654out:
655 intel_psr_unlock(crtc_state: new_crtc_state);
656}
657

source code of linux/drivers/gpu/drm/i915/display/intel_crtc.c