xref: /linux/drivers/gpu/drm/i915/display/intel_load_detect.c (revision c532de5a67a70f8533d495f8f2aaa9a0491c3ad0)
1 // SPDX-License-Identifier: MIT
2 /*
3  * Copyright © 2023 Intel Corporation
4  */
5 
6 #include <drm/drm_atomic.h>
7 #include <drm/drm_atomic_helper.h>
8 #include <drm/drm_atomic_uapi.h>
9 
10 #include "i915_drv.h"
11 #include "intel_atomic.h"
12 #include "intel_crtc.h"
13 #include "intel_display_types.h"
14 #include "intel_load_detect.h"
15 
16 /* VESA 640x480x72Hz mode to set on the pipe */
17 static const struct drm_display_mode load_detect_mode = {
18 	DRM_MODE("640x480", DRM_MODE_TYPE_DEFAULT, 31500, 640, 664,
19 		 704, 832, 0, 480, 489, 491, 520, 0, DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC),
20 };
21 
22 static int intel_modeset_disable_planes(struct drm_atomic_state *state,
23 					struct drm_crtc *crtc)
24 {
25 	struct drm_plane *plane;
26 	struct drm_plane_state *plane_state;
27 	int ret, i;
28 
29 	ret = drm_atomic_add_affected_planes(state, crtc);
30 	if (ret)
31 		return ret;
32 
33 	for_each_new_plane_in_state(state, plane, plane_state, i) {
34 		if (plane_state->crtc != crtc)
35 			continue;
36 
37 		ret = drm_atomic_set_crtc_for_plane(plane_state, NULL);
38 		if (ret)
39 			return ret;
40 
41 		drm_atomic_set_fb_for_plane(plane_state, NULL);
42 	}
43 
44 	return 0;
45 }
46 
47 struct drm_atomic_state *
48 intel_load_detect_get_pipe(struct drm_connector *connector,
49 			   struct drm_modeset_acquire_ctx *ctx)
50 {
51 	struct intel_display *display = to_intel_display(connector->dev);
52 	struct intel_encoder *encoder =
53 		intel_attached_encoder(to_intel_connector(connector));
54 	struct intel_crtc *possible_crtc;
55 	struct intel_crtc *crtc = NULL;
56 	struct drm_mode_config *config = &display->drm->mode_config;
57 	struct drm_atomic_state *state = NULL, *restore_state = NULL;
58 	struct drm_connector_state *connector_state;
59 	struct intel_crtc_state *crtc_state;
60 	int ret;
61 
62 	drm_dbg_kms(display->drm, "[CONNECTOR:%d:%s], [ENCODER:%d:%s]\n",
63 		    connector->base.id, connector->name,
64 		    encoder->base.base.id, encoder->base.name);
65 
66 	drm_WARN_ON(display->drm, !drm_modeset_is_locked(&config->connection_mutex));
67 
68 	/*
69 	 * Algorithm gets a little messy:
70 	 *
71 	 *   - if the connector already has an assigned crtc, use it (but make
72 	 *     sure it's on first)
73 	 *
74 	 *   - try to find the first unused crtc that can drive this connector,
75 	 *     and use that if we find one
76 	 */
77 
78 	/* See if we already have a CRTC for this connector */
79 	if (connector->state->crtc) {
80 		crtc = to_intel_crtc(connector->state->crtc);
81 
82 		ret = drm_modeset_lock(&crtc->base.mutex, ctx);
83 		if (ret)
84 			goto fail;
85 
86 		/* Make sure the crtc and connector are running */
87 		goto found;
88 	}
89 
90 	/* Find an unused one (if possible) */
91 	for_each_intel_crtc(display->drm, possible_crtc) {
92 		if (!(encoder->base.possible_crtcs &
93 		      drm_crtc_mask(&possible_crtc->base)))
94 			continue;
95 
96 		ret = drm_modeset_lock(&possible_crtc->base.mutex, ctx);
97 		if (ret)
98 			goto fail;
99 
100 		if (possible_crtc->base.state->enable) {
101 			drm_modeset_unlock(&possible_crtc->base.mutex);
102 			continue;
103 		}
104 
105 		crtc = possible_crtc;
106 		break;
107 	}
108 
109 	/*
110 	 * If we didn't find an unused CRTC, don't use any.
111 	 */
112 	if (!crtc) {
113 		drm_dbg_kms(display->drm,
114 			    "no pipe available for load-detect\n");
115 		ret = -ENODEV;
116 		goto fail;
117 	}
118 
119 found:
120 	state = drm_atomic_state_alloc(display->drm);
121 	restore_state = drm_atomic_state_alloc(display->drm);
122 	if (!state || !restore_state) {
123 		ret = -ENOMEM;
124 		goto fail;
125 	}
126 
127 	state->acquire_ctx = ctx;
128 	to_intel_atomic_state(state)->internal = true;
129 
130 	restore_state->acquire_ctx = ctx;
131 	to_intel_atomic_state(restore_state)->internal = true;
132 
133 	connector_state = drm_atomic_get_connector_state(state, connector);
134 	if (IS_ERR(connector_state)) {
135 		ret = PTR_ERR(connector_state);
136 		goto fail;
137 	}
138 
139 	ret = drm_atomic_set_crtc_for_connector(connector_state, &crtc->base);
140 	if (ret)
141 		goto fail;
142 
143 	crtc_state = intel_atomic_get_crtc_state(state, crtc);
144 	if (IS_ERR(crtc_state)) {
145 		ret = PTR_ERR(crtc_state);
146 		goto fail;
147 	}
148 
149 	crtc_state->uapi.active = true;
150 
151 	ret = drm_atomic_set_mode_for_crtc(&crtc_state->uapi,
152 					   &load_detect_mode);
153 	if (ret)
154 		goto fail;
155 
156 	ret = intel_modeset_disable_planes(state, &crtc->base);
157 	if (ret)
158 		goto fail;
159 
160 	ret = PTR_ERR_OR_ZERO(drm_atomic_get_connector_state(restore_state, connector));
161 	if (!ret)
162 		ret = PTR_ERR_OR_ZERO(drm_atomic_get_crtc_state(restore_state, &crtc->base));
163 	if (!ret)
164 		ret = drm_atomic_add_affected_planes(restore_state, &crtc->base);
165 	if (ret) {
166 		drm_dbg_kms(display->drm,
167 			    "Failed to create a copy of old state to restore: %i\n",
168 			    ret);
169 		goto fail;
170 	}
171 
172 	ret = drm_atomic_commit(state);
173 	if (ret) {
174 		drm_dbg_kms(display->drm,
175 			    "failed to set mode on load-detect pipe\n");
176 		goto fail;
177 	}
178 
179 	drm_atomic_state_put(state);
180 
181 	/* let the connector get through one full cycle before testing */
182 	intel_crtc_wait_for_next_vblank(crtc);
183 
184 	return restore_state;
185 
186 fail:
187 	if (state) {
188 		drm_atomic_state_put(state);
189 		state = NULL;
190 	}
191 	if (restore_state) {
192 		drm_atomic_state_put(restore_state);
193 		restore_state = NULL;
194 	}
195 
196 	if (ret == -EDEADLK)
197 		return ERR_PTR(ret);
198 
199 	return NULL;
200 }
201 
202 void intel_load_detect_release_pipe(struct drm_connector *connector,
203 				    struct drm_atomic_state *state,
204 				    struct drm_modeset_acquire_ctx *ctx)
205 {
206 	struct intel_display *display = to_intel_display(connector->dev);
207 	struct intel_encoder *intel_encoder =
208 		intel_attached_encoder(to_intel_connector(connector));
209 	struct drm_encoder *encoder = &intel_encoder->base;
210 	int ret;
211 
212 	drm_dbg_kms(display->drm, "[CONNECTOR:%d:%s], [ENCODER:%d:%s]\n",
213 		    connector->base.id, connector->name,
214 		    encoder->base.id, encoder->name);
215 
216 	if (IS_ERR_OR_NULL(state))
217 		return;
218 
219 	ret = drm_atomic_helper_commit_duplicated_state(state, ctx);
220 	if (ret)
221 		drm_dbg_kms(display->drm,
222 			    "Couldn't release load detect pipe: %i\n", ret);
223 	drm_atomic_state_put(state);
224 }
225