xref: /linux/drivers/gpu/drm/i915/display/intel_vrr.c (revision bf62221e9d0e1e4ba50ab2b331a0008c15de97be)
1 // SPDX-License-Identifier: MIT
2 /*
3  * Copyright © 2020 Intel Corporation
4  *
5  */
6 
7 #include "i915_drv.h"
8 #include "intel_de.h"
9 #include "intel_display_types.h"
10 #include "intel_vrr.h"
11 
12 bool intel_vrr_is_capable(struct drm_connector *connector)
13 {
14 	struct intel_dp *intel_dp;
15 	const struct drm_display_info *info = &connector->display_info;
16 	struct drm_i915_private *i915 = to_i915(connector->dev);
17 
18 	if (connector->connector_type != DRM_MODE_CONNECTOR_eDP &&
19 	    connector->connector_type != DRM_MODE_CONNECTOR_DisplayPort)
20 		return false;
21 
22 	intel_dp = intel_attached_dp(to_intel_connector(connector));
23 	/*
24 	 * DP Sink is capable of VRR video timings if
25 	 * Ignore MSA bit is set in DPCD.
26 	 * EDID monitor range also should be atleast 10 for reasonable
27 	 * Adaptive Sync or Variable Refresh Rate end user experience.
28 	 */
29 	return HAS_VRR(i915) &&
30 		drm_dp_sink_can_do_video_without_timing_msa(intel_dp->dpcd) &&
31 		info->monitor_range.max_vfreq - info->monitor_range.min_vfreq > 10;
32 }
33 
34 void
35 intel_vrr_check_modeset(struct intel_atomic_state *state)
36 {
37 	int i;
38 	struct intel_crtc_state *old_crtc_state, *new_crtc_state;
39 	struct intel_crtc *crtc;
40 
41 	for_each_oldnew_intel_crtc_in_state(state, crtc, old_crtc_state,
42 					    new_crtc_state, i) {
43 		if (new_crtc_state->uapi.vrr_enabled !=
44 		    old_crtc_state->uapi.vrr_enabled)
45 			new_crtc_state->uapi.mode_changed = true;
46 	}
47 }
48 
49 /*
50  * Without VRR registers get latched at:
51  *  vblank_start
52  *
53  * With VRR the earliest registers can get latched is:
54  *  intel_vrr_vmin_vblank_start(), which if we want to maintain
55  *  the correct min vtotal is >=vblank_start+1
56  *
57  * The latest point registers can get latched is the vmax decision boundary:
58  *  intel_vrr_vmax_vblank_start()
59  *
60  * Between those two points the vblank exit starts (and hence registers get
61  * latched) ASAP after a push is sent.
62  *
63  * framestart_delay is programmable 0-3.
64  */
65 static int intel_vrr_vblank_exit_length(const struct intel_crtc_state *crtc_state)
66 {
67 	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
68 	struct drm_i915_private *i915 = to_i915(crtc->base.dev);
69 
70 	/* The hw imposes the extra scanline before frame start */
71 	return crtc_state->vrr.pipeline_full + i915->framestart_delay + 1;
72 }
73 
74 int intel_vrr_vmin_vblank_start(const struct intel_crtc_state *crtc_state)
75 {
76 	/* Min vblank actually determined by flipline that is always >=vmin+1 */
77 	return crtc_state->vrr.vmin + 1 - intel_vrr_vblank_exit_length(crtc_state);
78 }
79 
80 int intel_vrr_vmax_vblank_start(const struct intel_crtc_state *crtc_state)
81 {
82 	return crtc_state->vrr.vmax - intel_vrr_vblank_exit_length(crtc_state);
83 }
84 
85 void
86 intel_vrr_compute_config(struct intel_crtc_state *crtc_state,
87 			 struct drm_connector_state *conn_state)
88 {
89 	struct intel_connector *connector =
90 		to_intel_connector(conn_state->connector);
91 	struct drm_display_mode *adjusted_mode = &crtc_state->hw.adjusted_mode;
92 	const struct drm_display_info *info = &connector->base.display_info;
93 	int vmin, vmax;
94 
95 	if (!intel_vrr_is_capable(&connector->base))
96 		return;
97 
98 	if (adjusted_mode->flags & DRM_MODE_FLAG_INTERLACE)
99 		return;
100 
101 	if (!crtc_state->uapi.vrr_enabled)
102 		return;
103 
104 	vmin = DIV_ROUND_UP(adjusted_mode->crtc_clock * 1000,
105 			    adjusted_mode->crtc_htotal * info->monitor_range.max_vfreq);
106 	vmax = adjusted_mode->crtc_clock * 1000 /
107 		(adjusted_mode->crtc_htotal * info->monitor_range.min_vfreq);
108 
109 	vmin = max_t(int, vmin, adjusted_mode->crtc_vtotal);
110 	vmax = max_t(int, vmax, adjusted_mode->crtc_vtotal);
111 
112 	if (vmin >= vmax)
113 		return;
114 
115 	/*
116 	 * flipline determines the min vblank length the hardware will
117 	 * generate, and flipline>=vmin+1, hence we reduce vmin by one
118 	 * to make sure we can get the actual min vblank length.
119 	 */
120 	crtc_state->vrr.vmin = vmin - 1;
121 	crtc_state->vrr.vmax = vmax;
122 	crtc_state->vrr.enable = true;
123 
124 	crtc_state->vrr.flipline = crtc_state->vrr.vmin + 1;
125 
126 	/*
127 	 * FIXME: s/4/framestart_delay+1/ to get consistent
128 	 * earliest/latest points for register latching regardless
129 	 * of the framestart_delay used?
130 	 *
131 	 * FIXME: this really needs the extra scanline to provide consistent
132 	 * behaviour for all framestart_delay values. Otherwise with
133 	 * framestart_delay==3 we will end up extending the min vblank by
134 	 * one extra line.
135 	 */
136 	crtc_state->vrr.pipeline_full =
137 		min(255, crtc_state->vrr.vmin - adjusted_mode->crtc_vdisplay - 4 - 1);
138 
139 	crtc_state->mode_flags |= I915_MODE_FLAG_VRR;
140 }
141 
142 void intel_vrr_enable(struct intel_encoder *encoder,
143 		      const struct intel_crtc_state *crtc_state)
144 {
145 	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
146 	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
147 	u32 trans_vrr_ctl;
148 
149 	if (!crtc_state->vrr.enable)
150 		return;
151 
152 	trans_vrr_ctl = VRR_CTL_VRR_ENABLE |
153 		VRR_CTL_IGN_MAX_SHIFT | VRR_CTL_FLIP_LINE_EN |
154 		VRR_CTL_PIPELINE_FULL(crtc_state->vrr.pipeline_full) |
155 		VRR_CTL_PIPELINE_FULL_OVERRIDE;
156 
157 	intel_de_write(dev_priv, TRANS_VRR_VMIN(cpu_transcoder), crtc_state->vrr.vmin - 1);
158 	intel_de_write(dev_priv, TRANS_VRR_VMAX(cpu_transcoder), crtc_state->vrr.vmax - 1);
159 	intel_de_write(dev_priv, TRANS_VRR_CTL(cpu_transcoder), trans_vrr_ctl);
160 	intel_de_write(dev_priv, TRANS_VRR_FLIPLINE(cpu_transcoder), crtc_state->vrr.flipline - 1);
161 	intel_de_write(dev_priv, TRANS_PUSH(cpu_transcoder), TRANS_PUSH_EN);
162 }
163 
164 void intel_vrr_send_push(const struct intel_crtc_state *crtc_state)
165 {
166 	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
167 	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
168 	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
169 
170 	if (!crtc_state->vrr.enable)
171 		return;
172 
173 	intel_de_write(dev_priv, TRANS_PUSH(cpu_transcoder),
174 		       TRANS_PUSH_EN | TRANS_PUSH_SEND);
175 }
176 
177 void intel_vrr_disable(const struct intel_crtc_state *old_crtc_state)
178 {
179 	struct intel_crtc *crtc = to_intel_crtc(old_crtc_state->uapi.crtc);
180 	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
181 	enum transcoder cpu_transcoder = old_crtc_state->cpu_transcoder;
182 
183 	if (!old_crtc_state->vrr.enable)
184 		return;
185 
186 	intel_de_write(dev_priv, TRANS_VRR_CTL(cpu_transcoder), 0);
187 	intel_de_write(dev_priv, TRANS_PUSH(cpu_transcoder), 0);
188 }
189 
190 void intel_vrr_get_config(struct intel_crtc *crtc,
191 			  struct intel_crtc_state *crtc_state)
192 {
193 	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
194 	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
195 	u32 trans_vrr_ctl;
196 
197 	trans_vrr_ctl = intel_de_read(dev_priv, TRANS_VRR_CTL(cpu_transcoder));
198 	crtc_state->vrr.enable = trans_vrr_ctl & VRR_CTL_VRR_ENABLE;
199 	if (!crtc_state->vrr.enable)
200 		return;
201 
202 	if (trans_vrr_ctl & VRR_CTL_PIPELINE_FULL_OVERRIDE)
203 		crtc_state->vrr.pipeline_full = REG_FIELD_GET(VRR_CTL_PIPELINE_FULL_MASK, trans_vrr_ctl);
204 	if (trans_vrr_ctl & VRR_CTL_FLIP_LINE_EN)
205 		crtc_state->vrr.flipline = intel_de_read(dev_priv, TRANS_VRR_FLIPLINE(cpu_transcoder)) + 1;
206 	crtc_state->vrr.vmax = intel_de_read(dev_priv, TRANS_VRR_VMAX(cpu_transcoder)) + 1;
207 	crtc_state->vrr.vmin = intel_de_read(dev_priv, TRANS_VRR_VMIN(cpu_transcoder)) + 1;
208 
209 	crtc_state->mode_flags |= I915_MODE_FLAG_VRR;
210 }
211