xref: /linux/drivers/gpu/drm/i915/display/intel_vrr.c (revision 172cdcaefea5c297fdb3d20b7d5aff60ae4fbce6)
1 // SPDX-License-Identifier: MIT
2 /*
3  * Copyright © 2020 Intel Corporation
4  *
5  */
6 
7 #include "i915_drv.h"
8 #include "intel_display_types.h"
9 #include "intel_vrr.h"
10 
11 bool intel_vrr_is_capable(struct drm_connector *connector)
12 {
13 	struct intel_dp *intel_dp;
14 	const struct drm_display_info *info = &connector->display_info;
15 	struct drm_i915_private *i915 = to_i915(connector->dev);
16 
17 	if (connector->connector_type != DRM_MODE_CONNECTOR_eDP &&
18 	    connector->connector_type != DRM_MODE_CONNECTOR_DisplayPort)
19 		return false;
20 
21 	intel_dp = intel_attached_dp(to_intel_connector(connector));
22 	/*
23 	 * DP Sink is capable of VRR video timings if
24 	 * Ignore MSA bit is set in DPCD.
25 	 * EDID monitor range also should be atleast 10 for reasonable
26 	 * Adaptive Sync or Variable Refresh Rate end user experience.
27 	 */
28 	return HAS_VRR(i915) &&
29 		drm_dp_sink_can_do_video_without_timing_msa(intel_dp->dpcd) &&
30 		info->monitor_range.max_vfreq - info->monitor_range.min_vfreq > 10;
31 }
32 
33 void
34 intel_vrr_check_modeset(struct intel_atomic_state *state)
35 {
36 	int i;
37 	struct intel_crtc_state *old_crtc_state, *new_crtc_state;
38 	struct intel_crtc *crtc;
39 
40 	for_each_oldnew_intel_crtc_in_state(state, crtc, old_crtc_state,
41 					    new_crtc_state, i) {
42 		if (new_crtc_state->uapi.vrr_enabled !=
43 		    old_crtc_state->uapi.vrr_enabled)
44 			new_crtc_state->uapi.mode_changed = true;
45 	}
46 }
47 
48 /*
49  * Without VRR registers get latched at:
50  *  vblank_start
51  *
52  * With VRR the earliest registers can get latched is:
53  *  intel_vrr_vmin_vblank_start(), which if we want to maintain
54  *  the correct min vtotal is >=vblank_start+1
55  *
56  * The latest point registers can get latched is the vmax decision boundary:
57  *  intel_vrr_vmax_vblank_start()
58  *
59  * Between those two points the vblank exit starts (and hence registers get
60  * latched) ASAP after a push is sent.
61  *
62  * framestart_delay is programmable 0-3.
63  */
64 static int intel_vrr_vblank_exit_length(const struct intel_crtc_state *crtc_state)
65 {
66 	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
67 	struct drm_i915_private *i915 = to_i915(crtc->base.dev);
68 
69 	/* The hw imposes the extra scanline before frame start */
70 	return crtc_state->vrr.pipeline_full + i915->framestart_delay + 1;
71 }
72 
73 int intel_vrr_vmin_vblank_start(const struct intel_crtc_state *crtc_state)
74 {
75 	/* Min vblank actually determined by flipline that is always >=vmin+1 */
76 	return crtc_state->vrr.vmin + 1 - intel_vrr_vblank_exit_length(crtc_state);
77 }
78 
79 int intel_vrr_vmax_vblank_start(const struct intel_crtc_state *crtc_state)
80 {
81 	return crtc_state->vrr.vmax - intel_vrr_vblank_exit_length(crtc_state);
82 }
83 
84 void
85 intel_vrr_compute_config(struct intel_crtc_state *crtc_state,
86 			 struct drm_connector_state *conn_state)
87 {
88 	struct intel_connector *connector =
89 		to_intel_connector(conn_state->connector);
90 	struct drm_display_mode *adjusted_mode = &crtc_state->hw.adjusted_mode;
91 	const struct drm_display_info *info = &connector->base.display_info;
92 	int vmin, vmax;
93 
94 	if (!intel_vrr_is_capable(&connector->base))
95 		return;
96 
97 	if (adjusted_mode->flags & DRM_MODE_FLAG_INTERLACE)
98 		return;
99 
100 	if (!crtc_state->uapi.vrr_enabled)
101 		return;
102 
103 	vmin = DIV_ROUND_UP(adjusted_mode->crtc_clock * 1000,
104 			    adjusted_mode->crtc_htotal * info->monitor_range.max_vfreq);
105 	vmax = adjusted_mode->crtc_clock * 1000 /
106 		(adjusted_mode->crtc_htotal * info->monitor_range.min_vfreq);
107 
108 	vmin = max_t(int, vmin, adjusted_mode->crtc_vtotal);
109 	vmax = max_t(int, vmax, adjusted_mode->crtc_vtotal);
110 
111 	if (vmin >= vmax)
112 		return;
113 
114 	/*
115 	 * flipline determines the min vblank length the hardware will
116 	 * generate, and flipline>=vmin+1, hence we reduce vmin by one
117 	 * to make sure we can get the actual min vblank length.
118 	 */
119 	crtc_state->vrr.vmin = vmin - 1;
120 	crtc_state->vrr.vmax = vmax;
121 	crtc_state->vrr.enable = true;
122 
123 	crtc_state->vrr.flipline = crtc_state->vrr.vmin + 1;
124 
125 	/*
126 	 * FIXME: s/4/framestart_delay+1/ to get consistent
127 	 * earliest/latest points for register latching regardless
128 	 * of the framestart_delay used?
129 	 *
130 	 * FIXME: this really needs the extra scanline to provide consistent
131 	 * behaviour for all framestart_delay values. Otherwise with
132 	 * framestart_delay==3 we will end up extending the min vblank by
133 	 * one extra line.
134 	 */
135 	crtc_state->vrr.pipeline_full =
136 		min(255, crtc_state->vrr.vmin - adjusted_mode->crtc_vdisplay - 4 - 1);
137 
138 	crtc_state->mode_flags |= I915_MODE_FLAG_VRR;
139 }
140 
141 void intel_vrr_enable(struct intel_encoder *encoder,
142 		      const struct intel_crtc_state *crtc_state)
143 {
144 	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
145 	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
146 	u32 trans_vrr_ctl;
147 
148 	if (!crtc_state->vrr.enable)
149 		return;
150 
151 	trans_vrr_ctl = VRR_CTL_VRR_ENABLE |
152 		VRR_CTL_IGN_MAX_SHIFT | VRR_CTL_FLIP_LINE_EN |
153 		VRR_CTL_PIPELINE_FULL(crtc_state->vrr.pipeline_full) |
154 		VRR_CTL_PIPELINE_FULL_OVERRIDE;
155 
156 	intel_de_write(dev_priv, TRANS_VRR_VMIN(cpu_transcoder), crtc_state->vrr.vmin - 1);
157 	intel_de_write(dev_priv, TRANS_VRR_VMAX(cpu_transcoder), crtc_state->vrr.vmax - 1);
158 	intel_de_write(dev_priv, TRANS_VRR_CTL(cpu_transcoder), trans_vrr_ctl);
159 	intel_de_write(dev_priv, TRANS_VRR_FLIPLINE(cpu_transcoder), crtc_state->vrr.flipline - 1);
160 	intel_de_write(dev_priv, TRANS_PUSH(cpu_transcoder), TRANS_PUSH_EN);
161 }
162 
163 void intel_vrr_send_push(const struct intel_crtc_state *crtc_state)
164 {
165 	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
166 	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
167 	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
168 
169 	if (!crtc_state->vrr.enable)
170 		return;
171 
172 	intel_de_write(dev_priv, TRANS_PUSH(cpu_transcoder),
173 		       TRANS_PUSH_EN | TRANS_PUSH_SEND);
174 }
175 
176 void intel_vrr_disable(const struct intel_crtc_state *old_crtc_state)
177 {
178 	struct intel_crtc *crtc = to_intel_crtc(old_crtc_state->uapi.crtc);
179 	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
180 	enum transcoder cpu_transcoder = old_crtc_state->cpu_transcoder;
181 
182 	if (!old_crtc_state->vrr.enable)
183 		return;
184 
185 	intel_de_write(dev_priv, TRANS_VRR_CTL(cpu_transcoder), 0);
186 	intel_de_write(dev_priv, TRANS_PUSH(cpu_transcoder), 0);
187 }
188 
189 void intel_vrr_get_config(struct intel_crtc *crtc,
190 			  struct intel_crtc_state *crtc_state)
191 {
192 	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
193 	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
194 	u32 trans_vrr_ctl;
195 
196 	trans_vrr_ctl = intel_de_read(dev_priv, TRANS_VRR_CTL(cpu_transcoder));
197 	crtc_state->vrr.enable = trans_vrr_ctl & VRR_CTL_VRR_ENABLE;
198 	if (!crtc_state->vrr.enable)
199 		return;
200 
201 	if (trans_vrr_ctl & VRR_CTL_PIPELINE_FULL_OVERRIDE)
202 		crtc_state->vrr.pipeline_full = REG_FIELD_GET(VRR_CTL_PIPELINE_FULL_MASK, trans_vrr_ctl);
203 	if (trans_vrr_ctl & VRR_CTL_FLIP_LINE_EN)
204 		crtc_state->vrr.flipline = intel_de_read(dev_priv, TRANS_VRR_FLIPLINE(cpu_transcoder)) + 1;
205 	crtc_state->vrr.vmax = intel_de_read(dev_priv, TRANS_VRR_VMAX(cpu_transcoder)) + 1;
206 	crtc_state->vrr.vmin = intel_de_read(dev_priv, TRANS_VRR_VMIN(cpu_transcoder)) + 1;
207 
208 	crtc_state->mode_flags |= I915_MODE_FLAG_VRR;
209 }
210