1 // SPDX-License-Identifier: MIT 2 /* 3 * Copyright © 2023 Intel Corporation 4 */ 5 6 #include "i915_drv.h" 7 8 #include "intel_atomic.h" 9 #include "intel_display_types.h" 10 #include "intel_dp_mst.h" 11 #include "intel_fdi.h" 12 #include "intel_link_bw.h" 13 14 /** 15 * intel_link_bw_init_limits - initialize BW limits 16 * @i915: device instance 17 * @limits: link BW limits 18 * 19 * Initialize @limits. 20 */ 21 void intel_link_bw_init_limits(struct drm_i915_private *i915, struct intel_link_bw_limits *limits) 22 { 23 enum pipe pipe; 24 25 limits->force_fec_pipes = 0; 26 limits->bpp_limit_reached_pipes = 0; 27 for_each_pipe(i915, pipe) 28 limits->max_bpp_x16[pipe] = INT_MAX; 29 } 30 31 /** 32 * intel_link_bw_reduce_bpp - reduce maximum link bpp for a selected pipe 33 * @state: atomic state 34 * @limits: link BW limits 35 * @pipe_mask: mask of pipes to select from 36 * @reason: explanation of why bpp reduction is needed 37 * 38 * Select the pipe from @pipe_mask with the biggest link bpp value and set the 39 * maximum of link bpp in @limits below this value. Modeset the selected pipe, 40 * so that its state will get recomputed. 41 * 42 * This function can be called to resolve a link's BW overallocation by reducing 43 * the link bpp of one pipe on the link and hence reducing the total link BW. 44 * 45 * Returns 46 * - 0 in case of success 47 * - %-ENOSPC if no pipe can further reduce its link bpp 48 * - Other negative error, if modesetting the selected pipe failed 49 */ 50 int intel_link_bw_reduce_bpp(struct intel_atomic_state *state, 51 struct intel_link_bw_limits *limits, 52 u8 pipe_mask, 53 const char *reason) 54 { 55 struct drm_i915_private *i915 = to_i915(state->base.dev); 56 enum pipe max_bpp_pipe = INVALID_PIPE; 57 struct intel_crtc *crtc; 58 int max_bpp_x16 = 0; 59 60 for_each_intel_crtc_in_pipe_mask(&i915->drm, crtc, pipe_mask) { 61 struct intel_crtc_state *crtc_state; 62 int link_bpp_x16; 63 64 if (limits->bpp_limit_reached_pipes & BIT(crtc->pipe)) 65 continue; 66 67 crtc_state = intel_atomic_get_crtc_state(&state->base, 68 crtc); 69 if (IS_ERR(crtc_state)) 70 return PTR_ERR(crtc_state); 71 72 if (crtc_state->dsc.compression_enable) 73 link_bpp_x16 = crtc_state->dsc.compressed_bpp_x16; 74 else 75 /* 76 * TODO: for YUV420 the actual link bpp is only half 77 * of the pipe bpp value. The MST encoder's BW allocation 78 * is based on the pipe bpp value, set the actual link bpp 79 * limit here once the MST BW allocation is fixed. 80 */ 81 link_bpp_x16 = to_bpp_x16(crtc_state->pipe_bpp); 82 83 if (link_bpp_x16 > max_bpp_x16) { 84 max_bpp_x16 = link_bpp_x16; 85 max_bpp_pipe = crtc->pipe; 86 } 87 } 88 89 if (max_bpp_pipe == INVALID_PIPE) 90 return -ENOSPC; 91 92 limits->max_bpp_x16[max_bpp_pipe] = max_bpp_x16 - 1; 93 94 return intel_modeset_pipes_in_mask_early(state, reason, 95 BIT(max_bpp_pipe)); 96 } 97 98 /** 99 * intel_link_bw_set_bpp_limit_for_pipe - set link bpp limit for a pipe to its minimum 100 * @state: atomic state 101 * @old_limits: link BW limits 102 * @new_limits: link BW limits 103 * @pipe: pipe 104 * 105 * Set the link bpp limit for @pipe in @new_limits to its value in 106 * @old_limits and mark this limit as the minimum. This function must be 107 * called after a pipe's compute config function failed, @old_limits 108 * containing the bpp limit with which compute config previously passed. 109 * 110 * The function will fail if setting a minimum is not possible, either 111 * because the old and new limits match (and so would lead to a pipe compute 112 * config failure) or the limit is already at the minimum. 113 * 114 * Returns %true in case of success. 115 */ 116 bool 117 intel_link_bw_set_bpp_limit_for_pipe(struct intel_atomic_state *state, 118 const struct intel_link_bw_limits *old_limits, 119 struct intel_link_bw_limits *new_limits, 120 enum pipe pipe) 121 { 122 struct drm_i915_private *i915 = to_i915(state->base.dev); 123 124 if (pipe == INVALID_PIPE) 125 return false; 126 127 if (new_limits->max_bpp_x16[pipe] == 128 old_limits->max_bpp_x16[pipe]) 129 return false; 130 131 if (drm_WARN_ON(&i915->drm, 132 new_limits->bpp_limit_reached_pipes & BIT(pipe))) 133 return false; 134 135 new_limits->max_bpp_x16[pipe] = 136 old_limits->max_bpp_x16[pipe]; 137 new_limits->bpp_limit_reached_pipes |= BIT(pipe); 138 139 return true; 140 } 141 142 static int check_all_link_config(struct intel_atomic_state *state, 143 struct intel_link_bw_limits *limits) 144 { 145 /* TODO: Check additional shared display link configurations like MST */ 146 int ret; 147 148 ret = intel_dp_mst_atomic_check_link(state, limits); 149 if (ret) 150 return ret; 151 152 ret = intel_fdi_atomic_check_link(state, limits); 153 if (ret) 154 return ret; 155 156 return 0; 157 } 158 159 static bool 160 assert_link_limit_change_valid(struct drm_i915_private *i915, 161 const struct intel_link_bw_limits *old_limits, 162 const struct intel_link_bw_limits *new_limits) 163 { 164 bool bpps_changed = false; 165 enum pipe pipe; 166 167 /* FEC can't be forced off after it was forced on. */ 168 if (drm_WARN_ON(&i915->drm, 169 (old_limits->force_fec_pipes & new_limits->force_fec_pipes) != 170 old_limits->force_fec_pipes)) 171 return false; 172 173 for_each_pipe(i915, pipe) { 174 /* The bpp limit can only decrease. */ 175 if (drm_WARN_ON(&i915->drm, 176 new_limits->max_bpp_x16[pipe] > 177 old_limits->max_bpp_x16[pipe])) 178 return false; 179 180 if (new_limits->max_bpp_x16[pipe] < 181 old_limits->max_bpp_x16[pipe]) 182 bpps_changed = true; 183 } 184 185 /* At least one limit must change. */ 186 if (drm_WARN_ON(&i915->drm, 187 !bpps_changed && 188 new_limits->force_fec_pipes == 189 old_limits->force_fec_pipes)) 190 return false; 191 192 return true; 193 } 194 195 /** 196 * intel_link_bw_atomic_check - check display link states and set a fallback config if needed 197 * @state: atomic state 198 * @new_limits: link BW limits 199 * 200 * Check the configuration of all shared display links in @state and set new BW 201 * limits in @new_limits if there is a BW limitation. 202 * 203 * Returns: 204 * - 0 if the confugration is valid 205 * - %-EAGAIN, if the configuration is invalid and @new_limits got updated 206 * with fallback values with which the configuration of all CRTCs 207 * in @state must be recomputed 208 * - Other negative error, if the configuration is invalid without a 209 * fallback possibility, or the check failed for another reason 210 */ 211 int intel_link_bw_atomic_check(struct intel_atomic_state *state, 212 struct intel_link_bw_limits *new_limits) 213 { 214 struct drm_i915_private *i915 = to_i915(state->base.dev); 215 struct intel_link_bw_limits old_limits = *new_limits; 216 int ret; 217 218 ret = check_all_link_config(state, new_limits); 219 if (ret != -EAGAIN) 220 return ret; 221 222 if (!assert_link_limit_change_valid(i915, &old_limits, new_limits)) 223 return -EINVAL; 224 225 return -EAGAIN; 226 } 227