1 /* 2 * Copyright © 2015 Intel Corporation 3 * 4 * Permission is hereby granted, free of charge, to any person obtaining a 5 * copy of this software and associated documentation files (the "Software"), 6 * to deal in the Software without restriction, including without limitation 7 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 8 * and/or sell copies of the Software, and to permit persons to whom the 9 * Software is furnished to do so, subject to the following conditions: 10 * 11 * The above copyright notice and this permission notice (including the next 12 * paragraph) shall be included in all copies or substantial portions of the 13 * Software. 14 * 15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS 21 * IN THE SOFTWARE. 22 * 23 */ 24 25 /* 26 * Laptops with Intel GPUs which have panels that support controlling the 27 * backlight through DP AUX can actually use two different interfaces: Intel's 28 * proprietary DP AUX backlight interface, and the standard VESA backlight 29 * interface. Unfortunately, at the time of writing this a lot of laptops will 30 * advertise support for the standard VESA backlight interface when they 31 * don't properly support it. However, on these systems the Intel backlight 32 * interface generally does work properly. Additionally, these systems will 33 * usually just indicate that they use PWM backlight controls in their VBIOS 34 * for some reason. 35 */ 36 37 #include <linux/kconfig.h> 38 #include "i915_drv.h" 39 #include "intel_backlight.h" 40 #include "intel_display_types.h" 41 #include "intel_dp.h" 42 #include "intel_dp_aux_backlight.h" 43 44 /* TODO: 45 * Implement HDR, right now we just implement the bare minimum to bring us back into SDR mode so we 46 * can make people's backlights work in the mean time 47 */ 48 49 /* 50 * DP AUX registers for Intel's proprietary HDR backlight interface. We define 51 * them here since we'll likely be the only driver to ever use these. 52 */ 53 #define INTEL_EDP_HDR_TCON_CAP0 0x340 54 55 #define INTEL_EDP_HDR_TCON_CAP1 0x341 56 # define INTEL_EDP_HDR_TCON_2084_DECODE_CAP BIT(0) 57 # define INTEL_EDP_HDR_TCON_2020_GAMUT_CAP BIT(1) 58 # define INTEL_EDP_HDR_TCON_TONE_MAPPING_CAP BIT(2) 59 # define INTEL_EDP_HDR_TCON_SEGMENTED_BACKLIGHT_CAP BIT(3) 60 # define INTEL_EDP_HDR_TCON_BRIGHTNESS_NITS_CAP BIT(4) 61 # define INTEL_EDP_HDR_TCON_OPTIMIZATION_CAP BIT(5) 62 # define INTEL_EDP_HDR_TCON_SDP_COLORIMETRY_CAP BIT(6) 63 # define INTEL_EDP_HDR_TCON_SRGB_TO_PANEL_GAMUT_CONVERSION_CAP BIT(7) 64 65 #define INTEL_EDP_HDR_TCON_CAP2 0x342 66 # define INTEL_EDP_SDR_TCON_BRIGHTNESS_AUX_CAP BIT(0) 67 68 #define INTEL_EDP_HDR_TCON_CAP3 0x343 69 70 #define INTEL_EDP_HDR_GETSET_CTRL_PARAMS 0x344 71 # define INTEL_EDP_HDR_TCON_2084_DECODE_ENABLE BIT(0) 72 # define INTEL_EDP_HDR_TCON_2020_GAMUT_ENABLE BIT(1) 73 # define INTEL_EDP_HDR_TCON_TONE_MAPPING_ENABLE BIT(2) /* Pre-TGL+ */ 74 # define INTEL_EDP_HDR_TCON_SEGMENTED_BACKLIGHT_ENABLE BIT(3) 75 # define INTEL_EDP_HDR_TCON_BRIGHTNESS_AUX_ENABLE BIT(4) 76 # define INTEL_EDP_HDR_TCON_SRGB_TO_PANEL_GAMUT_ENABLE BIT(5) 77 /* Bit 6 is reserved */ 78 # define INTEL_EDP_HDR_TCON_SDP_COLORIMETRY_ENABLE BIT(7) 79 80 #define INTEL_EDP_HDR_CONTENT_LUMINANCE 0x346 /* Pre-TGL+ */ 81 #define INTEL_EDP_HDR_PANEL_LUMINANCE_OVERRIDE 0x34A 82 #define INTEL_EDP_SDR_LUMINANCE_LEVEL 0x352 83 #define INTEL_EDP_BRIGHTNESS_NITS_LSB 0x354 84 #define INTEL_EDP_BRIGHTNESS_NITS_MSB 0x355 85 #define INTEL_EDP_BRIGHTNESS_DELAY_FRAMES 0x356 86 #define INTEL_EDP_BRIGHTNESS_PER_FRAME_STEPS 0x357 87 88 #define INTEL_EDP_BRIGHTNESS_OPTIMIZATION_0 0x358 89 # define INTEL_EDP_TCON_USAGE_MASK GENMASK(0, 3) 90 # define INTEL_EDP_TCON_USAGE_UNKNOWN 0x0 91 # define INTEL_EDP_TCON_USAGE_DESKTOP 0x1 92 # define INTEL_EDP_TCON_USAGE_FULL_SCREEN_MEDIA 0x2 93 # define INTEL_EDP_TCON_USAGE_FULL_SCREEN_GAMING 0x3 94 # define INTEL_EDP_TCON_POWER_MASK BIT(4) 95 # define INTEL_EDP_TCON_POWER_DC (0 << 4) 96 # define INTEL_EDP_TCON_POWER_AC (1 << 4) 97 # define INTEL_EDP_TCON_OPTIMIZATION_STRENGTH_MASK GENMASK(5, 7) 98 99 #define INTEL_EDP_BRIGHTNESS_OPTIMIZATION_1 0x359 100 101 enum intel_dp_aux_backlight_modparam { 102 INTEL_DP_AUX_BACKLIGHT_AUTO = -1, 103 INTEL_DP_AUX_BACKLIGHT_OFF = 0, 104 INTEL_DP_AUX_BACKLIGHT_ON = 1, 105 INTEL_DP_AUX_BACKLIGHT_FORCE_VESA = 2, 106 INTEL_DP_AUX_BACKLIGHT_FORCE_INTEL = 3, 107 }; 108 109 static bool is_intel_tcon_cap(const u8 tcon_cap[4]) 110 { 111 return tcon_cap[0] >= 1; 112 } 113 114 /* Intel EDP backlight callbacks */ 115 static bool 116 intel_dp_aux_supports_hdr_backlight(struct intel_connector *connector) 117 { 118 struct drm_i915_private *i915 = to_i915(connector->base.dev); 119 struct intel_dp *intel_dp = enc_to_intel_dp(connector->encoder); 120 struct drm_dp_aux *aux = &intel_dp->aux; 121 struct intel_panel *panel = &connector->panel; 122 int ret; 123 u8 tcon_cap[4]; 124 125 intel_dp_wait_source_oui(intel_dp); 126 127 ret = drm_dp_dpcd_read(aux, INTEL_EDP_HDR_TCON_CAP0, tcon_cap, sizeof(tcon_cap)); 128 if (ret != sizeof(tcon_cap)) 129 return false; 130 131 if (!(tcon_cap[1] & INTEL_EDP_HDR_TCON_BRIGHTNESS_NITS_CAP)) 132 return false; 133 134 drm_dbg_kms(&i915->drm, "[CONNECTOR:%d:%s] Detected %s HDR backlight interface version %d\n", 135 connector->base.base.id, connector->base.name, 136 is_intel_tcon_cap(tcon_cap) ? "Intel" : "unsupported", tcon_cap[0]); 137 138 if (!is_intel_tcon_cap(tcon_cap)) 139 return false; 140 141 /* 142 * If we don't have HDR static metadata there is no way to 143 * runtime detect used range for nits based control. For now 144 * do not use Intel proprietary eDP backlight control if we 145 * don't have this data in panel EDID. In case we find panel 146 * which supports only nits based control, but doesn't provide 147 * HDR static metadata we need to start maintaining table of 148 * ranges for such panels. 149 */ 150 if (i915->params.enable_dpcd_backlight != INTEL_DP_AUX_BACKLIGHT_FORCE_INTEL && 151 !(connector->base.hdr_sink_metadata.hdmi_type1.metadata_type & 152 BIT(HDMI_STATIC_METADATA_TYPE1))) { 153 drm_info(&i915->drm, 154 "[CONNECTOR:%d:%s] Panel is missing HDR static metadata. Possible support for Intel HDR backlight interface is not used. If your backlight controls don't work try booting with i915.enable_dpcd_backlight=%d. needs this, please file a _new_ bug report on drm/i915, see " FDO_BUG_URL " for details.\n", 155 connector->base.base.id, connector->base.name, 156 INTEL_DP_AUX_BACKLIGHT_FORCE_INTEL); 157 return false; 158 } 159 160 panel->backlight.edp.intel.sdr_uses_aux = 161 tcon_cap[2] & INTEL_EDP_SDR_TCON_BRIGHTNESS_AUX_CAP; 162 163 return true; 164 } 165 166 static u32 167 intel_dp_aux_hdr_get_backlight(struct intel_connector *connector, enum pipe pipe) 168 { 169 struct drm_i915_private *i915 = to_i915(connector->base.dev); 170 struct intel_panel *panel = &connector->panel; 171 struct intel_dp *intel_dp = enc_to_intel_dp(connector->encoder); 172 u8 tmp; 173 u8 buf[2] = { 0 }; 174 175 if (drm_dp_dpcd_readb(&intel_dp->aux, INTEL_EDP_HDR_GETSET_CTRL_PARAMS, &tmp) != 1) { 176 drm_err(&i915->drm, "[CONNECTOR:%d:%s] Failed to read current backlight mode from DPCD\n", 177 connector->base.base.id, connector->base.name); 178 return 0; 179 } 180 181 if (!(tmp & INTEL_EDP_HDR_TCON_BRIGHTNESS_AUX_ENABLE)) { 182 if (!panel->backlight.edp.intel.sdr_uses_aux) { 183 u32 pwm_level = panel->backlight.pwm_funcs->get(connector, pipe); 184 185 return intel_backlight_level_from_pwm(connector, pwm_level); 186 } 187 188 /* Assume 100% brightness if backlight controls aren't enabled yet */ 189 return panel->backlight.max; 190 } 191 192 if (drm_dp_dpcd_read(&intel_dp->aux, INTEL_EDP_BRIGHTNESS_NITS_LSB, buf, 193 sizeof(buf)) != sizeof(buf)) { 194 drm_err(&i915->drm, "[CONNECTOR:%d:%s] Failed to read brightness from DPCD\n", 195 connector->base.base.id, connector->base.name); 196 return 0; 197 } 198 199 return (buf[1] << 8 | buf[0]); 200 } 201 202 static void 203 intel_dp_aux_hdr_set_aux_backlight(const struct drm_connector_state *conn_state, u32 level) 204 { 205 struct intel_connector *connector = to_intel_connector(conn_state->connector); 206 struct drm_device *dev = connector->base.dev; 207 struct intel_dp *intel_dp = enc_to_intel_dp(connector->encoder); 208 u8 buf[4] = { 0 }; 209 210 buf[0] = level & 0xFF; 211 buf[1] = (level & 0xFF00) >> 8; 212 213 if (drm_dp_dpcd_write(&intel_dp->aux, INTEL_EDP_BRIGHTNESS_NITS_LSB, buf, 214 sizeof(buf)) != sizeof(buf)) 215 drm_err(dev, "[CONNECTOR:%d:%s] Failed to write brightness level to DPCD\n", 216 connector->base.base.id, connector->base.name); 217 } 218 219 static void 220 intel_dp_aux_hdr_set_backlight(const struct drm_connector_state *conn_state, u32 level) 221 { 222 struct intel_connector *connector = to_intel_connector(conn_state->connector); 223 struct intel_panel *panel = &connector->panel; 224 225 if (panel->backlight.edp.intel.sdr_uses_aux) { 226 intel_dp_aux_hdr_set_aux_backlight(conn_state, level); 227 } else { 228 const u32 pwm_level = intel_backlight_level_to_pwm(connector, level); 229 230 intel_backlight_set_pwm_level(conn_state, pwm_level); 231 } 232 } 233 234 static void 235 intel_dp_aux_hdr_enable_backlight(const struct intel_crtc_state *crtc_state, 236 const struct drm_connector_state *conn_state, u32 level) 237 { 238 struct intel_connector *connector = to_intel_connector(conn_state->connector); 239 struct intel_panel *panel = &connector->panel; 240 struct drm_i915_private *i915 = to_i915(connector->base.dev); 241 struct intel_dp *intel_dp = enc_to_intel_dp(connector->encoder); 242 int ret; 243 u8 old_ctrl, ctrl; 244 245 intel_dp_wait_source_oui(intel_dp); 246 247 ret = drm_dp_dpcd_readb(&intel_dp->aux, INTEL_EDP_HDR_GETSET_CTRL_PARAMS, &old_ctrl); 248 if (ret != 1) { 249 drm_err(&i915->drm, "[CONNECTOR:%d:%s] Failed to read current backlight control mode: %d\n", 250 connector->base.base.id, connector->base.name, ret); 251 return; 252 } 253 254 ctrl = old_ctrl; 255 if (panel->backlight.edp.intel.sdr_uses_aux) { 256 ctrl |= INTEL_EDP_HDR_TCON_BRIGHTNESS_AUX_ENABLE; 257 intel_dp_aux_hdr_set_aux_backlight(conn_state, level); 258 } else { 259 u32 pwm_level = intel_backlight_level_to_pwm(connector, level); 260 261 panel->backlight.pwm_funcs->enable(crtc_state, conn_state, pwm_level); 262 263 ctrl &= ~INTEL_EDP_HDR_TCON_BRIGHTNESS_AUX_ENABLE; 264 } 265 266 if (ctrl != old_ctrl && 267 drm_dp_dpcd_writeb(&intel_dp->aux, INTEL_EDP_HDR_GETSET_CTRL_PARAMS, ctrl) != 1) 268 drm_err(&i915->drm, "[CONNECTOR:%d:%s] Failed to configure DPCD brightness controls\n", 269 connector->base.base.id, connector->base.name); 270 } 271 272 static void 273 intel_dp_aux_hdr_disable_backlight(const struct drm_connector_state *conn_state, u32 level) 274 { 275 struct intel_connector *connector = to_intel_connector(conn_state->connector); 276 struct intel_panel *panel = &connector->panel; 277 278 /* Nothing to do for AUX based backlight controls */ 279 if (panel->backlight.edp.intel.sdr_uses_aux) 280 return; 281 282 /* Note we want the actual pwm_level to be 0, regardless of pwm_min */ 283 panel->backlight.pwm_funcs->disable(conn_state, intel_backlight_invert_pwm_level(connector, 0)); 284 } 285 286 static const char *dpcd_vs_pwm_str(bool aux) 287 { 288 return aux ? "DPCD" : "PWM"; 289 } 290 291 static int 292 intel_dp_aux_hdr_setup_backlight(struct intel_connector *connector, enum pipe pipe) 293 { 294 struct drm_i915_private *i915 = to_i915(connector->base.dev); 295 struct intel_panel *panel = &connector->panel; 296 struct drm_luminance_range_info *luminance_range = 297 &connector->base.display_info.luminance_range; 298 int ret; 299 300 drm_dbg_kms(&i915->drm, "[CONNECTOR:%d:%s] SDR backlight is controlled through %s\n", 301 connector->base.base.id, connector->base.name, 302 dpcd_vs_pwm_str(panel->backlight.edp.intel.sdr_uses_aux)); 303 304 if (!panel->backlight.edp.intel.sdr_uses_aux) { 305 ret = panel->backlight.pwm_funcs->setup(connector, pipe); 306 if (ret < 0) { 307 drm_err(&i915->drm, 308 "[CONNECTOR:%d:%s] Failed to setup SDR backlight controls through PWM: %d\n", 309 connector->base.base.id, connector->base.name, ret); 310 return ret; 311 } 312 } 313 314 if (luminance_range->max_luminance) { 315 panel->backlight.max = luminance_range->max_luminance; 316 panel->backlight.min = luminance_range->min_luminance; 317 } else { 318 panel->backlight.max = 512; 319 panel->backlight.min = 0; 320 } 321 322 drm_dbg_kms(&i915->drm, "[CONNECTOR:%d:%s] Using AUX HDR interface for backlight control (range %d..%d)\n", 323 connector->base.base.id, connector->base.name, 324 panel->backlight.min, panel->backlight.max); 325 326 327 panel->backlight.level = intel_dp_aux_hdr_get_backlight(connector, pipe); 328 panel->backlight.enabled = panel->backlight.level != 0; 329 330 return 0; 331 } 332 333 /* VESA backlight callbacks */ 334 static u32 intel_dp_aux_vesa_get_backlight(struct intel_connector *connector, enum pipe unused) 335 { 336 return connector->panel.backlight.level; 337 } 338 339 static void 340 intel_dp_aux_vesa_set_backlight(const struct drm_connector_state *conn_state, u32 level) 341 { 342 struct intel_connector *connector = to_intel_connector(conn_state->connector); 343 struct intel_panel *panel = &connector->panel; 344 struct intel_dp *intel_dp = enc_to_intel_dp(connector->encoder); 345 346 if (!panel->backlight.edp.vesa.info.aux_set) { 347 const u32 pwm_level = intel_backlight_level_to_pwm(connector, level); 348 349 intel_backlight_set_pwm_level(conn_state, pwm_level); 350 } 351 352 drm_edp_backlight_set_level(&intel_dp->aux, &panel->backlight.edp.vesa.info, level); 353 } 354 355 static void 356 intel_dp_aux_vesa_enable_backlight(const struct intel_crtc_state *crtc_state, 357 const struct drm_connector_state *conn_state, u32 level) 358 { 359 struct intel_connector *connector = to_intel_connector(conn_state->connector); 360 struct intel_panel *panel = &connector->panel; 361 struct intel_dp *intel_dp = enc_to_intel_dp(connector->encoder); 362 363 if (!panel->backlight.edp.vesa.info.aux_enable) { 364 u32 pwm_level; 365 366 if (!panel->backlight.edp.vesa.info.aux_set) 367 pwm_level = intel_backlight_level_to_pwm(connector, level); 368 else 369 pwm_level = intel_backlight_invert_pwm_level(connector, 370 panel->backlight.pwm_level_max); 371 372 panel->backlight.pwm_funcs->enable(crtc_state, conn_state, pwm_level); 373 } 374 375 drm_edp_backlight_enable(&intel_dp->aux, &panel->backlight.edp.vesa.info, level); 376 } 377 378 static void intel_dp_aux_vesa_disable_backlight(const struct drm_connector_state *old_conn_state, 379 u32 level) 380 { 381 struct intel_connector *connector = to_intel_connector(old_conn_state->connector); 382 struct intel_panel *panel = &connector->panel; 383 struct intel_dp *intel_dp = enc_to_intel_dp(connector->encoder); 384 385 drm_edp_backlight_disable(&intel_dp->aux, &panel->backlight.edp.vesa.info); 386 387 if (!panel->backlight.edp.vesa.info.aux_enable) 388 panel->backlight.pwm_funcs->disable(old_conn_state, 389 intel_backlight_invert_pwm_level(connector, 0)); 390 } 391 392 static int intel_dp_aux_vesa_setup_backlight(struct intel_connector *connector, enum pipe pipe) 393 { 394 struct intel_dp *intel_dp = intel_attached_dp(connector); 395 struct intel_panel *panel = &connector->panel; 396 struct drm_i915_private *i915 = dp_to_i915(intel_dp); 397 u16 current_level; 398 u8 current_mode; 399 int ret; 400 401 ret = drm_edp_backlight_init(&intel_dp->aux, &panel->backlight.edp.vesa.info, 402 panel->vbt.backlight.pwm_freq_hz, intel_dp->edp_dpcd, 403 ¤t_level, ¤t_mode); 404 if (ret < 0) 405 return ret; 406 407 drm_dbg_kms(&i915->drm, "[CONNECTOR:%d:%s] AUX VESA backlight enable is controlled through %s\n", 408 connector->base.base.id, connector->base.name, 409 dpcd_vs_pwm_str(panel->backlight.edp.vesa.info.aux_enable)); 410 drm_dbg_kms(&i915->drm, "[CONNECTOR:%d:%s] AUX VESA backlight level is controlled through %s\n", 411 connector->base.base.id, connector->base.name, 412 dpcd_vs_pwm_str(panel->backlight.edp.vesa.info.aux_set)); 413 414 if (!panel->backlight.edp.vesa.info.aux_set || !panel->backlight.edp.vesa.info.aux_enable) { 415 ret = panel->backlight.pwm_funcs->setup(connector, pipe); 416 if (ret < 0) { 417 drm_err(&i915->drm, 418 "[CONNECTOR:%d:%s] Failed to setup PWM backlight controls for eDP backlight: %d\n", 419 connector->base.base.id, connector->base.name, ret); 420 return ret; 421 } 422 } 423 424 if (panel->backlight.edp.vesa.info.aux_set) { 425 panel->backlight.max = panel->backlight.edp.vesa.info.max; 426 panel->backlight.min = 0; 427 if (current_mode == DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD) { 428 panel->backlight.level = current_level; 429 panel->backlight.enabled = panel->backlight.level != 0; 430 } else { 431 panel->backlight.level = panel->backlight.max; 432 panel->backlight.enabled = false; 433 } 434 } else { 435 panel->backlight.max = panel->backlight.pwm_level_max; 436 panel->backlight.min = panel->backlight.pwm_level_min; 437 if (current_mode == DP_EDP_BACKLIGHT_CONTROL_MODE_PWM) { 438 panel->backlight.level = panel->backlight.pwm_funcs->get(connector, pipe); 439 panel->backlight.enabled = panel->backlight.pwm_enabled; 440 } else { 441 panel->backlight.level = panel->backlight.max; 442 panel->backlight.enabled = false; 443 } 444 } 445 446 drm_dbg_kms(&i915->drm, "[CONNECTOR:%d:%s] Using AUX VESA interface for backlight control\n", 447 connector->base.base.id, connector->base.name); 448 449 return 0; 450 } 451 452 static bool 453 intel_dp_aux_supports_vesa_backlight(struct intel_connector *connector) 454 { 455 struct intel_dp *intel_dp = intel_attached_dp(connector); 456 struct drm_i915_private *i915 = dp_to_i915(intel_dp); 457 458 if (drm_edp_backlight_supported(intel_dp->edp_dpcd)) { 459 drm_dbg_kms(&i915->drm, "[CONNECTOR:%d:%s] AUX Backlight Control Supported!\n", 460 connector->base.base.id, connector->base.name); 461 return true; 462 } 463 return false; 464 } 465 466 static const struct intel_panel_bl_funcs intel_dp_hdr_bl_funcs = { 467 .setup = intel_dp_aux_hdr_setup_backlight, 468 .enable = intel_dp_aux_hdr_enable_backlight, 469 .disable = intel_dp_aux_hdr_disable_backlight, 470 .set = intel_dp_aux_hdr_set_backlight, 471 .get = intel_dp_aux_hdr_get_backlight, 472 }; 473 474 static const struct intel_panel_bl_funcs intel_dp_vesa_bl_funcs = { 475 .setup = intel_dp_aux_vesa_setup_backlight, 476 .enable = intel_dp_aux_vesa_enable_backlight, 477 .disable = intel_dp_aux_vesa_disable_backlight, 478 .set = intel_dp_aux_vesa_set_backlight, 479 .get = intel_dp_aux_vesa_get_backlight, 480 }; 481 482 int intel_dp_aux_init_backlight_funcs(struct intel_connector *connector) 483 { 484 struct drm_device *dev = connector->base.dev; 485 struct intel_panel *panel = &connector->panel; 486 struct intel_dp *intel_dp = enc_to_intel_dp(connector->encoder); 487 struct drm_i915_private *i915 = dp_to_i915(intel_dp); 488 bool try_intel_interface = false, try_vesa_interface = false; 489 490 /* Check the VBT and user's module parameters to figure out which 491 * interfaces to probe 492 */ 493 switch (i915->params.enable_dpcd_backlight) { 494 case INTEL_DP_AUX_BACKLIGHT_OFF: 495 return -ENODEV; 496 case INTEL_DP_AUX_BACKLIGHT_AUTO: 497 switch (panel->vbt.backlight.type) { 498 case INTEL_BACKLIGHT_VESA_EDP_AUX_INTERFACE: 499 try_vesa_interface = true; 500 break; 501 case INTEL_BACKLIGHT_DISPLAY_DDI: 502 try_intel_interface = true; 503 break; 504 default: 505 return -ENODEV; 506 } 507 break; 508 case INTEL_DP_AUX_BACKLIGHT_ON: 509 if (panel->vbt.backlight.type != INTEL_BACKLIGHT_VESA_EDP_AUX_INTERFACE) 510 try_intel_interface = true; 511 512 try_vesa_interface = true; 513 break; 514 case INTEL_DP_AUX_BACKLIGHT_FORCE_VESA: 515 try_vesa_interface = true; 516 break; 517 case INTEL_DP_AUX_BACKLIGHT_FORCE_INTEL: 518 try_intel_interface = true; 519 break; 520 } 521 522 /* 523 * Since Intel has their own backlight control interface, the majority of machines out there 524 * using DPCD backlight controls with Intel GPUs will be using this interface as opposed to 525 * the VESA interface. However, other GPUs (such as Nvidia's) will always use the VESA 526 * interface. This means that there's quite a number of panels out there that will advertise 527 * support for both interfaces, primarily systems with Intel/Nvidia hybrid GPU setups. 528 * 529 * There's a catch to this though: on many panels that advertise support for both 530 * interfaces, the VESA backlight interface will stop working once we've programmed the 531 * panel with Intel's OUI - which is also required for us to be able to detect Intel's 532 * backlight interface at all. This means that the only sensible way for us to detect both 533 * interfaces is to probe for Intel's first, and VESA's second. 534 */ 535 if (try_intel_interface && intel_dp_aux_supports_hdr_backlight(connector)) { 536 drm_dbg_kms(dev, "[CONNECTOR:%d:%s] Using Intel proprietary eDP backlight controls\n", 537 connector->base.base.id, connector->base.name); 538 panel->backlight.funcs = &intel_dp_hdr_bl_funcs; 539 return 0; 540 } 541 542 if (try_vesa_interface && intel_dp_aux_supports_vesa_backlight(connector)) { 543 drm_dbg_kms(dev, "[CONNECTOR:%d:%s] Using VESA eDP backlight controls\n", 544 connector->base.base.id, connector->base.name); 545 panel->backlight.funcs = &intel_dp_vesa_bl_funcs; 546 return 0; 547 } 548 549 return -ENODEV; 550 } 551