drivers/gpu/drm/i915/intel_opregion.c

   1 /*
   2  * Copyright 2008 Intel Corporation <hong.liu@intel.com>
   3  * Copyright 2008 Red Hat <mjg@redhat.com>
   4  *
   5  * Permission is hereby granted, free of charge, to any person obtaining
   6  * a copy of this software and associated documentation files (the
   7  * "Software"), to deal in the Software without restriction, including
   8  * without limitation the rights to use, copy, modify, merge, publish,
   9  * distribute, sub license, and/or sell copies of the Software, and to
  10  * permit persons to whom the Software is furnished to do so, subject to
  11  * the following conditions:
  12  *
  13  * The above copyright notice and this permission notice (including the
  14  * next paragraph) shall be included in all copies or substantial
  15  * portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  18  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  19  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  20  * NON-INFRINGEMENT.  IN NO EVENT SHALL INTEL AND/OR ITS SUPPLIERS BE
  21  * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  22  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  23  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  24  * SOFTWARE.
  25  *
  26  */
  27
  28 #include <linux/acpi.h>
  29 #include <linux/dmi.h>
  30 #include <acpi/video.h>
  31
  32 #include <drm/drmP.h>
  33 #include <drm/i915_drm.h>
  34 #include "i915_drv.h"
  35 #include "intel_drv.h"
  36
  37 #define OPREGION_HEADER_OFFSET 0
  38 #define OPREGION_ACPI_OFFSET   0x100
  39 #define   ACPI_CLID 0x01ac /* current lid state indicator */
  40 #define   ACPI_CDCK 0x01b0 /* current docking state indicator */
  41 #define OPREGION_SWSCI_OFFSET  0x200
  42 #define OPREGION_ASLE_OFFSET   0x300
  43 #define OPREGION_VBT_OFFSET    0x400
  44 #define OPREGION_ASLE_EXT_OFFSET        0x1C00
  45
  46 #define OPREGION_SIGNATURE "IntelGraphicsMem"
  47 #define MBOX_ACPI      (1<<0)
  48 #define MBOX_SWSCI     (1<<1)
  49 #define MBOX_ASLE      (1<<2)
  50 #define MBOX_ASLE_EXT  (1<<4)
  51
  52 struct opregion_header {
  53         u8 signature[16];
  54         u32 size;
  55         u32 opregion_ver;
  56         u8 bios_ver[32];
  57         u8 vbios_ver[16];
  58         u8 driver_ver[16];
  59         u32 mboxes;
  60         u32 driver_model;
  61         u32 pcon;
  62         u8 dver[32];
  63         u8 rsvd[124];
  64 } __packed;
  65
  66 /* OpRegion mailbox #1: public ACPI methods */
  67 struct opregion_acpi {
  68         u32 drdy;       /* driver readiness */
  69         u32 csts;       /* notification status */
  70         u32 cevt;       /* current event */
  71         u8 rsvd1[20];
  72         u32 didl[8];    /* supported display devices ID list */
  73         u32 cpdl[8];    /* currently presented display list */
  74         u32 cadl[8];    /* currently active display list */
  75         u32 nadl[8];    /* next active devices list */
  76         u32 aslp;       /* ASL sleep time-out */
  77         u32 tidx;       /* toggle table index */
  78         u32 chpd;       /* current hotplug enable indicator */
  79         u32 clid;       /* current lid state*/
  80         u32 cdck;       /* current docking state */
  81         u32 sxsw;       /* Sx state resume */
  82         u32 evts;       /* ASL supported events */
  83         u32 cnot;       /* current OS notification */
  84         u32 nrdy;       /* driver status */
  85         u32 did2[7];    /* extended supported display devices ID list */
  86         u32 cpd2[7];    /* extended attached display devices list */
  87         u8 rsvd2[4];
  88 } __packed;
  89
  90 /* OpRegion mailbox #2: SWSCI */
  91 struct opregion_swsci {
  92         u32 scic;       /* SWSCI command|status|data */
  93         u32 parm;       /* command parameters */
  94         u32 dslp;       /* driver sleep time-out */
  95         u8 rsvd[244];
  96 } __packed;
  97
  98 /* OpRegion mailbox #3: ASLE */
  99 struct opregion_asle {
 100         u32 ardy;       /* driver readiness */
 101         u32 aslc;       /* ASLE interrupt command */
 102         u32 tche;       /* technology enabled indicator */
 103         u32 alsi;       /* current ALS illuminance reading */
 104         u32 bclp;       /* backlight brightness to set */
 105         u32 pfit;       /* panel fitting state */
 106         u32 cblv;       /* current brightness level */
 107         u16 bclm[20];   /* backlight level duty cycle mapping table */
 108         u32 cpfm;       /* current panel fitting mode */
 109         u32 epfm;       /* enabled panel fitting modes */
 110         u8 plut[74];    /* panel LUT and identifier */
 111         u32 pfmb;       /* PWM freq and min brightness */
 112         u32 cddv;       /* color correction default values */
 113         u32 pcft;       /* power conservation features */
 114         u32 srot;       /* supported rotation angles */
 115         u32 iuer;       /* IUER events */
 116         u64 fdss;
 117         u32 fdsp;
 118         u32 stat;
 119         u64 rvda;       /* Physical address of raw vbt data */
 120         u32 rvds;       /* Size of raw vbt data */
 121         u8 rsvd[58];
 122 } __packed;
 123
 124 /* OpRegion mailbox #5: ASLE ext */
 125 struct opregion_asle_ext {
 126         u32 phed;       /* Panel Header */
 127         u8 bddc[256];   /* Panel EDID */
 128         u8 rsvd[764];
 129 } __packed;
 130
 131 /* Driver readiness indicator */
 132 #define ASLE_ARDY_READY         (1 << 0)
 133 #define ASLE_ARDY_NOT_READY     (0 << 0)
 134
 135 /* ASLE Interrupt Command (ASLC) bits */
 136 #define ASLC_SET_ALS_ILLUM              (1 << 0)
 137 #define ASLC_SET_BACKLIGHT              (1 << 1)
 138 #define ASLC_SET_PFIT                   (1 << 2)
 139 #define ASLC_SET_PWM_FREQ               (1 << 3)
 140 #define ASLC_SUPPORTED_ROTATION_ANGLES  (1 << 4)
 141 #define ASLC_BUTTON_ARRAY               (1 << 5)
 142 #define ASLC_CONVERTIBLE_INDICATOR      (1 << 6)
 143 #define ASLC_DOCKING_INDICATOR          (1 << 7)
 144 #define ASLC_ISCT_STATE_CHANGE          (1 << 8)
 145 #define ASLC_REQ_MSK                    0x1ff
 146 /* response bits */
 147 #define ASLC_ALS_ILLUM_FAILED           (1 << 10)
 148 #define ASLC_BACKLIGHT_FAILED           (1 << 12)
 149 #define ASLC_PFIT_FAILED                (1 << 14)
 150 #define ASLC_PWM_FREQ_FAILED            (1 << 16)
 151 #define ASLC_ROTATION_ANGLES_FAILED     (1 << 18)
 152 #define ASLC_BUTTON_ARRAY_FAILED        (1 << 20)
 153 #define ASLC_CONVERTIBLE_FAILED         (1 << 22)
 154 #define ASLC_DOCKING_FAILED             (1 << 24)
 155 #define ASLC_ISCT_STATE_FAILED          (1 << 26)
 156
 157 /* Technology enabled indicator */
 158 #define ASLE_TCHE_ALS_EN        (1 << 0)
 159 #define ASLE_TCHE_BLC_EN        (1 << 1)
 160 #define ASLE_TCHE_PFIT_EN       (1 << 2)
 161 #define ASLE_TCHE_PFMB_EN       (1 << 3)
 162
 163 /* ASLE backlight brightness to set */
 164 #define ASLE_BCLP_VALID                (1<<31)
 165 #define ASLE_BCLP_MSK          (~(1<<31))
 166
 167 /* ASLE panel fitting request */
 168 #define ASLE_PFIT_VALID         (1<<31)
 169 #define ASLE_PFIT_CENTER (1<<0)
 170 #define ASLE_PFIT_STRETCH_TEXT (1<<1)
 171 #define ASLE_PFIT_STRETCH_GFX (1<<2)
 172
 173 /* PWM frequency and minimum brightness */
 174 #define ASLE_PFMB_BRIGHTNESS_MASK (0xff)
 175 #define ASLE_PFMB_BRIGHTNESS_VALID (1<<8)
 176 #define ASLE_PFMB_PWM_MASK (0x7ffffe00)
 177 #define ASLE_PFMB_PWM_VALID (1<<31)
 178
 179 #define ASLE_CBLV_VALID         (1<<31)
 180
 181 /* IUER */
 182 #define ASLE_IUER_DOCKING               (1 << 7)
 183 #define ASLE_IUER_CONVERTIBLE           (1 << 6)
 184 #define ASLE_IUER_ROTATION_LOCK_BTN     (1 << 4)
 185 #define ASLE_IUER_VOLUME_DOWN_BTN       (1 << 3)
 186 #define ASLE_IUER_VOLUME_UP_BTN         (1 << 2)
 187 #define ASLE_IUER_WINDOWS_BTN           (1 << 1)
 188 #define ASLE_IUER_POWER_BTN             (1 << 0)
 189
 190 /* Software System Control Interrupt (SWSCI) */
 191 #define SWSCI_SCIC_INDICATOR            (1 << 0)
 192 #define SWSCI_SCIC_MAIN_FUNCTION_SHIFT  1
 193 #define SWSCI_SCIC_MAIN_FUNCTION_MASK   (0xf << 1)
 194 #define SWSCI_SCIC_SUB_FUNCTION_SHIFT   8
 195 #define SWSCI_SCIC_SUB_FUNCTION_MASK    (0xff << 8)
 196 #define SWSCI_SCIC_EXIT_PARAMETER_SHIFT 8
 197 #define SWSCI_SCIC_EXIT_PARAMETER_MASK  (0xff << 8)
 198 #define SWSCI_SCIC_EXIT_STATUS_SHIFT    5
 199 #define SWSCI_SCIC_EXIT_STATUS_MASK     (7 << 5)
 200 #define SWSCI_SCIC_EXIT_STATUS_SUCCESS  1
 201
 202 #define SWSCI_FUNCTION_CODE(main, sub) \
 203         ((main) << SWSCI_SCIC_MAIN_FUNCTION_SHIFT | \
 204          (sub) << SWSCI_SCIC_SUB_FUNCTION_SHIFT)
 205
 206 /* SWSCI: Get BIOS Data (GBDA) */
 207 #define SWSCI_GBDA                      4
 208 #define SWSCI_GBDA_SUPPORTED_CALLS      SWSCI_FUNCTION_CODE(SWSCI_GBDA, 0)
 209 #define SWSCI_GBDA_REQUESTED_CALLBACKS  SWSCI_FUNCTION_CODE(SWSCI_GBDA, 1)
 210 #define SWSCI_GBDA_BOOT_DISPLAY_PREF    SWSCI_FUNCTION_CODE(SWSCI_GBDA, 4)
 211 #define SWSCI_GBDA_PANEL_DETAILS        SWSCI_FUNCTION_CODE(SWSCI_GBDA, 5)
 212 #define SWSCI_GBDA_TV_STANDARD          SWSCI_FUNCTION_CODE(SWSCI_GBDA, 6)
 213 #define SWSCI_GBDA_INTERNAL_GRAPHICS    SWSCI_FUNCTION_CODE(SWSCI_GBDA, 7)
 214 #define SWSCI_GBDA_SPREAD_SPECTRUM      SWSCI_FUNCTION_CODE(SWSCI_GBDA, 10)
 215
 216 /* SWSCI: System BIOS Callbacks (SBCB) */
 217 #define SWSCI_SBCB                      6
 218 #define SWSCI_SBCB_SUPPORTED_CALLBACKS  SWSCI_FUNCTION_CODE(SWSCI_SBCB, 0)
 219 #define SWSCI_SBCB_INIT_COMPLETION      SWSCI_FUNCTION_CODE(SWSCI_SBCB, 1)
 220 #define SWSCI_SBCB_PRE_HIRES_SET_MODE   SWSCI_FUNCTION_CODE(SWSCI_SBCB, 3)
 221 #define SWSCI_SBCB_POST_HIRES_SET_MODE  SWSCI_FUNCTION_CODE(SWSCI_SBCB, 4)
 222 #define SWSCI_SBCB_DISPLAY_SWITCH       SWSCI_FUNCTION_CODE(SWSCI_SBCB, 5)
 223 #define SWSCI_SBCB_SET_TV_FORMAT        SWSCI_FUNCTION_CODE(SWSCI_SBCB, 6)
 224 #define SWSCI_SBCB_ADAPTER_POWER_STATE  SWSCI_FUNCTION_CODE(SWSCI_SBCB, 7)
 225 #define SWSCI_SBCB_DISPLAY_POWER_STATE  SWSCI_FUNCTION_CODE(SWSCI_SBCB, 8)
 226 #define SWSCI_SBCB_SET_BOOT_DISPLAY     SWSCI_FUNCTION_CODE(SWSCI_SBCB, 9)
 227 #define SWSCI_SBCB_SET_PANEL_DETAILS    SWSCI_FUNCTION_CODE(SWSCI_SBCB, 10)
 228 #define SWSCI_SBCB_SET_INTERNAL_GFX     SWSCI_FUNCTION_CODE(SWSCI_SBCB, 11)
 229 #define SWSCI_SBCB_POST_HIRES_TO_DOS_FS SWSCI_FUNCTION_CODE(SWSCI_SBCB, 16)
 230 #define SWSCI_SBCB_SUSPEND_RESUME       SWSCI_FUNCTION_CODE(SWSCI_SBCB, 17)
 231 #define SWSCI_SBCB_SET_SPREAD_SPECTRUM  SWSCI_FUNCTION_CODE(SWSCI_SBCB, 18)
 232 #define SWSCI_SBCB_POST_VBE_PM          SWSCI_FUNCTION_CODE(SWSCI_SBCB, 19)
 233 #define SWSCI_SBCB_ENABLE_DISABLE_AUDIO SWSCI_FUNCTION_CODE(SWSCI_SBCB, 21)
 234
 235 /*
 236  * ACPI Specification, Revision 5.0, Appendix B.3.2 _DOD (Enumerate All Devices
 237  * Attached to the Display Adapter).
 238  */
 239 #define ACPI_DISPLAY_INDEX_SHIFT                0
 240 #define ACPI_DISPLAY_INDEX_MASK                 (0xf << 0)
 241 #define ACPI_DISPLAY_PORT_ATTACHMENT_SHIFT      4
 242 #define ACPI_DISPLAY_PORT_ATTACHMENT_MASK       (0xf << 4)
 243 #define ACPI_DISPLAY_TYPE_SHIFT                 8
 244 #define ACPI_DISPLAY_TYPE_MASK                  (0xf << 8)
 245 #define ACPI_DISPLAY_TYPE_OTHER                 (0 << 8)
 246 #define ACPI_DISPLAY_TYPE_VGA                   (1 << 8)
 247 #define ACPI_DISPLAY_TYPE_TV                    (2 << 8)
 248 #define ACPI_DISPLAY_TYPE_EXTERNAL_DIGITAL      (3 << 8)
 249 #define ACPI_DISPLAY_TYPE_INTERNAL_DIGITAL      (4 << 8)
 250 #define ACPI_VENDOR_SPECIFIC_SHIFT              12
 251 #define ACPI_VENDOR_SPECIFIC_MASK               (0xf << 12)
 252 #define ACPI_BIOS_CAN_DETECT                    (1 << 16)
 253 #define ACPI_DEPENDS_ON_VGA                     (1 << 17)
 254 #define ACPI_PIPE_ID_SHIFT                      18
 255 #define ACPI_PIPE_ID_MASK                       (7 << 18)
 256 #define ACPI_DEVICE_ID_SCHEME                   (1 << 31)
 257
 258 #define MAX_DSLP        1500
 259
 260 static int swsci(struct drm_i915_private *dev_priv,
 261                  u32 function, u32 parm, u32 *parm_out)
 262 {
 263         struct opregion_swsci *swsci = dev_priv->opregion.swsci;
 264         struct pci_dev *pdev = dev_priv->drm.pdev;
 265         u32 main_function, sub_function, scic;
 266         u16 swsci_val;
 267         u32 dslp;
 268
 269         if (!swsci)
 270                 return -ENODEV;
 271
 272         main_function = (function & SWSCI_SCIC_MAIN_FUNCTION_MASK) >>
 273                 SWSCI_SCIC_MAIN_FUNCTION_SHIFT;
 274         sub_function = (function & SWSCI_SCIC_SUB_FUNCTION_MASK) >>
 275                 SWSCI_SCIC_SUB_FUNCTION_SHIFT;
 276
 277         /* Check if we can call the function. See swsci_setup for details. */
 278         if (main_function == SWSCI_SBCB) {
 279                 if ((dev_priv->opregion.swsci_sbcb_sub_functions &
 280                      (1 << sub_function)) == 0)
 281                         return -EINVAL;
 282         } else if (main_function == SWSCI_GBDA) {
 283                 if ((dev_priv->opregion.swsci_gbda_sub_functions &
 284                      (1 << sub_function)) == 0)
 285                         return -EINVAL;
 286         }
 287
 288         /* Driver sleep timeout in ms. */
 289         dslp = swsci->dslp;
 290         if (!dslp) {
 291                 /* The spec says 2ms should be the default, but it's too small
 292                  * for some machines. */
 293                 dslp = 50;
 294         } else if (dslp > MAX_DSLP) {
 295                 /* Hey bios, trust must be earned. */
 296                 DRM_INFO_ONCE("ACPI BIOS requests an excessive sleep of %u ms, "
 297                               "using %u ms instead\n", dslp, MAX_DSLP);
 298                 dslp = MAX_DSLP;
 299         }
 300
 301         /* The spec tells us to do this, but we are the only user... */
 302         scic = swsci->scic;
 303         if (scic & SWSCI_SCIC_INDICATOR) {
 304                 DRM_DEBUG_DRIVER("SWSCI request already in progress\n");
 305                 return -EBUSY;
 306         }
 307
 308         scic = function | SWSCI_SCIC_INDICATOR;
 309
 310         swsci->parm = parm;
 311         swsci->scic = scic;
 312
 313         /* Ensure SCI event is selected and event trigger is cleared. */
 314         pci_read_config_word(pdev, SWSCI, &swsci_val);
 315         if (!(swsci_val & SWSCI_SCISEL) || (swsci_val & SWSCI_GSSCIE)) {
 316                 swsci_val |= SWSCI_SCISEL;
 317                 swsci_val &= ~SWSCI_GSSCIE;
 318                 pci_write_config_word(pdev, SWSCI, swsci_val);
 319         }
 320
 321         /* Use event trigger to tell bios to check the mail. */
 322         swsci_val |= SWSCI_GSSCIE;
 323         pci_write_config_word(pdev, SWSCI, swsci_val);
 324
 325         /* Poll for the result. */
 326 #define C (((scic = swsci->scic) & SWSCI_SCIC_INDICATOR) == 0)
 327         if (wait_for(C, dslp)) {
 328                 DRM_DEBUG_DRIVER("SWSCI request timed out\n");
 329                 return -ETIMEDOUT;
 330         }
 331
 332         scic = (scic & SWSCI_SCIC_EXIT_STATUS_MASK) >>
 333                 SWSCI_SCIC_EXIT_STATUS_SHIFT;
 334
 335         /* Note: scic == 0 is an error! */
 336         if (scic != SWSCI_SCIC_EXIT_STATUS_SUCCESS) {
 337                 DRM_DEBUG_DRIVER("SWSCI request error %u\n", scic);
 338                 return -EIO;
 339         }
 340
 341         if (parm_out)
 342                 *parm_out = swsci->parm;
 343
 344         return 0;
 345
 346 #undef C
 347 }
 348
 349 #define DISPLAY_TYPE_CRT                        0
 350 #define DISPLAY_TYPE_TV                         1
 351 #define DISPLAY_TYPE_EXTERNAL_FLAT_PANEL        2
 352 #define DISPLAY_TYPE_INTERNAL_FLAT_PANEL        3
 353
 354 int intel_opregion_notify_encoder(struct intel_encoder *intel_encoder,
 355                                   bool enable)
 356 {
 357         struct drm_i915_private *dev_priv = to_i915(intel_encoder->base.dev);
 358         u32 parm = 0;
 359         u32 type = 0;
 360         u32 port;
 361
 362         /* don't care about old stuff for now */
 363         if (!HAS_DDI(dev_priv))
 364                 return 0;
 365
 366         if (intel_encoder->type == INTEL_OUTPUT_DSI)
 367                 port = 0;
 368         else
 369                 port = intel_ddi_get_encoder_port(intel_encoder);
 370
 371         if (port == PORT_E)  {
 372                 port = 0;
 373         } else {
 374                 parm |= 1 << port;
 375                 port++;
 376         }
 377
 378         if (!enable)
 379                 parm |= 4 << 8;
 380
 381         switch (intel_encoder->type) {
 382         case INTEL_OUTPUT_ANALOG:
 383                 type = DISPLAY_TYPE_CRT;
 384                 break;
 385         case INTEL_OUTPUT_UNKNOWN:
 386         case INTEL_OUTPUT_DP:
 387         case INTEL_OUTPUT_HDMI:
 388         case INTEL_OUTPUT_DP_MST:
 389                 type = DISPLAY_TYPE_EXTERNAL_FLAT_PANEL;
 390                 break;
 391         case INTEL_OUTPUT_EDP:
 392         case INTEL_OUTPUT_DSI:
 393                 type = DISPLAY_TYPE_INTERNAL_FLAT_PANEL;
 394                 break;
 395         default:
 396                 WARN_ONCE(1, "unsupported intel_encoder type %d\n",
 397                           intel_encoder->type);
 398                 return -EINVAL;
 399         }
 400
 401         parm |= type << (16 + port * 3);
 402
 403         return swsci(dev_priv, SWSCI_SBCB_DISPLAY_POWER_STATE, parm, NULL);
 404 }
 405
 406 static const struct {
 407         pci_power_t pci_power_state;
 408         u32 parm;
 409 } power_state_map[] = {
 410         { PCI_D0,       0x00 },
 411         { PCI_D1,       0x01 },
 412         { PCI_D2,       0x02 },
 413         { PCI_D3hot,    0x04 },
 414         { PCI_D3cold,   0x04 },
 415 };
 416
 417 int intel_opregion_notify_adapter(struct drm_i915_private *dev_priv,
 418                                   pci_power_t state)
 419 {
 420         int i;
 421
 422         if (!HAS_DDI(dev_priv))
 423                 return 0;
 424
 425         for (i = 0; i < ARRAY_SIZE(power_state_map); i++) {
 426                 if (state == power_state_map[i].pci_power_state)
 427                         return swsci(dev_priv, SWSCI_SBCB_ADAPTER_POWER_STATE,
 428                                      power_state_map[i].parm, NULL);
 429         }
 430
 431         return -EINVAL;
 432 }
 433
 434 static u32 asle_set_backlight(struct drm_i915_private *dev_priv, u32 bclp)
 435 {
 436         struct intel_connector *connector;
 437         struct opregion_asle *asle = dev_priv->opregion.asle;
 438         struct drm_device *dev = &dev_priv->drm;
 439
 440         DRM_DEBUG_DRIVER("bclp = 0x%08x\n", bclp);
 441
 442         if (acpi_video_get_backlight_type() == acpi_backlight_native) {
 443                 DRM_DEBUG_KMS("opregion backlight request ignored\n");
 444                 return 0;
 445         }
 446
 447         if (!(bclp & ASLE_BCLP_VALID))
 448                 return ASLC_BACKLIGHT_FAILED;
 449
 450         bclp &= ASLE_BCLP_MSK;
 451         if (bclp > 255)
 452                 return ASLC_BACKLIGHT_FAILED;
 453
 454         drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
 455
 456         /*
 457          * Update backlight on all connectors that support backlight (usually
 458          * only one).
 459          */
 460         DRM_DEBUG_KMS("updating opregion backlight %d/255\n", bclp);
 461         for_each_intel_connector(dev, connector)
 462                 intel_panel_set_backlight_acpi(connector, bclp, 255);
 463         asle->cblv = DIV_ROUND_UP(bclp * 100, 255) | ASLE_CBLV_VALID;
 464
 465         drm_modeset_unlock(&dev->mode_config.connection_mutex);
 466
 467
 468         return 0;
 469 }
 470
 471 static u32 asle_set_als_illum(struct drm_i915_private *dev_priv, u32 alsi)
 472 {
 473         /* alsi is the current ALS reading in lux. 0 indicates below sensor
 474            range, 0xffff indicates above sensor range. 1-0xfffe are valid */
 475         DRM_DEBUG_DRIVER("Illum is not supported\n");
 476         return ASLC_ALS_ILLUM_FAILED;
 477 }
 478
 479 static u32 asle_set_pwm_freq(struct drm_i915_private *dev_priv, u32 pfmb)
 480 {
 481         DRM_DEBUG_DRIVER("PWM freq is not supported\n");
 482         return ASLC_PWM_FREQ_FAILED;
 483 }
 484
 485 static u32 asle_set_pfit(struct drm_i915_private *dev_priv, u32 pfit)
 486 {
 487         /* Panel fitting is currently controlled by the X code, so this is a
 488            noop until modesetting support works fully */
 489         DRM_DEBUG_DRIVER("Pfit is not supported\n");
 490         return ASLC_PFIT_FAILED;
 491 }
 492
 493 static u32 asle_set_supported_rotation_angles(struct drm_i915_private *dev_priv, u32 srot)
 494 {
 495         DRM_DEBUG_DRIVER("SROT is not supported\n");
 496         return ASLC_ROTATION_ANGLES_FAILED;
 497 }
 498
 499 static u32 asle_set_button_array(struct drm_i915_private *dev_priv, u32 iuer)
 500 {
 501         if (!iuer)
 502                 DRM_DEBUG_DRIVER("Button array event is not supported (nothing)\n");
 503         if (iuer & ASLE_IUER_ROTATION_LOCK_BTN)
 504                 DRM_DEBUG_DRIVER("Button array event is not supported (rotation lock)\n");
 505         if (iuer & ASLE_IUER_VOLUME_DOWN_BTN)
 506                 DRM_DEBUG_DRIVER("Button array event is not supported (volume down)\n");
 507         if (iuer & ASLE_IUER_VOLUME_UP_BTN)
 508                 DRM_DEBUG_DRIVER("Button array event is not supported (volume up)\n");
 509         if (iuer & ASLE_IUER_WINDOWS_BTN)
 510                 DRM_DEBUG_DRIVER("Button array event is not supported (windows)\n");
 511         if (iuer & ASLE_IUER_POWER_BTN)
 512                 DRM_DEBUG_DRIVER("Button array event is not supported (power)\n");
 513
 514         return ASLC_BUTTON_ARRAY_FAILED;
 515 }
 516
 517 static u32 asle_set_convertible(struct drm_i915_private *dev_priv, u32 iuer)
 518 {
 519         if (iuer & ASLE_IUER_CONVERTIBLE)
 520                 DRM_DEBUG_DRIVER("Convertible is not supported (clamshell)\n");
 521         else
 522                 DRM_DEBUG_DRIVER("Convertible is not supported (slate)\n");
 523
 524         return ASLC_CONVERTIBLE_FAILED;
 525 }
 526
 527 static u32 asle_set_docking(struct drm_i915_private *dev_priv, u32 iuer)
 528 {
 529         if (iuer & ASLE_IUER_DOCKING)
 530                 DRM_DEBUG_DRIVER("Docking is not supported (docked)\n");
 531         else
 532                 DRM_DEBUG_DRIVER("Docking is not supported (undocked)\n");
 533
 534         return ASLC_DOCKING_FAILED;
 535 }
 536
 537 static u32 asle_isct_state(struct drm_i915_private *dev_priv)
 538 {
 539         DRM_DEBUG_DRIVER("ISCT is not supported\n");
 540         return ASLC_ISCT_STATE_FAILED;
 541 }
 542
 543 static void asle_work(struct work_struct *work)
 544 {
 545         struct intel_opregion *opregion =
 546                 container_of(work, struct intel_opregion, asle_work);
 547         struct drm_i915_private *dev_priv =
 548                 container_of(opregion, struct drm_i915_private, opregion);
 549         struct opregion_asle *asle = dev_priv->opregion.asle;
 550         u32 aslc_stat = 0;
 551         u32 aslc_req;
 552
 553         if (!asle)
 554                 return;
 555
 556         aslc_req = asle->aslc;
 557
 558         if (!(aslc_req & ASLC_REQ_MSK)) {
 559                 DRM_DEBUG_DRIVER("No request on ASLC interrupt 0x%08x\n",
 560                                  aslc_req);
 561                 return;
 562         }
 563
 564         if (aslc_req & ASLC_SET_ALS_ILLUM)
 565                 aslc_stat |= asle_set_als_illum(dev_priv, asle->alsi);
 566
 567         if (aslc_req & ASLC_SET_BACKLIGHT)
 568                 aslc_stat |= asle_set_backlight(dev_priv, asle->bclp);
 569
 570         if (aslc_req & ASLC_SET_PFIT)
 571                 aslc_stat |= asle_set_pfit(dev_priv, asle->pfit);
 572
 573         if (aslc_req & ASLC_SET_PWM_FREQ)
 574                 aslc_stat |= asle_set_pwm_freq(dev_priv, asle->pfmb);
 575
 576         if (aslc_req & ASLC_SUPPORTED_ROTATION_ANGLES)
 577                 aslc_stat |= asle_set_supported_rotation_angles(dev_priv,
 578                                                         asle->srot);
 579
 580         if (aslc_req & ASLC_BUTTON_ARRAY)
 581                 aslc_stat |= asle_set_button_array(dev_priv, asle->iuer);
 582
 583         if (aslc_req & ASLC_CONVERTIBLE_INDICATOR)
 584                 aslc_stat |= asle_set_convertible(dev_priv, asle->iuer);
 585
 586         if (aslc_req & ASLC_DOCKING_INDICATOR)
 587                 aslc_stat |= asle_set_docking(dev_priv, asle->iuer);
 588
 589         if (aslc_req & ASLC_ISCT_STATE_CHANGE)
 590                 aslc_stat |= asle_isct_state(dev_priv);
 591
 592         asle->aslc = aslc_stat;
 593 }
 594
 595 void intel_opregion_asle_intr(struct drm_i915_private *dev_priv)
 596 {
 597         if (dev_priv->opregion.asle)
 598                 schedule_work(&dev_priv->opregion.asle_work);
 599 }
 600
 601 #define ACPI_EV_DISPLAY_SWITCH (1<<0)
 602 #define ACPI_EV_LID            (1<<1)
 603 #define ACPI_EV_DOCK           (1<<2)
 604
 605 static struct intel_opregion *system_opregion;
 606
 607 static int intel_opregion_video_event(struct notifier_block *nb,
 608                                       unsigned long val, void *data)
 609 {
 610         /* The only video events relevant to opregion are 0x80. These indicate
 611            either a docking event, lid switch or display switch request. In
 612            Linux, these are handled by the dock, button and video drivers.
 613         */
 614
 615         struct acpi_bus_event *event = data;
 616         struct opregion_acpi *acpi;
 617         int ret = NOTIFY_OK;
 618
 619         if (strcmp(event->device_class, ACPI_VIDEO_CLASS) != 0)
 620                 return NOTIFY_DONE;
 621
 622         if (!system_opregion)
 623                 return NOTIFY_DONE;
 624
 625         acpi = system_opregion->acpi;
 626
 627         if (event->type == 0x80 && ((acpi->cevt & 1) == 0))
 628                 ret = NOTIFY_BAD;
 629
 630         acpi->csts = 0;
 631
 632         return ret;
 633 }
 634
 635 static struct notifier_block intel_opregion_notifier = {
 636         .notifier_call = intel_opregion_video_event,
 637 };
 638
 639 /*
 640  * Initialise the DIDL field in opregion. This passes a list of devices to
 641  * the firmware. Values are defined by section B.4.2 of the ACPI specification
 642  * (version 3)
 643  */
 644
 645 static void set_did(struct intel_opregion *opregion, int i, u32 val)
 646 {
 647         if (i < ARRAY_SIZE(opregion->acpi->didl)) {
 648                 opregion->acpi->didl[i] = val;
 649         } else {
 650                 i -= ARRAY_SIZE(opregion->acpi->didl);
 651
 652                 if (WARN_ON(i >= ARRAY_SIZE(opregion->acpi->did2)))
 653                         return;
 654
 655                 opregion->acpi->did2[i] = val;
 656         }
 657 }
 658
 659 static u32 acpi_display_type(struct intel_connector *connector)
 660 {
 661         u32 display_type;
 662
 663         switch (connector->base.connector_type) {
 664         case DRM_MODE_CONNECTOR_VGA:
 665         case DRM_MODE_CONNECTOR_DVIA:
 666                 display_type = ACPI_DISPLAY_TYPE_VGA;
 667                 break;
 668         case DRM_MODE_CONNECTOR_Composite:
 669         case DRM_MODE_CONNECTOR_SVIDEO:
 670         case DRM_MODE_CONNECTOR_Component:
 671         case DRM_MODE_CONNECTOR_9PinDIN:
 672         case DRM_MODE_CONNECTOR_TV:
 673                 display_type = ACPI_DISPLAY_TYPE_TV;
 674                 break;
 675         case DRM_MODE_CONNECTOR_DVII:
 676         case DRM_MODE_CONNECTOR_DVID:
 677         case DRM_MODE_CONNECTOR_DisplayPort:
 678         case DRM_MODE_CONNECTOR_HDMIA:
 679         case DRM_MODE_CONNECTOR_HDMIB:
 680                 display_type = ACPI_DISPLAY_TYPE_EXTERNAL_DIGITAL;
 681                 break;
 682         case DRM_MODE_CONNECTOR_LVDS:
 683         case DRM_MODE_CONNECTOR_eDP:
 684         case DRM_MODE_CONNECTOR_DSI:
 685                 display_type = ACPI_DISPLAY_TYPE_INTERNAL_DIGITAL;
 686                 break;
 687         case DRM_MODE_CONNECTOR_Unknown:
 688         case DRM_MODE_CONNECTOR_VIRTUAL:
 689                 display_type = ACPI_DISPLAY_TYPE_OTHER;
 690                 break;
 691         default:
 692                 MISSING_CASE(connector->base.connector_type);
 693                 display_type = ACPI_DISPLAY_TYPE_OTHER;
 694                 break;
 695         }
 696
 697         return display_type;
 698 }
 699
 700 static void intel_didl_outputs(struct drm_i915_private *dev_priv)
 701 {
 702         struct intel_opregion *opregion = &dev_priv->opregion;
 703         struct intel_connector *connector;
 704         int i = 0, max_outputs;
 705         int display_index[16] = {};
 706
 707         /*
 708          * In theory, did2, the extended didl, gets added at opregion version
 709          * 3.0. In practice, however, we're supposed to set it for earlier
 710          * versions as well, since a BIOS that doesn't understand did2 should
 711          * not look at it anyway. Use a variable so we can tweak this if a need
 712          * arises later.
 713          */
 714         max_outputs = ARRAY_SIZE(opregion->acpi->didl) +
 715                 ARRAY_SIZE(opregion->acpi->did2);
 716
 717         for_each_intel_connector(&dev_priv->drm, connector) {
 718                 u32 device_id, type;
 719
 720                 device_id = acpi_display_type(connector);
 721
 722                 /* Use display type specific display index. */
 723                 type = (device_id & ACPI_DISPLAY_TYPE_MASK)
 724                         >> ACPI_DISPLAY_TYPE_SHIFT;
 725                 device_id |= display_index[type]++ << ACPI_DISPLAY_INDEX_SHIFT;
 726
 727                 connector->acpi_device_id = device_id;
 728                 if (i < max_outputs)
 729                         set_did(opregion, i, device_id);
 730                 i++;
 731         }
 732
 733         DRM_DEBUG_KMS("%d outputs detected\n", i);
 734
 735         if (i > max_outputs)
 736                 DRM_ERROR("More than %d outputs in connector list\n",
 737                           max_outputs);
 738
 739         /* If fewer than max outputs, the list must be null terminated */
 740         if (i < max_outputs)
 741                 set_did(opregion, i, 0);
 742 }
 743
 744 static void intel_setup_cadls(struct drm_i915_private *dev_priv)
 745 {
 746         struct intel_opregion *opregion = &dev_priv->opregion;
 747         struct intel_connector *connector;
 748         int i = 0;
 749
 750         /*
 751          * Initialize the CADL field from the connector device ids. This is
 752          * essentially the same as copying from the DIDL. Technically, this is
 753          * not always correct as display outputs may exist, but not active. This
 754          * initialization is necessary for some Clevo laptops that check this
 755          * field before processing the brightness and display switching hotkeys.
 756          *
 757          * Note that internal panels should be at the front of the connector
 758          * list already, ensuring they're not left out.
 759          */
 760         for_each_intel_connector(&dev_priv->drm, connector) {
 761                 if (i >= ARRAY_SIZE(opregion->acpi->cadl))
 762                         break;
 763                 opregion->acpi->cadl[i++] = connector->acpi_device_id;
 764         }
 765
 766         /* If fewer than 8 active devices, the list must be null terminated */
 767         if (i < ARRAY_SIZE(opregion->acpi->cadl))
 768                 opregion->acpi->cadl[i] = 0;
 769 }
 770
 771 void intel_opregion_register(struct drm_i915_private *dev_priv)
 772 {
 773         struct intel_opregion *opregion = &dev_priv->opregion;
 774
 775         if (!opregion->header)
 776                 return;
 777
 778         if (opregion->acpi) {
 779                 intel_didl_outputs(dev_priv);
 780                 intel_setup_cadls(dev_priv);
 781
 782                 /* Notify BIOS we are ready to handle ACPI video ext notifs.
 783                  * Right now, all the events are handled by the ACPI video module.
 784                  * We don't actually need to do anything with them. */
 785                 opregion->acpi->csts = 0;
 786                 opregion->acpi->drdy = 1;
 787
 788                 system_opregion = opregion;
 789                 register_acpi_notifier(&intel_opregion_notifier);
 790         }
 791
 792         if (opregion->asle) {
 793                 opregion->asle->tche = ASLE_TCHE_BLC_EN;
 794                 opregion->asle->ardy = ASLE_ARDY_READY;
 795         }
 796 }
 797
 798 void intel_opregion_unregister(struct drm_i915_private *dev_priv)
 799 {
 800         struct intel_opregion *opregion = &dev_priv->opregion;
 801
 802         if (!opregion->header)
 803                 return;
 804
 805         if (opregion->asle)
 806                 opregion->asle->ardy = ASLE_ARDY_NOT_READY;
 807
 808         cancel_work_sync(&dev_priv->opregion.asle_work);
 809
 810         if (opregion->acpi) {
 811                 opregion->acpi->drdy = 0;
 812
 813                 system_opregion = NULL;
 814                 unregister_acpi_notifier(&intel_opregion_notifier);
 815         }
 816
 817         /* just clear all opregion memory pointers now */
 818         memunmap(opregion->header);
 819         if (opregion->rvda) {
 820                 memunmap(opregion->rvda);
 821                 opregion->rvda = NULL;
 822         }
 823         opregion->header = NULL;
 824         opregion->acpi = NULL;
 825         opregion->swsci = NULL;
 826         opregion->asle = NULL;
 827         opregion->vbt = NULL;
 828         opregion->lid_state = NULL;
 829 }
 830
 831 static void swsci_setup(struct drm_i915_private *dev_priv)
 832 {
 833         struct intel_opregion *opregion = &dev_priv->opregion;
 834         bool requested_callbacks = false;
 835         u32 tmp;
 836
 837         /* Sub-function code 0 is okay, let's allow them. */
 838         opregion->swsci_gbda_sub_functions = 1;
 839         opregion->swsci_sbcb_sub_functions = 1;
 840
 841         /* We use GBDA to ask for supported GBDA calls. */
 842         if (swsci(dev_priv, SWSCI_GBDA_SUPPORTED_CALLS, 0, &tmp) == 0) {
 843                 /* make the bits match the sub-function codes */
 844                 tmp <<= 1;
 845                 opregion->swsci_gbda_sub_functions |= tmp;
 846         }
 847
 848         /*
 849          * We also use GBDA to ask for _requested_ SBCB callbacks. The driver
 850          * must not call interfaces that are not specifically requested by the
 851          * bios.
 852          */
 853         if (swsci(dev_priv, SWSCI_GBDA_REQUESTED_CALLBACKS, 0, &tmp) == 0) {
 854                 /* here, the bits already match sub-function codes */
 855                 opregion->swsci_sbcb_sub_functions |= tmp;
 856                 requested_callbacks = true;
 857         }
 858
 859         /*
 860          * But we use SBCB to ask for _supported_ SBCB calls. This does not mean
 861          * the callback is _requested_. But we still can't call interfaces that
 862          * are not requested.
 863          */
 864         if (swsci(dev_priv, SWSCI_SBCB_SUPPORTED_CALLBACKS, 0, &tmp) == 0) {
 865                 /* make the bits match the sub-function codes */
 866                 u32 low = tmp & 0x7ff;
 867                 u32 high = tmp & ~0xfff; /* bit 11 is reserved */
 868                 tmp = (high << 4) | (low << 1) | 1;
 869
 870                 /* best guess what to do with supported wrt requested */
 871                 if (requested_callbacks) {
 872                         u32 req = opregion->swsci_sbcb_sub_functions;
 873                         if ((req & tmp) != req)
 874                                 DRM_DEBUG_DRIVER("SWSCI BIOS requested (%08x) SBCB callbacks that are not supported (%08x)\n", req, tmp);
 875                         /* XXX: for now, trust the requested callbacks */
 876                         /* opregion->swsci_sbcb_sub_functions &= tmp; */
 877                 } else {
 878                         opregion->swsci_sbcb_sub_functions |= tmp;
 879                 }
 880         }
 881
 882         DRM_DEBUG_DRIVER("SWSCI GBDA callbacks %08x, SBCB callbacks %08x\n",
 883                          opregion->swsci_gbda_sub_functions,
 884                          opregion->swsci_sbcb_sub_functions);
 885 }
 886
 887 static int intel_no_opregion_vbt_callback(const struct dmi_system_id *id)
 888 {
 889         DRM_DEBUG_KMS("Falling back to manually reading VBT from "
 890                       "VBIOS ROM for %s\n", id->ident);
 891         return 1;
 892 }
 893
 894 static const struct dmi_system_id intel_no_opregion_vbt[] = {
 895         {
 896                 .callback = intel_no_opregion_vbt_callback,
 897                 .ident = "ThinkCentre A57",
 898                 .matches = {
 899                         DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
 900                         DMI_MATCH(DMI_PRODUCT_NAME, "97027RG"),
 901                 },
 902         },
 903         { }
 904 };
 905
 906 int intel_opregion_setup(struct drm_i915_private *dev_priv)
 907 {
 908         struct intel_opregion *opregion = &dev_priv->opregion;
 909         struct pci_dev *pdev = dev_priv->drm.pdev;
 910         u32 asls, mboxes;
 911         char buf[sizeof(OPREGION_SIGNATURE)];
 912         int err = 0;
 913         void *base;
 914
 915         BUILD_BUG_ON(sizeof(struct opregion_header) != 0x100);
 916         BUILD_BUG_ON(sizeof(struct opregion_acpi) != 0x100);
 917         BUILD_BUG_ON(sizeof(struct opregion_swsci) != 0x100);
 918         BUILD_BUG_ON(sizeof(struct opregion_asle) != 0x100);
 919         BUILD_BUG_ON(sizeof(struct opregion_asle_ext) != 0x400);
 920
 921         pci_read_config_dword(pdev, ASLS, &asls);
 922         DRM_DEBUG_DRIVER("graphic opregion physical addr: 0x%x\n", asls);
 923         if (asls == 0) {
 924                 DRM_DEBUG_DRIVER("ACPI OpRegion not supported!\n");
 925                 return -ENOTSUPP;
 926         }
 927
 928         INIT_WORK(&opregion->asle_work, asle_work);
 929
 930         base = memremap(asls, OPREGION_SIZE, MEMREMAP_WB);
 931         if (!base)
 932                 return -ENOMEM;
 933
 934         memcpy(buf, base, sizeof(buf));
 935
 936         if (memcmp(buf, OPREGION_SIGNATURE, 16)) {
 937                 DRM_DEBUG_DRIVER("opregion signature mismatch\n");
 938                 err = -EINVAL;
 939                 goto err_out;
 940         }
 941         opregion->header = base;
 942         opregion->lid_state = base + ACPI_CLID;
 943
 944         mboxes = opregion->header->mboxes;
 945         if (mboxes & MBOX_ACPI) {
 946                 DRM_DEBUG_DRIVER("Public ACPI methods supported\n");
 947                 opregion->acpi = base + OPREGION_ACPI_OFFSET;
 948         }
 949
 950         if (mboxes & MBOX_SWSCI) {
 951                 DRM_DEBUG_DRIVER("SWSCI supported\n");
 952                 opregion->swsci = base + OPREGION_SWSCI_OFFSET;
 953                 swsci_setup(dev_priv);
 954         }
 955
 956         if (mboxes & MBOX_ASLE) {
 957                 DRM_DEBUG_DRIVER("ASLE supported\n");
 958                 opregion->asle = base + OPREGION_ASLE_OFFSET;
 959
 960                 opregion->asle->ardy = ASLE_ARDY_NOT_READY;
 961         }
 962
 963         if (mboxes & MBOX_ASLE_EXT)
 964                 DRM_DEBUG_DRIVER("ASLE extension supported\n");
 965
 966         if (!dmi_check_system(intel_no_opregion_vbt)) {
 967                 const void *vbt = NULL;
 968                 u32 vbt_size = 0;
 969
 970                 if (opregion->header->opregion_ver >= 2 && opregion->asle &&
 971                     opregion->asle->rvda && opregion->asle->rvds) {
 972                         opregion->rvda = memremap(opregion->asle->rvda,
 973                                                   opregion->asle->rvds,
 974                                                   MEMREMAP_WB);
 975                         vbt = opregion->rvda;
 976                         vbt_size = opregion->asle->rvds;
 977                 }
 978
 979                 if (intel_bios_is_valid_vbt(vbt, vbt_size)) {
 980                         DRM_DEBUG_KMS("Found valid VBT in ACPI OpRegion (RVDA)\n");
 981                         opregion->vbt = vbt;
 982                         opregion->vbt_size = vbt_size;
 983                 } else {
 984                         vbt = base + OPREGION_VBT_OFFSET;
 985                         vbt_size = OPREGION_ASLE_EXT_OFFSET - OPREGION_VBT_OFFSET;
 986                         if (intel_bios_is_valid_vbt(vbt, vbt_size)) {
 987                                 DRM_DEBUG_KMS("Found valid VBT in ACPI OpRegion (Mailbox #4)\n");
 988                                 opregion->vbt = vbt;
 989                                 opregion->vbt_size = vbt_size;
 990                         }
 991                 }
 992         }
 993
 994         return 0;
 995
 996 err_out:
 997         memunmap(base);
 998         return err;
 999 }
1000
1001 static int intel_use_opregion_panel_type_callback(const struct dmi_system_id *id)
1002 {
1003         DRM_INFO("Using panel type from OpRegion on %s\n", id->ident);
1004         return 1;
1005 }
1006
1007 static const struct dmi_system_id intel_use_opregion_panel_type[] = {
1008         {
1009                 .callback = intel_use_opregion_panel_type_callback,
1010                 .ident = "Conrac GmbH IX45GM2",
1011                 .matches = {DMI_MATCH(DMI_SYS_VENDOR, "Conrac GmbH"),
1012                             DMI_MATCH(DMI_PRODUCT_NAME, "IX45GM2"),
1013                 },
1014         },
1015         { }
1016 };
1017
1018 int
1019 intel_opregion_get_panel_type(struct drm_i915_private *dev_priv)
1020 {
1021         u32 panel_details;
1022         int ret;
1023
1024         ret = swsci(dev_priv, SWSCI_GBDA_PANEL_DETAILS, 0x0, &panel_details);
1025         if (ret) {
1026                 DRM_DEBUG_KMS("Failed to get panel details from OpRegion (%d)\n",
1027                               ret);
1028                 return ret;
1029         }
1030
1031         ret = (panel_details >> 8) & 0xff;
1032         if (ret > 0x10) {
1033                 DRM_DEBUG_KMS("Invalid OpRegion panel type 0x%x\n", ret);
1034                 return -EINVAL;
1035         }
1036
1037         /* fall back to VBT panel type? */
1038         if (ret == 0x0) {
1039                 DRM_DEBUG_KMS("No panel type in OpRegion\n");
1040                 return -ENODEV;
1041         }
1042
1043         /*
1044          * So far we know that some machined must use it, others must not use it.
1045          * There doesn't seem to be any way to determine which way to go, except
1046          * via a quirk list :(
1047          */
1048         if (!dmi_check_system(intel_use_opregion_panel_type)) {
1049                 DRM_DEBUG_KMS("Ignoring OpRegion panel type (%d)\n", ret - 1);
1050                 return -ENODEV;
1051         }
1052
1053         /*
1054          * FIXME On Dell XPS 13 9350 the OpRegion panel type (0) gives us
1055          * low vswing for eDP, whereas the VBT panel type (2) gives us normal
1056          * vswing instead. Low vswing results in some display flickers, so
1057          * let's simply ignore the OpRegion panel type on SKL for now.
1058          */
1059         if (IS_SKYLAKE(dev_priv)) {
1060                 DRM_DEBUG_KMS("Ignoring OpRegion panel type (%d)\n", ret - 1);
1061                 return -ENODEV;
1062         }
1063
1064         return ret - 1;
1065 }