releases/upstream/2.6.30-rc1/0014-thinkpad-acpi-rework-brightness-support.patch

   1 From 0e501834f8c2ba7de2a56e332d346dcf4ac0b593 Mon Sep 17 00:00:00 2001
   2 From: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
   3 Date: Sat, 4 Apr 2009 04:25:53 +0000
   4 Subject: thinkpad-acpi: rework brightness support
   5
   6 Refactor and redesign the brightness control backend...
   7
   8 In order to fix bugzilla #11750...
   9
  10 Add a new brightness control mode: support direct NVRAM checkpointing
  11 of the backlight level (i.e. store directly to NVRAM without the need
  12 for UCMS calls), and use that together with the EC-based control.
  13 Disallow UCMS+EC, thus avoiding races with the SMM firmware.
  14
  15 Switch the models that define HBRV (EC Brightness Value) in the DSDT
  16 to the new mode.  These are: T40-T43, R50-R52, R50e, R51e, X31-X41.
  17
  18 Change the default for all other IBM ThinkPads to UCMS-only.  The
  19 Lenovo models already default to UCMS-only.
  20
  21 Reported-by: Alexey Fisher <bug-track@fisher-privat.net>
  22 Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
  23 Signed-off-by: Len Brown <len.brown@intel.com>
  24 ---
  25  Documentation/laptops/thinkpad-acpi.txt |   12 +-
  26  drivers/platform/x86/thinkpad_acpi.c    |  317 +++++++++++++++++++++----------
  27  2 files changed, 227 insertions(+), 102 deletions(-)
  28
  29 diff --git a/Documentation/laptops/thinkpad-acpi.txt b/Documentation/laptops/thinkpad-acpi.txt
  30 index 25ed43d..3d76507 100644
  31 --- a/Documentation/laptops/thinkpad-acpi.txt
  32 +++ b/Documentation/laptops/thinkpad-acpi.txt
  33 @@ -1157,10 +1157,15 @@ display backlight brightness control methods have 16 levels, ranging
  34  from 0 to 15.
  35
  36  There are two interfaces to the firmware for direct brightness control,
  37 -EC and CMOS.  To select which one should be used, use the
  38 +EC and UCMS (or CMOS).  To select which one should be used, use the
  39  brightness_mode module parameter: brightness_mode=1 selects EC mode,
  40 -brightness_mode=2 selects CMOS mode, brightness_mode=3 selects both EC
  41 -and CMOS.  The driver tries to auto-detect which interface to use.
  42 +brightness_mode=2 selects UCMS mode, brightness_mode=3 selects EC
  43 +mode with NVRAM backing (so that brightness changes are remembered
  44 +across shutdown/reboot).
  45 +
  46 +The driver tries to select which interface to use from a table of
  47 +defaults for each ThinkPad model.  If it makes a wrong choice, please
  48 +report this as a bug, so that we can fix it.
  49
  50  When display backlight brightness controls are available through the
  51  standard ACPI interface, it is best to use it instead of this direct
  52 @@ -1498,6 +1503,7 @@ to enable more than one output class, just add their values.
  53                                 (bluetooth, WWAN, UWB...)
  54         0x0008                  HKEY event interface, hotkeys
  55         0x0010                  Fan control
  56 +       0x0020                  Backlight brightness
  57
  58  There is also a kernel build option to enable more debugging
  59  information, which may be necessary to debug driver problems.
  60 diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
  61 index 4eec770..ba3682c 100644
  62 --- a/drivers/platform/x86/thinkpad_acpi.c
  63 +++ b/drivers/platform/x86/thinkpad_acpi.c
  64 @@ -192,6 +192,7 @@ enum {
  65  #define TPACPI_DBG_RFKILL      0x0004
  66  #define TPACPI_DBG_HKEY                0x0008
  67  #define TPACPI_DBG_FAN         0x0010
  68 +#define TPACPI_DBG_BRGHT       0x0020
  69
  70  #define onoff(status, bit) ((status) & (1 << (bit)) ? "on" : "off")
  71  #define enabled(status, bit) ((status) & (1 << (bit)) ? "enabled" : "disabled")
  72 @@ -274,7 +275,6 @@ static struct {
  73
  74  static struct {
  75         u16 hotkey_mask_ff:1;
  76 -       u16 bright_cmos_ec_unsync:1;
  77  } tp_warned;
  78
  79  struct thinkpad_id_data {
  80 @@ -5526,6 +5526,20 @@ static struct ibm_struct ecdump_driver_data = {
  81
  82  #define TPACPI_BACKLIGHT_DEV_NAME "thinkpad_screen"
  83
  84 +/*
  85 + * ThinkPads can read brightness from two places: EC HBRV (0x31), or
  86 + * CMOS NVRAM byte 0x5E, bits 0-3.
  87 + *
  88 + * EC HBRV (0x31) has the following layout
  89 + *   Bit 7: unknown function
  90 + *   Bit 6: unknown function
  91 + *   Bit 5: Z: honour scale changes, NZ: ignore scale changes
  92 + *   Bit 4: must be set to zero to avoid problems
  93 + *   Bit 3-0: backlight brightness level
  94 + *
  95 + * brightness_get_raw returns status data in the HBRV layout
  96 + */
  97 +
  98  enum {
  99         TP_EC_BACKLIGHT = 0x31,
 100
 101 @@ -5535,108 +5549,164 @@ enum {
 102         TP_EC_BACKLIGHT_MAPSW = 0x20,
 103  };
 104
 105 +enum tpacpi_brightness_access_mode {
 106 +       TPACPI_BRGHT_MODE_AUTO = 0,     /* Not implemented yet */
 107 +       TPACPI_BRGHT_MODE_EC,           /* EC control */
 108 +       TPACPI_BRGHT_MODE_UCMS_STEP,    /* UCMS step-based control */
 109 +       TPACPI_BRGHT_MODE_ECNVRAM,      /* EC control w/ NVRAM store */
 110 +       TPACPI_BRGHT_MODE_MAX
 111 +};
 112 +
 113  static struct backlight_device *ibm_backlight_device;
 114 -static int brightness_mode;
 115 +
 116 +static enum tpacpi_brightness_access_mode brightness_mode =
 117 +               TPACPI_BRGHT_MODE_MAX;
 118 +
 119  static unsigned int brightness_enable = 2; /* 2 = auto, 0 = no, 1 = yes */
 120
 121  static struct mutex brightness_mutex;
 122
 123 -/*
 124 - * ThinkPads can read brightness from two places: EC 0x31, or
 125 - * CMOS NVRAM byte 0x5E, bits 0-3.
 126 - *
 127 - * EC 0x31 has the following layout
 128 - *   Bit 7: unknown function
 129 - *   Bit 6: unknown function
 130 - *   Bit 5: Z: honour scale changes, NZ: ignore scale changes
 131 - *   Bit 4: must be set to zero to avoid problems
 132 - *   Bit 3-0: backlight brightness level
 133 - *
 134 - * brightness_get_raw returns status data in the EC 0x31 layout
 135 - */
 136 -static int brightness_get_raw(int *status)
 137 +/* NVRAM brightness access,
 138 + * call with brightness_mutex held! */
 139 +static unsigned int tpacpi_brightness_nvram_get(void)
 140  {
 141 -       u8 lec = 0, lcmos = 0, level = 0;
 142 +       u8 lnvram;
 143
 144 -       if (brightness_mode & 1) {
 145 -               if (!acpi_ec_read(TP_EC_BACKLIGHT, &lec))
 146 -                       return -EIO;
 147 -               level = lec & TP_EC_BACKLIGHT_LVLMSK;
 148 -       };
 149 -       if (brightness_mode & 2) {
 150 -               lcmos = (nvram_read_byte(TP_NVRAM_ADDR_BRIGHTNESS)
 151 -                        & TP_NVRAM_MASK_LEVEL_BRIGHTNESS)
 152 -                       >> TP_NVRAM_POS_LEVEL_BRIGHTNESS;
 153 -               lcmos &= (tp_features.bright_16levels)? 0x0f : 0x07;
 154 -               level = lcmos;
 155 -       }
 156 -
 157 -       if (brightness_mode == 3) {
 158 -               *status = lec;  /* Prefer EC, CMOS is just a backing store */
 159 -               lec &= TP_EC_BACKLIGHT_LVLMSK;
 160 -               if (lec == lcmos)
 161 -                       tp_warned.bright_cmos_ec_unsync = 0;
 162 -               else {
 163 -                       if (!tp_warned.bright_cmos_ec_unsync) {
 164 -                               printk(TPACPI_ERR
 165 -                                       "CMOS NVRAM (%u) and EC (%u) do not "
 166 -                                       "agree on display brightness level\n",
 167 -                                       (unsigned int) lcmos,
 168 -                                       (unsigned int) lec);
 169 -                               tp_warned.bright_cmos_ec_unsync = 1;
 170 -                       }
 171 +       lnvram = (nvram_read_byte(TP_NVRAM_ADDR_BRIGHTNESS)
 172 +                 & TP_NVRAM_MASK_LEVEL_BRIGHTNESS)
 173 +                 >> TP_NVRAM_POS_LEVEL_BRIGHTNESS;
 174 +       lnvram &= (tp_features.bright_16levels) ? 0x0f : 0x07;
 175 +
 176 +       return lnvram;
 177 +}
 178 +
 179 +static void tpacpi_brightness_checkpoint_nvram(void)
 180 +{
 181 +       u8 lec = 0;
 182 +       u8 b_nvram;
 183 +
 184 +       if (brightness_mode != TPACPI_BRGHT_MODE_ECNVRAM)
 185 +               return;
 186 +
 187 +       vdbg_printk(TPACPI_DBG_BRGHT,
 188 +               "trying to checkpoint backlight level to NVRAM...\n");
 189 +
 190 +       if (mutex_lock_killable(&brightness_mutex) < 0)
 191 +               return;
 192 +
 193 +       if (unlikely(!acpi_ec_read(TP_EC_BACKLIGHT, &lec)))
 194 +               goto unlock;
 195 +       lec &= TP_EC_BACKLIGHT_LVLMSK;
 196 +       b_nvram = nvram_read_byte(TP_NVRAM_ADDR_BRIGHTNESS);
 197 +
 198 +       if (lec != ((b_nvram & TP_NVRAM_MASK_LEVEL_BRIGHTNESS)
 199 +                            >> TP_NVRAM_POS_LEVEL_BRIGHTNESS)) {
 200 +               /* NVRAM needs update */
 201 +               b_nvram &= ~(TP_NVRAM_MASK_LEVEL_BRIGHTNESS <<
 202 +                               TP_NVRAM_POS_LEVEL_BRIGHTNESS);
 203 +               b_nvram |= lec;
 204 +               nvram_write_byte(b_nvram, TP_NVRAM_ADDR_BRIGHTNESS);
 205 +               dbg_printk(TPACPI_DBG_BRGHT,
 206 +                          "updated NVRAM backlight level to %u (0x%02x)\n",
 207 +                          (unsigned int) lec, (unsigned int) b_nvram);
 208 +       } else
 209 +               vdbg_printk(TPACPI_DBG_BRGHT,
 210 +                          "NVRAM backlight level already is %u (0x%02x)\n",
 211 +                          (unsigned int) lec, (unsigned int) b_nvram);
 212 +
 213 +unlock:
 214 +       mutex_unlock(&brightness_mutex);
 215 +}
 216 +
 217 +
 218 +/* call with brightness_mutex held! */
 219 +static int tpacpi_brightness_get_raw(int *status)
 220 +{
 221 +       u8 lec = 0;
 222 +
 223 +       switch (brightness_mode) {
 224 +       case TPACPI_BRGHT_MODE_UCMS_STEP:
 225 +               *status = tpacpi_brightness_nvram_get();
 226 +               return 0;
 227 +       case TPACPI_BRGHT_MODE_EC:
 228 +       case TPACPI_BRGHT_MODE_ECNVRAM:
 229 +               if (unlikely(!acpi_ec_read(TP_EC_BACKLIGHT, &lec)))
 230                         return -EIO;
 231 -               }
 232 -       } else {
 233 -               *status = level;
 234 +               *status = lec;
 235 +               return 0;
 236 +       default:
 237 +               return -ENXIO;
 238         }
 239 +}
 240 +
 241 +/* call with brightness_mutex held! */
 242 +/* do NOT call with illegal backlight level value */
 243 +static int tpacpi_brightness_set_ec(unsigned int value)
 244 +{
 245 +       u8 lec = 0;
 246 +
 247 +       if (unlikely(!acpi_ec_read(TP_EC_BACKLIGHT, &lec)))
 248 +               return -EIO;
 249 +
 250 +       if (unlikely(!acpi_ec_write(TP_EC_BACKLIGHT,
 251 +                               (lec & TP_EC_BACKLIGHT_CMDMSK) |
 252 +                               (value & TP_EC_BACKLIGHT_LVLMSK))))
 253 +               return -EIO;
 254 +
 255 +       return 0;
 256 +}
 257 +
 258 +/* call with brightness_mutex held! */
 259 +static int tpacpi_brightness_set_ucmsstep(unsigned int value)
 260 +{
 261 +       int cmos_cmd, inc;
 262 +       unsigned int current_value, i;
 263 +
 264 +       current_value = tpacpi_brightness_nvram_get();
 265 +
 266 +       if (value == current_value)
 267 +               return 0;
 268 +
 269 +       cmos_cmd = (value > current_value) ?
 270 +                       TP_CMOS_BRIGHTNESS_UP :
 271 +                       TP_CMOS_BRIGHTNESS_DOWN;
 272 +       inc = (value > current_value) ? 1 : -1;
 273 +
 274 +       for (i = current_value; i != value; i += inc)
 275 +               if (issue_thinkpad_cmos_command(cmos_cmd))
 276 +                       return -EIO;
 277
 278         return 0;
 279  }
 280
 281  /* May return EINTR which can always be mapped to ERESTARTSYS */
 282 -static int brightness_set(int value)
 283 +static int brightness_set(unsigned int value)
 284  {
 285 -       int cmos_cmd, inc, i, res;
 286 -       int current_value;
 287 -       int command_bits;
 288 +       int res;
 289
 290         if (value > ((tp_features.bright_16levels)? 15 : 7) ||
 291             value < 0)
 292                 return -EINVAL;
 293
 294 +       vdbg_printk(TPACPI_DBG_BRGHT,
 295 +                       "set backlight level to %d\n", value);
 296 +
 297         res = mutex_lock_killable(&brightness_mutex);
 298         if (res < 0)
 299                 return res;
 300
 301 -       res = brightness_get_raw(&current_value);
 302 -       if (res < 0)
 303 -               goto errout;
 304 -
 305 -       command_bits = current_value & TP_EC_BACKLIGHT_CMDMSK;
 306 -       current_value &= TP_EC_BACKLIGHT_LVLMSK;
 307 -
 308 -       cmos_cmd = value > current_value ?
 309 -                       TP_CMOS_BRIGHTNESS_UP :
 310 -                       TP_CMOS_BRIGHTNESS_DOWN;
 311 -       inc = (value > current_value)? 1 : -1;
 312 -
 313 -       res = 0;
 314 -       for (i = current_value; i != value; i += inc) {
 315 -               if ((brightness_mode & 2) &&
 316 -                   issue_thinkpad_cmos_command(cmos_cmd)) {
 317 -                       res = -EIO;
 318 -                       goto errout;
 319 -               }
 320 -               if ((brightness_mode & 1) &&
 321 -                   !acpi_ec_write(TP_EC_BACKLIGHT,
 322 -                                  (i + inc) | command_bits)) {
 323 -                       res = -EIO;
 324 -                       goto errout;;
 325 -               }
 326 +       switch (brightness_mode) {
 327 +       case TPACPI_BRGHT_MODE_EC:
 328 +       case TPACPI_BRGHT_MODE_ECNVRAM:
 329 +               res = tpacpi_brightness_set_ec(value);
 330 +               break;
 331 +       case TPACPI_BRGHT_MODE_UCMS_STEP:
 332 +               res = tpacpi_brightness_set_ucmsstep(value);
 333 +               break;
 334 +       default:
 335 +               res = -ENXIO;
 336         }
 337
 338 -errout:
 339         mutex_unlock(&brightness_mutex);
 340         return res;
 341  }
 342 @@ -5645,21 +5715,34 @@ errout:
 343
 344  static int brightness_update_status(struct backlight_device *bd)
 345  {
 346 -       /* it is the backlight class's job (caller) to handle
 347 -        * EINTR and other errors properly */
 348 -       return brightness_set(
 349 +       unsigned int level =
 350                 (bd->props.fb_blank == FB_BLANK_UNBLANK &&
 351                  bd->props.power == FB_BLANK_UNBLANK) ?
 352 -                               bd->props.brightness : 0);
 353 +                               bd->props.brightness : 0;
 354 +
 355 +       dbg_printk(TPACPI_DBG_BRGHT,
 356 +                       "backlight: attempt to set level to %d\n",
 357 +                       level);
 358 +
 359 +       /* it is the backlight class's job (caller) to handle
 360 +        * EINTR and other errors properly */
 361 +       return brightness_set(level);
 362  }
 363
 364  static int brightness_get(struct backlight_device *bd)
 365  {
 366         int status, res;
 367
 368 -       res = brightness_get_raw(&status);
 369 +       res = mutex_lock_killable(&brightness_mutex);
 370         if (res < 0)
 371 -               return 0; /* FIXME: teach backlight about error handling */
 372 +               return 0;
 373 +
 374 +       res = tpacpi_brightness_get_raw(&status);
 375 +
 376 +       mutex_unlock(&brightness_mutex);
 377 +
 378 +       if (res < 0)
 379 +               return 0;
 380
 381         return status & TP_EC_BACKLIGHT_LVLMSK;
 382  }
 383 @@ -5709,7 +5792,7 @@ static int __init brightness_init(struct ibm_init_struct *iibm)
 384         }
 385
 386         if (!brightness_enable) {
 387 -               dbg_printk(TPACPI_DBG_INIT,
 388 +               dbg_printk(TPACPI_DBG_INIT | TPACPI_DBG_BRGHT,
 389                            "brightness support disabled by "
 390                            "module parameter\n");
 391                 return 1;
 392 @@ -5724,20 +5807,38 @@ static int __init brightness_init(struct ibm_init_struct *iibm)
 393         if (b == 16)
 394                 tp_features.bright_16levels = 1;
 395
 396 -       if (!brightness_mode) {
 397 -               if (thinkpad_id.vendor == PCI_VENDOR_ID_LENOVO)
 398 -                       brightness_mode = 2;
 399 -               else
 400 -                       brightness_mode = 3;
 401 +       /*
 402 +        * Check for module parameter bogosity, note that we
 403 +        * init brightness_mode to TPACPI_BRGHT_MODE_MAX in order to be
 404 +        * able to detect "unspecified"
 405 +        */
 406 +       if (brightness_mode > TPACPI_BRGHT_MODE_MAX)
 407 +               return -EINVAL;
 408
 409 -               dbg_printk(TPACPI_DBG_INIT, "selected brightness_mode=%d\n",
 410 -                       brightness_mode);
 411 -       }
 412 +       /* TPACPI_BRGHT_MODE_AUTO not implemented yet, just use default */
 413 +       if (brightness_mode == TPACPI_BRGHT_MODE_AUTO ||
 414 +           brightness_mode == TPACPI_BRGHT_MODE_MAX) {
 415 +               if (thinkpad_id.vendor == PCI_VENDOR_ID_IBM) {
 416 +                       /*
 417 +                        * IBM models that define HBRV probably have
 418 +                        * EC-based backlight level control
 419 +                        */
 420 +                       if (acpi_evalf(ec_handle, NULL, "HBRV", "qd"))
 421 +                               /* T40-T43, R50-R52, R50e, R51e, X31-X41 */
 422 +                               brightness_mode = TPACPI_BRGHT_MODE_ECNVRAM;
 423 +                       else
 424 +                               /* all other IBM ThinkPads */
 425 +                               brightness_mode = TPACPI_BRGHT_MODE_UCMS_STEP;
 426 +               } else
 427 +                       /* All Lenovo ThinkPads */
 428 +                       brightness_mode = TPACPI_BRGHT_MODE_UCMS_STEP;
 429
 430 -       if (brightness_mode > 3)
 431 -               return -EINVAL;
 432 +               dbg_printk(TPACPI_DBG_BRGHT,
 433 +                          "selected brightness_mode=%d\n",
 434 +                          brightness_mode);
 435 +       }
 436
 437 -       if (brightness_get_raw(&b) < 0)
 438 +       if (tpacpi_brightness_get_raw(&b) < 0)
 439                 return 1;
 440
 441         if (tp_features.bright_16levels)
 442 @@ -5751,7 +5852,8 @@ static int __init brightness_init(struct ibm_init_struct *iibm)
 443                 printk(TPACPI_ERR "Could not register backlight device\n");
 444                 return PTR_ERR(ibm_backlight_device);
 445         }
 446 -       vdbg_printk(TPACPI_DBG_INIT, "brightness is supported\n");
 447 +       vdbg_printk(TPACPI_DBG_INIT | TPACPI_DBG_BRGHT,
 448 +                       "brightness is supported\n");
 449
 450         ibm_backlight_device->props.max_brightness =
 451                                 (tp_features.bright_16levels)? 15 : 7;
 452 @@ -5761,13 +5863,25 @@ static int __init brightness_init(struct ibm_init_struct *iibm)
 453         return 0;
 454  }
 455
 456 +static void brightness_suspend(pm_message_t state)
 457 +{
 458 +       tpacpi_brightness_checkpoint_nvram();
 459 +}
 460 +
 461 +static void brightness_shutdown(void)
 462 +{
 463 +       tpacpi_brightness_checkpoint_nvram();
 464 +}
 465 +
 466  static void brightness_exit(void)
 467  {
 468         if (ibm_backlight_device) {
 469 -               vdbg_printk(TPACPI_DBG_EXIT,
 470 +               vdbg_printk(TPACPI_DBG_EXIT | TPACPI_DBG_BRGHT,
 471                             "calling backlight_device_unregister()\n");
 472                 backlight_device_unregister(ibm_backlight_device);
 473         }
 474 +
 475 +       tpacpi_brightness_checkpoint_nvram();
 476  }
 477
 478  static int brightness_read(char *p)
 479 @@ -5814,6 +5928,9 @@ static int brightness_write(char *buf)
 480                         return -EINVAL;
 481         }
 482
 483 +       tpacpi_disclose_usertask("procfs brightness",
 484 +                       "set level to %d\n", level);
 485 +
 486         /*
 487          * Now we know what the final level should be, so we try to set it.
 488          * Doing it this way makes the syscall restartable in case of EINTR
 489 @@ -5827,6 +5944,8 @@ static struct ibm_struct brightness_driver_data = {
 490         .read = brightness_read,
 491         .write = brightness_write,
 492         .exit = brightness_exit,
 493 +       .suspend = brightness_suspend,
 494 +       .shutdown = brightness_shutdown,
 495  };
 496
 497  /*************************************************************************
 498 @@ -7465,10 +7584,10 @@ module_param_named(fan_control, fan_control_allowed, bool, 0);
 499  MODULE_PARM_DESC(fan_control,
 500                  "Enables setting fan parameters features when true");
 501
 502 -module_param_named(brightness_mode, brightness_mode, int, 0);
 503 +module_param_named(brightness_mode, brightness_mode, uint, 0);
 504  MODULE_PARM_DESC(brightness_mode,
 505                  "Selects brightness control strategy: "
 506 -                "0=auto, 1=EC, 2=CMOS, 3=both");
 507 +                "0=auto, 1=EC, 2=UCMS, 3=EC+NVRAM");
 508
 509  module_param(brightness_enable, uint, 0);
 510  MODULE_PARM_DESC(brightness_enable,
 511 --
 512 1.6.2.1
 513