git.oblomov.eu Git - linux-2.6/blob - drivers/ide/ide-acpi.c

   1 /*
   2  * Provides ACPI support for IDE drives.
   3  *
   4  * Copyright (C) 2005 Intel Corp.
   5  * Copyright (C) 2005 Randy Dunlap
   6  * Copyright (C) 2006 SUSE Linux Products GmbH
   7  * Copyright (C) 2006 Hannes Reinecke
   8  */
   9
  10 #include <linux/ata.h>
  11 #include <linux/delay.h>
  12 #include <linux/device.h>
  13 #include <linux/errno.h>
  14 #include <linux/kernel.h>
  15 #include <acpi/acpi.h>
  16 #include <linux/ide.h>
  17 #include <linux/pci.h>
  18 #include <linux/dmi.h>
  19
  20 #include <acpi/acpi_bus.h>
  21
  22 #define REGS_PER_GTF            7
  23
  24 struct GTM_buffer {
  25         u32     PIO_speed0;
  26         u32     DMA_speed0;
  27         u32     PIO_speed1;
  28         u32     DMA_speed1;
  29         u32     GTM_flags;
  30 };
  31
  32 struct ide_acpi_drive_link {
  33         acpi_handle      obj_handle;
  34         u8               idbuff[512];
  35 };
  36
  37 struct ide_acpi_hwif_link {
  38         ide_hwif_t                      *hwif;
  39         acpi_handle                      obj_handle;
  40         struct GTM_buffer                gtm;
  41         struct ide_acpi_drive_link       master;
  42         struct ide_acpi_drive_link       slave;
  43 };
  44
  45 #undef DEBUGGING
  46 /* note: adds function name and KERN_DEBUG */
  47 #ifdef DEBUGGING
  48 #define DEBPRINT(fmt, args...)  \
  49                 printk(KERN_DEBUG "%s: " fmt, __func__, ## args)
  50 #else
  51 #define DEBPRINT(fmt, args...)  do {} while (0)
  52 #endif  /* DEBUGGING */
  53
  54 static int ide_noacpi;
  55 module_param_named(noacpi, ide_noacpi, bool, 0);
  56 MODULE_PARM_DESC(noacpi, "disable IDE ACPI support");
  57
  58 static int ide_acpigtf;
  59 module_param_named(acpigtf, ide_acpigtf, bool, 0);
  60 MODULE_PARM_DESC(acpigtf, "enable IDE ACPI _GTF support");
  61
  62 static int ide_acpionboot;
  63 module_param_named(acpionboot, ide_acpionboot, bool, 0);
  64 MODULE_PARM_DESC(acpionboot, "call IDE ACPI methods on boot");
  65
  66 static bool ide_noacpi_psx;
  67 static int no_acpi_psx(const struct dmi_system_id *id)
  68 {
  69         ide_noacpi_psx = true;
  70         printk(KERN_NOTICE"%s detected - disable ACPI _PSx.\n", id->ident);
  71         return 0;
  72 }
  73
  74 static const struct dmi_system_id ide_acpi_dmi_table[] = {
  75         /* Bug 9673. */
  76         /* We should check if this is because ACPI NVS isn't save/restored. */
  77         {
  78                 .callback = no_acpi_psx,
  79                 .ident    = "HP nx9005",
  80                 .matches  = {
  81                         DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies Ltd."),
  82                         DMI_MATCH(DMI_BIOS_VERSION, "KAM1.60")
  83                 },
  84         },
  85
  86         { }     /* terminate list */
  87 };
  88
  89 int ide_acpi_init(void)
  90 {
  91         dmi_check_system(ide_acpi_dmi_table);
  92         return 0;
  93 }
  94
  95 /**
  96  * ide_get_dev_handle - finds acpi_handle and PCI device.function
  97  * @dev: device to locate
  98  * @handle: returned acpi_handle for @dev
  99  * @pcidevfn: return PCI device.func for @dev
 100  *
 101  * Returns the ACPI object handle to the corresponding PCI device.
 102  *
 103  * Returns 0 on success, <0 on error.
 104  */
 105 static int ide_get_dev_handle(struct device *dev, acpi_handle *handle,
 106                                acpi_integer *pcidevfn)
 107 {
 108         struct pci_dev *pdev = to_pci_dev(dev);
 109         unsigned int bus, devnum, func;
 110         acpi_integer addr;
 111         acpi_handle dev_handle;
 112         struct acpi_buffer buffer = {.length = ACPI_ALLOCATE_BUFFER,
 113                                         .pointer = NULL};
 114         acpi_status status;
 115         struct acpi_device_info *dinfo = NULL;
 116         int ret = -ENODEV;
 117
 118         bus = pdev->bus->number;
 119         devnum = PCI_SLOT(pdev->devfn);
 120         func = PCI_FUNC(pdev->devfn);
 121         /* ACPI _ADR encoding for PCI bus: */
 122         addr = (acpi_integer)(devnum << 16 | func);
 123
 124         DEBPRINT("ENTER: pci %02x:%02x.%01x\n", bus, devnum, func);
 125
 126         dev_handle = DEVICE_ACPI_HANDLE(dev);
 127         if (!dev_handle) {
 128                 DEBPRINT("no acpi handle for device\n");
 129                 goto err;
 130         }
 131
 132         status = acpi_get_object_info(dev_handle, &buffer);
 133         if (ACPI_FAILURE(status)) {
 134                 DEBPRINT("get_object_info for device failed\n");
 135                 goto err;
 136         }
 137         dinfo = buffer.pointer;
 138         if (dinfo && (dinfo->valid & ACPI_VALID_ADR) &&
 139             dinfo->address == addr) {
 140                 *pcidevfn = addr;
 141                 *handle = dev_handle;
 142         } else {
 143                 DEBPRINT("get_object_info for device has wrong "
 144                         " address: %llu, should be %u\n",
 145                         dinfo ? (unsigned long long)dinfo->address : -1ULL,
 146                         (unsigned int)addr);
 147                 goto err;
 148         }
 149
 150         DEBPRINT("for dev=0x%x.%x, addr=0x%llx, *handle=0x%p\n",
 151                  devnum, func, (unsigned long long)addr, *handle);
 152         ret = 0;
 153 err:
 154         kfree(dinfo);
 155         return ret;
 156 }
 157
 158 /**
 159  * ide_acpi_hwif_get_handle - Get ACPI object handle for a given hwif
 160  * @hwif: device to locate
 161  *
 162  * Retrieves the object handle for a given hwif.
 163  *
 164  * Returns handle on success, 0 on error.
 165  */
 166 static acpi_handle ide_acpi_hwif_get_handle(ide_hwif_t *hwif)
 167 {
 168         struct device           *dev = hwif->gendev.parent;
 169         acpi_handle             uninitialized_var(dev_handle);
 170         acpi_integer            pcidevfn;
 171         acpi_handle             chan_handle;
 172         int                     err;
 173
 174         DEBPRINT("ENTER: device %s\n", hwif->name);
 175
 176         if (!dev) {
 177                 DEBPRINT("no PCI device for %s\n", hwif->name);
 178                 return NULL;
 179         }
 180
 181         err = ide_get_dev_handle(dev, &dev_handle, &pcidevfn);
 182         if (err < 0) {
 183                 DEBPRINT("ide_get_dev_handle failed (%d)\n", err);
 184                 return NULL;
 185         }
 186
 187         /* get child objects of dev_handle == channel objects,
 188          * + _their_ children == drive objects */
 189         /* channel is hwif->channel */
 190         chan_handle = acpi_get_child(dev_handle, hwif->channel);
 191         DEBPRINT("chan adr=%d: handle=0x%p\n",
 192                  hwif->channel, chan_handle);
 193
 194         return chan_handle;
 195 }
 196
 197 /**
 198  * do_drive_get_GTF - get the drive bootup default taskfile settings
 199  * @drive: the drive for which the taskfile settings should be retrieved
 200  * @gtf_length: number of bytes of _GTF data returned at @gtf_address
 201  * @gtf_address: buffer containing _GTF taskfile arrays
 202  *
 203  * The _GTF method has no input parameters.
 204  * It returns a variable number of register set values (registers
 205  * hex 1F1..1F7, taskfiles).
 206  * The <variable number> is not known in advance, so have ACPI-CA
 207  * allocate the buffer as needed and return it, then free it later.
 208  *
 209  * The returned @gtf_length and @gtf_address are only valid if the
 210  * function return value is 0.
 211  */
 212 static int do_drive_get_GTF(ide_drive_t *drive,
 213                      unsigned int *gtf_length, unsigned long *gtf_address,
 214                      unsigned long *obj_loc)
 215 {
 216         acpi_status                     status;
 217         struct acpi_buffer              output;
 218         union acpi_object               *out_obj;
 219         int                             err = -ENODEV;
 220
 221         *gtf_length = 0;
 222         *gtf_address = 0UL;
 223         *obj_loc = 0UL;
 224
 225         if (!drive->acpidata->obj_handle) {
 226                 DEBPRINT("No ACPI object found for %s\n", drive->name);
 227                 goto out;
 228         }
 229
 230         /* Setting up output buffer */
 231         output.length = ACPI_ALLOCATE_BUFFER;
 232         output.pointer = NULL;  /* ACPI-CA sets this; save/free it later */
 233
 234         /* _GTF has no input parameters */
 235         err = -EIO;
 236         status = acpi_evaluate_object(drive->acpidata->obj_handle, "_GTF",
 237                                       NULL, &output);
 238         if (ACPI_FAILURE(status)) {
 239                 printk(KERN_DEBUG
 240                        "%s: Run _GTF error: status = 0x%x\n",
 241                        __func__, status);
 242                 goto out;
 243         }
 244
 245         if (!output.length || !output.pointer) {
 246                 DEBPRINT("Run _GTF: "
 247                        "length or ptr is NULL (0x%llx, 0x%p)\n",
 248                        (unsigned long long)output.length,
 249                        output.pointer);
 250                 goto out;
 251         }
 252
 253         out_obj = output.pointer;
 254         if (out_obj->type != ACPI_TYPE_BUFFER) {
 255                 DEBPRINT("Run _GTF: error: "
 256                        "expected object type of ACPI_TYPE_BUFFER, "
 257                        "got 0x%x\n", out_obj->type);
 258                 err = -ENOENT;
 259                 kfree(output.pointer);
 260                 goto out;
 261         }
 262
 263         if (!out_obj->buffer.length || !out_obj->buffer.pointer ||
 264             out_obj->buffer.length % REGS_PER_GTF) {
 265                 printk(KERN_ERR
 266                        "%s: unexpected GTF length (%d) or addr (0x%p)\n",
 267                        __func__, out_obj->buffer.length,
 268                        out_obj->buffer.pointer);
 269                 err = -ENOENT;
 270                 kfree(output.pointer);
 271                 goto out;
 272         }
 273
 274         *gtf_length = out_obj->buffer.length;
 275         *gtf_address = (unsigned long)out_obj->buffer.pointer;
 276         *obj_loc = (unsigned long)out_obj;
 277         DEBPRINT("returning gtf_length=%d, gtf_address=0x%lx, obj_loc=0x%lx\n",
 278                  *gtf_length, *gtf_address, *obj_loc);
 279         err = 0;
 280 out:
 281         return err;
 282 }
 283
 284 /**
 285  * do_drive_set_taskfiles - write the drive taskfile settings from _GTF
 286  * @drive: the drive to which the taskfile command should be sent
 287  * @gtf_length: total number of bytes of _GTF taskfiles
 288  * @gtf_address: location of _GTF taskfile arrays
 289  *
 290  * Write {gtf_address, length gtf_length} in groups of
 291  * REGS_PER_GTF bytes.
 292  */
 293 static int do_drive_set_taskfiles(ide_drive_t *drive,
 294                                   unsigned int gtf_length,
 295                                   unsigned long gtf_address)
 296 {
 297         int                     rc = 0, err;
 298         int                     gtf_count = gtf_length / REGS_PER_GTF;
 299         int                     ix;
 300
 301         DEBPRINT("total GTF bytes=%u (0x%x), gtf_count=%d, addr=0x%lx\n",
 302                  gtf_length, gtf_length, gtf_count, gtf_address);
 303
 304         /* send all taskfile registers (0x1f1-0x1f7) *in*that*order* */
 305         for (ix = 0; ix < gtf_count; ix++) {
 306                 u8 *gtf = (u8 *)(gtf_address + ix * REGS_PER_GTF);
 307                 struct ide_cmd cmd;
 308
 309                 DEBPRINT("(0x1f1-1f7): "
 310                          "hex: %02x %02x %02x %02x %02x %02x %02x\n",
 311                          gtf[0], gtf[1], gtf[2],
 312                          gtf[3], gtf[4], gtf[5], gtf[6]);
 313
 314                 if (!ide_acpigtf) {
 315                         DEBPRINT("_GTF execution disabled\n");
 316                         continue;
 317                 }
 318
 319                 /* convert GTF to taskfile */
 320                 memset(&cmd, 0, sizeof(cmd));
 321                 memcpy(&cmd.tf_array[7], gtf, REGS_PER_GTF);
 322                 cmd.tf_flags = IDE_TFLAG_TF | IDE_TFLAG_DEVICE;
 323
 324                 err = ide_no_data_taskfile(drive, &cmd);
 325                 if (err) {
 326                         printk(KERN_ERR "%s: ide_no_data_taskfile failed: %u\n",
 327                                         __func__, err);
 328                         rc = err;
 329                 }
 330         }
 331
 332         return rc;
 333 }
 334
 335 /**
 336  * ide_acpi_exec_tfs - get then write drive taskfile settings
 337  * @drive: the drive for which the taskfile settings should be
 338  *         written.
 339  *
 340  * According to the ACPI spec this should be called after _STM
 341  * has been evaluated for the interface. Some ACPI vendors interpret
 342  * that as a hard requirement and modify the taskfile according
 343  * to the Identify Drive information passed down with _STM.
 344  * So one should really make sure to call this only after _STM has
 345  * been executed.
 346  */
 347 int ide_acpi_exec_tfs(ide_drive_t *drive)
 348 {
 349         int             ret;
 350         unsigned int    gtf_length;
 351         unsigned long   gtf_address;
 352         unsigned long   obj_loc;
 353
 354         if (ide_noacpi)
 355                 return 0;
 356
 357         DEBPRINT("call get_GTF, drive=%s port=%d\n", drive->name, drive->dn);
 358
 359         ret = do_drive_get_GTF(drive, &gtf_length, &gtf_address, &obj_loc);
 360         if (ret < 0) {
 361                 DEBPRINT("get_GTF error (%d)\n", ret);
 362                 return ret;
 363         }
 364
 365         DEBPRINT("call set_taskfiles, drive=%s\n", drive->name);
 366
 367         ret = do_drive_set_taskfiles(drive, gtf_length, gtf_address);
 368         kfree((void *)obj_loc);
 369         if (ret < 0) {
 370                 DEBPRINT("set_taskfiles error (%d)\n", ret);
 371         }
 372
 373         DEBPRINT("ret=%d\n", ret);
 374
 375         return ret;
 376 }
 377
 378 /**
 379  * ide_acpi_get_timing - get the channel (controller) timings
 380  * @hwif: target IDE interface (channel)
 381  *
 382  * This function executes the _GTM ACPI method for the target channel.
 383  *
 384  */
 385 void ide_acpi_get_timing(ide_hwif_t *hwif)
 386 {
 387         acpi_status             status;
 388         struct acpi_buffer      output;
 389         union acpi_object       *out_obj;
 390
 391         if (ide_noacpi)
 392                 return;
 393
 394         DEBPRINT("ENTER:\n");
 395
 396         if (!hwif->acpidata) {
 397                 DEBPRINT("no ACPI data for %s\n", hwif->name);
 398                 return;
 399         }
 400
 401         /* Setting up output buffer for _GTM */
 402         output.length = ACPI_ALLOCATE_BUFFER;
 403         output.pointer = NULL;  /* ACPI-CA sets this; save/free it later */
 404
 405         /* _GTM has no input parameters */
 406         status = acpi_evaluate_object(hwif->acpidata->obj_handle, "_GTM",
 407                                       NULL, &output);
 408
 409         DEBPRINT("_GTM status: %d, outptr: 0x%p, outlen: 0x%llx\n",
 410                  status, output.pointer,
 411                  (unsigned long long)output.length);
 412
 413         if (ACPI_FAILURE(status)) {
 414                 DEBPRINT("Run _GTM error: status = 0x%x\n", status);
 415                 return;
 416         }
 417
 418         if (!output.length || !output.pointer) {
 419                 DEBPRINT("Run _GTM: length or ptr is NULL (0x%llx, 0x%p)\n",
 420                        (unsigned long long)output.length,
 421                        output.pointer);
 422                 kfree(output.pointer);
 423                 return;
 424         }
 425
 426         out_obj = output.pointer;
 427         if (out_obj->type != ACPI_TYPE_BUFFER) {
 428                 kfree(output.pointer);
 429                 DEBPRINT("Run _GTM: error: "
 430                        "expected object type of ACPI_TYPE_BUFFER, "
 431                        "got 0x%x\n", out_obj->type);
 432                 return;
 433         }
 434
 435         if (!out_obj->buffer.length || !out_obj->buffer.pointer ||
 436             out_obj->buffer.length != sizeof(struct GTM_buffer)) {
 437                 kfree(output.pointer);
 438                 printk(KERN_ERR
 439                         "%s: unexpected _GTM length (0x%x)[should be 0x%zx] or "
 440                         "addr (0x%p)\n",
 441                         __func__, out_obj->buffer.length,
 442                         sizeof(struct GTM_buffer), out_obj->buffer.pointer);
 443                 return;
 444         }
 445
 446         memcpy(&hwif->acpidata->gtm, out_obj->buffer.pointer,
 447                sizeof(struct GTM_buffer));
 448
 449         DEBPRINT("_GTM info: ptr: 0x%p, len: 0x%x, exp.len: 0x%Zx\n",
 450                  out_obj->buffer.pointer, out_obj->buffer.length,
 451                  sizeof(struct GTM_buffer));
 452
 453         DEBPRINT("_GTM fields: 0x%x, 0x%x, 0x%x, 0x%x, 0x%x\n",
 454                  hwif->acpidata->gtm.PIO_speed0,
 455                  hwif->acpidata->gtm.DMA_speed0,
 456                  hwif->acpidata->gtm.PIO_speed1,
 457                  hwif->acpidata->gtm.DMA_speed1,
 458                  hwif->acpidata->gtm.GTM_flags);
 459
 460         kfree(output.pointer);
 461 }
 462
 463 /**
 464  * ide_acpi_push_timing - set the channel (controller) timings
 465  * @hwif: target IDE interface (channel)
 466  *
 467  * This function executes the _STM ACPI method for the target channel.
 468  *
 469  * _STM requires Identify Drive data, which has to passed as an argument.
 470  * Unfortunately drive->id is a mangled version which we can't readily
 471  * use; hence we'll get the information afresh.
 472  */
 473 void ide_acpi_push_timing(ide_hwif_t *hwif)
 474 {
 475         acpi_status             status;
 476         struct acpi_object_list input;
 477         union acpi_object       in_params[3];
 478         struct ide_acpi_drive_link      *master = &hwif->acpidata->master;
 479         struct ide_acpi_drive_link      *slave = &hwif->acpidata->slave;
 480
 481         if (ide_noacpi)
 482                 return;
 483
 484         DEBPRINT("ENTER:\n");
 485
 486         if (!hwif->acpidata) {
 487                 DEBPRINT("no ACPI data for %s\n", hwif->name);
 488                 return;
 489         }
 490
 491         /* Give the GTM buffer + drive Identify data to the channel via the
 492          * _STM method: */
 493         /* setup input parameters buffer for _STM */
 494         input.count = 3;
 495         input.pointer = in_params;
 496         in_params[0].type = ACPI_TYPE_BUFFER;
 497         in_params[0].buffer.length = sizeof(struct GTM_buffer);
 498         in_params[0].buffer.pointer = (u8 *)&hwif->acpidata->gtm;
 499         in_params[1].type = ACPI_TYPE_BUFFER;
 500         in_params[1].buffer.length = ATA_ID_WORDS * 2;
 501         in_params[1].buffer.pointer = (u8 *)&master->idbuff;
 502         in_params[2].type = ACPI_TYPE_BUFFER;
 503         in_params[2].buffer.length = ATA_ID_WORDS * 2;
 504         in_params[2].buffer.pointer = (u8 *)&slave->idbuff;
 505         /* Output buffer: _STM has no output */
 506
 507         status = acpi_evaluate_object(hwif->acpidata->obj_handle, "_STM",
 508                                       &input, NULL);
 509
 510         if (ACPI_FAILURE(status)) {
 511                 DEBPRINT("Run _STM error: status = 0x%x\n", status);
 512         }
 513         DEBPRINT("_STM status: %d\n", status);
 514 }
 515
 516 /**
 517  * ide_acpi_set_state - set the channel power state
 518  * @hwif: target IDE interface
 519  * @on: state, on/off
 520  *
 521  * This function executes the _PS0/_PS3 ACPI method to set the power state.
 522  * ACPI spec requires _PS0 when IDE power on and _PS3 when power off
 523  */
 524 void ide_acpi_set_state(ide_hwif_t *hwif, int on)
 525 {
 526         ide_drive_t *drive;
 527         int i;
 528
 529         if (ide_noacpi || ide_noacpi_psx)
 530                 return;
 531
 532         DEBPRINT("ENTER:\n");
 533
 534         if (!hwif->acpidata) {
 535                 DEBPRINT("no ACPI data for %s\n", hwif->name);
 536                 return;
 537         }
 538
 539         /* channel first and then drives for power on and verse versa for power off */
 540         if (on)
 541                 acpi_bus_set_power(hwif->acpidata->obj_handle, ACPI_STATE_D0);
 542
 543         ide_port_for_each_present_dev(i, drive, hwif) {
 544                 if (drive->acpidata->obj_handle)
 545                         acpi_bus_set_power(drive->acpidata->obj_handle,
 546                                            on ? ACPI_STATE_D0 : ACPI_STATE_D3);
 547         }
 548
 549         if (!on)
 550                 acpi_bus_set_power(hwif->acpidata->obj_handle, ACPI_STATE_D3);
 551 }
 552
 553 /**
 554  * ide_acpi_init_port - initialize the ACPI link for an IDE interface
 555  * @hwif: target IDE interface (channel)
 556  *
 557  * The ACPI spec is not quite clear when the drive identify buffer
 558  * should be obtained. Calling IDENTIFY DEVICE during shutdown
 559  * is not the best of ideas as the drive might already being put to
 560  * sleep. And obviously we can't call it during resume.
 561  * So we get the information during startup; but this means that
 562  * any changes during run-time will be lost after resume.
 563  */
 564 void ide_acpi_init_port(ide_hwif_t *hwif)
 565 {
 566         hwif->acpidata = kzalloc(sizeof(struct ide_acpi_hwif_link), GFP_KERNEL);
 567         if (!hwif->acpidata)
 568                 return;
 569
 570         hwif->acpidata->obj_handle = ide_acpi_hwif_get_handle(hwif);
 571         if (!hwif->acpidata->obj_handle) {
 572                 DEBPRINT("no ACPI object for %s found\n", hwif->name);
 573                 kfree(hwif->acpidata);
 574                 hwif->acpidata = NULL;
 575         }
 576 }
 577
 578 void ide_acpi_port_init_devices(ide_hwif_t *hwif)
 579 {
 580         ide_drive_t *drive;
 581         int i, err;
 582
 583         if (hwif->acpidata == NULL)
 584                 return;
 585
 586         /*
 587          * The ACPI spec mandates that we send information
 588          * for both drives, regardless whether they are connected
 589          * or not.
 590          */
 591         hwif->devices[0]->acpidata = &hwif->acpidata->master;
 592         hwif->devices[1]->acpidata = &hwif->acpidata->slave;
 593
 594         /* get _ADR info for each device */
 595         ide_port_for_each_present_dev(i, drive, hwif) {
 596                 acpi_handle dev_handle;
 597
 598                 DEBPRINT("ENTER: %s at channel#: %d port#: %d\n",
 599                          drive->name, hwif->channel, drive->dn & 1);
 600
 601                 /* TBD: could also check ACPI object VALID bits */
 602                 dev_handle = acpi_get_child(hwif->acpidata->obj_handle,
 603                                             drive->dn & 1);
 604
 605                 DEBPRINT("drive %s handle 0x%p\n", drive->name, dev_handle);
 606
 607                 drive->acpidata->obj_handle = dev_handle;
 608         }
 609
 610         /* send IDENTIFY for each device */
 611         ide_port_for_each_present_dev(i, drive, hwif) {
 612                 err = taskfile_lib_get_identify(drive, drive->acpidata->idbuff);
 613                 if (err)
 614                         DEBPRINT("identify device %s failed (%d)\n",
 615                                  drive->name, err);
 616         }
 617
 618         if (!ide_acpionboot) {
 619                 DEBPRINT("ACPI methods disabled on boot\n");
 620                 return;
 621         }
 622
 623         /* ACPI _PS0 before _STM */
 624         ide_acpi_set_state(hwif, 1);
 625         /*
 626          * ACPI requires us to call _STM on startup
 627          */
 628         ide_acpi_get_timing(hwif);
 629         ide_acpi_push_timing(hwif);
 630
 631         ide_port_for_each_present_dev(i, drive, hwif) {
 632                 ide_acpi_exec_tfs(drive);
 633         }
 634 }