src/patches/suse-2.6.27.39/patches.drivers/dmi-introduce-dmi_first_match

   1 From 2969c7df1c1808d2a38a9adfbb158de7632a0cfb Mon Sep 17 00:00:00 2001
   2 From: Rafael J. Wysocki <rjw@sisk.pl>
   3 Date: Mon, 3 Nov 2008 19:01:03 +0900
   4 Subject: [PATCH] DMI: Introduce dmi_first_match to make the interface more flexible
   5 References: bnc#441721
   6
   7 Some notebooks from HP have the problem that their BIOSes attempt to
   8 spin down hard drives before entering ACPI system states S4 and S5.
   9 This leads to a yo-yo effect during system power-off shutdown and the
  10 last phase of hibernation when the disk is first spun down by the
  11 kernel and then almost immediately turned on and off by the BIOS.
  12 This, in turn, may result in shortening the disk's life times.
  13
  14 To prevent this from happening we can blacklist the affected systems
  15 using DMI information.  However, only the on-board controlles should
  16 be blacklisted and their PCI slot numbers can be used for this
  17 purpose.  Unfortunately the existing interface for checking DMI
  18 information of the system is not very convenient for this purpose,
  19 because to use it, we would have to define special callback functions
  20 or create a separate struct dmi_system_id table for each blacklisted
  21 system.
  22
  23 To overcome this difficulty introduce a new function
  24 dmi_first_match() returning a pointer to the first entry in an array
  25 of struct dmi_system_id elements that matches the system DMI
  26 information.  Then, we can use this pointer to access the entry's
  27 .driver_data field containing the additional information, such as
  28 the PCI slot number, allowing us to do the desired blacklisting.
  29
  30 Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
  31 Signed-off-by: Tejun Heo <tj@kernel.org>
  32 Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
  33 Signed-off-by: Tejun Heo <teheo@suse.de>
  34 ---
  35  drivers/firmware/dmi_scan.c |   68 +++++++++++++++++++++++++++++++++-----------
  36  include/linux/dmi.h         |    3 +
  37  2 files changed, 55 insertions(+), 16 deletions(-)
  38
  39 --- a/drivers/firmware/dmi_scan.c
  40 +++ b/drivers/firmware/dmi_scan.c
  41 @@ -407,6 +407,27 @@ void __init dmi_scan_machine(void)
  42  }
  43
  44  /**
  45 + *     dmi_match - check if dmi_system_id structure matches system DMI data
  46 + *     @dmi: pointer to the dmi_system_id structure to check
  47 + */
  48 +static bool dmi_match(const struct dmi_system_id *dmi)
  49 +{
  50 +       int i;
  51 +
  52 +       for (i = 0; i < ARRAY_SIZE(dmi->matches); i++) {
  53 +               int s = dmi->matches[i].slot;
  54 +               if (s == DMI_NONE)
  55 +                       continue;
  56 +               if (dmi_ident[s]
  57 +                   && strstr(dmi_ident[s], dmi->matches[i].substr))
  58 +                       continue;
  59 +               /* No match */
  60 +               return false;
  61 +       }
  62 +       return true;
  63 +}
  64 +
  65 +/**
  66   *     dmi_check_system - check system DMI data
  67   *     @list: array of dmi_system_id structures to match against
  68   *             All non-null elements of the list must match
  69 @@ -421,30 +442,45 @@ void __init dmi_scan_machine(void)
  70   */
  71  int dmi_check_system(const struct dmi_system_id *list)
  72  {
  73 -       int i, count = 0;
  74 -       const struct dmi_system_id *d = list;
  75 +       int count = 0;
  76 +       const struct dmi_system_id *d;
  77
  78 -       while (d->ident) {
  79 -               for (i = 0; i < ARRAY_SIZE(d->matches); i++) {
  80 -                       int s = d->matches[i].slot;
  81 -                       if (s == DMI_NONE)
  82 -                               continue;
  83 -                       if (dmi_ident[s] && strstr(dmi_ident[s], d->matches[i].substr))
  84 -                               continue;
  85 -                       /* No match */
  86 -                       goto fail;
  87 +       for (d = list; d->ident; d++)
  88 +               if (dmi_match(d)) {
  89 +                       count++;
  90 +                       if (d->callback && d->callback(d))
  91 +                               break;
  92                 }
  93 -               count++;
  94 -               if (d->callback && d->callback(d))
  95 -                       break;
  96 -fail:          d++;
  97 -       }
  98
  99         return count;
 100  }
 101  EXPORT_SYMBOL(dmi_check_system);
 102
 103  /**
 104 + *     dmi_first_match - find dmi_system_id structure matching system DMI data
 105 + *     @list: array of dmi_system_id structures to match against
 106 + *             All non-null elements of the list must match
 107 + *             their slot's (field index's) data (i.e., each
 108 + *             list string must be a substring of the specified
 109 + *             DMI slot's string data) to be considered a
 110 + *             successful match.
 111 + *
 112 + *     Walk the blacklist table until the first match is found.  Return the
 113 + *     pointer to the matching entry or NULL if there's no match.
 114 + */
 115 +const struct dmi_system_id *dmi_first_match(const struct dmi_system_id *list)
 116 +{
 117 +       const struct dmi_system_id *d;
 118 +
 119 +       for (d = list; d->ident; d++)
 120 +               if (dmi_match(d))
 121 +                       return d;
 122 +
 123 +       return NULL;
 124 +}
 125 +EXPORT_SYMBOL(dmi_first_match);
 126 +
 127 +/**
 128   *     dmi_get_system_info - return DMI data value
 129   *     @field: data index (see enum dmi_field)
 130   *
 131 --- a/include/linux/dmi.h
 132 +++ b/include/linux/dmi.h
 133 @@ -75,6 +75,7 @@ struct dmi_device {
 134  #ifdef CONFIG_DMI
 135
 136  extern int dmi_check_system(const struct dmi_system_id *list);
 137 +const struct dmi_system_id *dmi_first_match(const struct dmi_system_id *list);
 138  extern const char * dmi_get_system_info(int field);
 139  extern const struct dmi_device * dmi_find_device(int type, const char *name,
 140         const struct dmi_device *from);
 141 @@ -88,6 +89,8 @@ extern int dmi_walk(void (*decode)(const
 142  #else
 143
 144  static inline int dmi_check_system(const struct dmi_system_id *list) { return 0; }
 145 +static inline const struct dmi_system_id *dmi_first_match(const struct dmi_system_id *list)
 146 +       { return NULL; }
 147  static inline const char * dmi_get_system_info(int field) { return NULL; }
 148  static inline const struct dmi_device * dmi_find_device(int type, const char *name,
 149         const struct dmi_device *from) { return NULL; }