releases/upstream/2.6.24-rc4/0007-ACPI-thinkpad-acpi-fix-brightness_set-error-paths.patch

   1 From 4273af8d08c823d5898a2b1c2d0f25b4a8b9eaee Mon Sep 17 00:00:00 2001
   2 From: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
   3 Date: Tue, 30 Oct 2007 17:46:25 -0200
   4 Subject: [PATCH 22/23] ACPI: thinkpad-acpi: fix brightness_set error paths
   5
   6 The code calling brightness_set() can't handle EINTR/ERESTARTSYS well, nor
   7 is it checking brightness_set() return status properly.
   8
   9 Fix it.
  10
  11 Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
  12 Signed-off-by: Len Brown <len.brown@intel.com>
  13 ---
  14  drivers/misc/thinkpad_acpi.c |   34 +++++++++++++++++++++-------------
  15  1 files changed, 21 insertions(+), 13 deletions(-)
  16
  17 diff --git a/drivers/misc/thinkpad_acpi.c b/drivers/misc/thinkpad_acpi.c
  18 index 306daa5..8c94307 100644
  19 --- a/drivers/misc/thinkpad_acpi.c
  20 +++ b/drivers/misc/thinkpad_acpi.c
  21 @@ -3278,6 +3278,8 @@ static void brightness_exit(void)
  22
  23  static int brightness_update_status(struct backlight_device *bd)
  24  {
  25 +       /* it is the backlight class's job (caller) to handle
  26 +        * EINTR and other errors properly */
  27         return brightness_set(
  28                 (bd->props.fb_blank == FB_BLANK_UNBLANK &&
  29                  bd->props.power == FB_BLANK_UNBLANK) ?
  30 @@ -3318,6 +3320,7 @@ static int brightness_get(struct backlight_device *bd)
  31         return level;
  32  }
  33
  34 +/* May return EINTR which can always be mapped to ERESTARTSYS */
  35  static int brightness_set(int value)
  36  {
  37         int cmos_cmd, inc, i, res;
  38 @@ -3381,29 +3384,34 @@ static int brightness_read(char *p)
  39  static int brightness_write(char *buf)
  40  {
  41         int level;
  42 -       int new_level;
  43 +       int rc;
  44         char *cmd;
  45         int max_level = (tp_features.bright_16levels) ? 15 : 7;
  46
  47 -       while ((cmd = next_cmd(&buf))) {
  48 -               if ((level = brightness_get(NULL)) < 0)
  49 -                       return level;
  50 +       level = brightness_get(NULL);
  51 +       if (level < 0)
  52 +               return level;
  53
  54 +       while ((cmd = next_cmd(&buf))) {
  55                 if (strlencmp(cmd, "up") == 0) {
  56 -                       new_level = level == (max_level)?
  57 -                                               max_level : level + 1;
  58 +                       if (level < max_level)
  59 +                               level++;
  60                 } else if (strlencmp(cmd, "down") == 0) {
  61 -                       new_level = level == 0? 0 : level - 1;
  62 -               } else if (sscanf(cmd, "level %d", &new_level) == 1 &&
  63 -                          new_level >= 0 && new_level <= max_level) {
  64 -                       /* new_level set */
  65 +                       if (level > 0)
  66 +                               level--;
  67 +               } else if (sscanf(cmd, "level %d", &level) == 1 &&
  68 +                          level >= 0 && level <= max_level) {
  69 +                       /* new level set */
  70                 } else
  71                         return -EINVAL;
  72 -
  73 -               brightness_set(new_level);
  74         }
  75
  76 -       return 0;
  77 +       /*
  78 +        * Now we know what the final level should be, so we try to set it.
  79 +        * Doing it this way makes the syscall restartable in case of EINTR
  80 +        */
  81 +       rc = brightness_set(level);
  82 +       return (rc == -EINTR)? ERESTARTSYS : rc;
  83  }
  84
  85  static struct ibm_struct brightness_driver_data = {
  86 --
  87 1.5.3.4
  88