1 files changed, 71 insertions, 39 deletions

diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c
index 313f959413dc..3cdd0471bc63 100644
--- a/drivers/acpi/video.c
+++ b/drivers/acpi/video.c
@@ -222,7 +222,7 @@ static int acpi_video_device_lcd_set_level(struct acpi_video_device *device,
                         int level);
 static int acpi_video_device_lcd_get_level_current(
                         struct acpi_video_device *device,
-                        unsigned long long *level, int init);
+                        unsigned long long *level, bool raw);
 static int acpi_video_get_next_level(struct acpi_video_device *device,
                                      u32 level_current, u32 event);
 static int acpi_video_switch_brightness(struct acpi_video_device *device,
@@ -236,7 +236,7 @@ static int acpi_video_get_brightness(struct backlight_device *bd)
         struct acpi_video_device *vd =
                 (struct acpi_video_device *)bl_get_data(bd);
 
-        if (acpi_video_device_lcd_get_level_current(vd, &cur_level, 0))
+        if (acpi_video_device_lcd_get_level_current(vd, &cur_level, false))
                 return -EINVAL;
         for (i = 2; i < vd->brightness->count; i++) {
                 if (vd->brightness->levels[i] == cur_level)
@@ -281,7 +281,7 @@ static int video_get_cur_state(struct thermal_cooling_device *cooling_dev, unsig
         unsigned long long level;
         int offset;
 
-        if (acpi_video_device_lcd_get_level_current(video, &level, 0))
+        if (acpi_video_device_lcd_get_level_current(video, &level, false))
                 return -EINVAL;
         for (offset = 2; offset < video->brightness->count; offset++)
                 if (level == video->brightness->levels[offset]) {
@@ -447,12 +447,45 @@ static struct dmi_system_id video_dmi_table[] __initdata = {
                 DMI_MATCH(DMI_PRODUCT_NAME, "HP Folio 13 - 2000 Notebook PC"),
                 },
         },
+        {
+         .callback = video_ignore_initial_backlight,
+         .ident = "HP Pavilion dm4",
+         .matches = {
+                DMI_MATCH(DMI_BOARD_VENDOR, "Hewlett-Packard"),
+                DMI_MATCH(DMI_PRODUCT_NAME, "HP Pavilion dm4 Notebook PC"),
+                },
+        },
         {}
 };
 
+static unsigned long long
+acpi_video_bqc_value_to_level(struct acpi_video_device *device,
+                              unsigned long long bqc_value)
+{
+        unsigned long long level;
+
+        if (device->brightness->flags._BQC_use_index) {
+                /*
+                 * _BQC returns an index that doesn't account for
+                 * the first 2 items with special meaning, so we need
+                 * to compensate for that by offsetting ourselves
+                 */
+                if (device->brightness->flags._BCL_reversed)
+                        bqc_value = device->brightness->count - 3 - bqc_value;
+
+                level = device->brightness->levels[bqc_value + 2];
+        } else {
+                level = bqc_value;
+        }
+
+        level += bqc_offset_aml_bug_workaround;
+
+        return level;
+}
+
 static int
 acpi_video_device_lcd_get_level_current(struct acpi_video_device *device,
-                                        unsigned long long *level, int init)
+                                        unsigned long long *level, bool raw)
 {
         acpi_status status = AE_OK;
         int i;
@@ -463,29 +496,30 @@ acpi_video_device_lcd_get_level_current(struct acpi_video_device *device,
                 status = acpi_evaluate_integer(device->dev->handle, buf,
                                                 NULL, level);
                 if (ACPI_SUCCESS(status)) {
-                        if (device->brightness->flags._BQC_use_index) {
-                                if (device->brightness->flags._BCL_reversed)
-                                        *level = device->brightness->count
-                                                                 - 3 - (*level);
-                                *level = device->brightness->levels[*level + 2];
-
+                        if (raw) {
+                                /*
+                                 * Caller has indicated he wants the raw
+                                 * value returned by _BQC, so don't furtherly
+                                 * mess with the value.
+                                 */
+                                return 0;
                         }
-                        *level += bqc_offset_aml_bug_workaround;
+
+                        *level = acpi_video_bqc_value_to_level(device, *level);
+
                         for (i = 2; i < device->brightness->count; i++)
                                 if (device->brightness->levels[i] == *level) {
                                         device->brightness->curr = *level;
                                         return 0;
                         }
-                        if (!init) {
-                                /*
-                                 * BQC returned an invalid level.
-                                 * Stop using it.
-                                 */
-                                ACPI_WARNING((AE_INFO,
-                                              "%s returned an invalid level",
-                                              buf));
-                                device->cap._BQC = device->cap._BCQ = 0;
-                        }
+                        /*
+                         * BQC returned an invalid level.
+                         * Stop using it.
+                         */
+                        ACPI_WARNING((AE_INFO,
+                                      "%s returned an invalid level",
+                                      buf));
+                        device->cap._BQC = device->cap._BCQ = 0;
                 } else {
                         /* Fixme:
                          * should we return an error or ignore this failure?
@@ -703,7 +737,8 @@ acpi_video_init_brightness(struct acpi_video_device *device)
         if (!device->cap._BQC)
                 goto set_level;
 
-        result = acpi_video_device_lcd_get_level_current(device, &level_old, 1);
+        result = acpi_video_device_lcd_get_level_current(device,
+                                                         &level_old, true);
         if (result)
                 goto out_free_levels;
 
@@ -714,31 +749,27 @@ acpi_video_init_brightness(struct acpi_video_device *device)
         if (result)
                 goto out_free_levels;
 
-        result = acpi_video_device_lcd_get_level_current(device, &level, 0);
+        result = acpi_video_device_lcd_get_level_current(device, &level, true);
         if (result)
                 goto out_free_levels;
 
         br->flags._BQC_use_index = (level == max_level ? 0 : 1);
 
-        if (!br->flags._BQC_use_index) {
+        if (use_bios_initial_backlight) {
+                level = acpi_video_bqc_value_to_level(device, level_old);
                 /*
-                 * Set the backlight to the initial state.
-                 * On some buggy laptops, _BQC returns an uninitialized value
-                 * when invoked for the first time, i.e. level_old is invalid.
-                 * set the backlight to max_level in this case
+                 * On some buggy laptops, _BQC returns an uninitialized
+                 * value when invoked for the first time, i.e.
+                 * level_old is invalid (no matter whether it's a level
+                 * or an index). Set the backlight to max_level in this case.
                  */
-                if (use_bios_initial_backlight) {
-                        for (i = 2; i < br->count; i++)
-                                if (level_old == br->levels[i])
-                                        level = level_old;
-                }
-                goto set_level;
+                for (i = 2; i < br->count; i++)
+                        if (level_old == br->levels[i])
+                                break;
+                if (i == br->count)
+                        level = max_level;
         }
 
-        if (br->flags._BCL_reversed)
-                level_old = (br->count - 1) - level_old;
-        level = br->levels[level_old];
-
 set_level:
         result = acpi_video_device_lcd_set_level(device, level);
         if (result)
@@ -1268,7 +1299,8 @@ acpi_video_switch_brightness(struct acpi_video_device *device, int event)
                 goto out;
 
         result = acpi_video_device_lcd_get_level_current(device,
-                                                         &level_current, 0);
+                                                         &level_current,
+                                                         false);
         if (result)
                 goto out;