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ACPI / video: Fix applying indexed initial brightness value. 

The value initially read via _BQC also needs to be offset by 2 to
compensate for the first 2 special items in _BCL. Introduce a helper
function that does the BQC-value-to-level conversion in order to not
needlessly duplicate code.

Signed-off-by: Danny Baumann <dannybaumann@web.de>
Reviewed-by: Aaron Lu <aaron.lu@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Danny Baumann 2013-03-19 16:22:52 +00:00 committed by Rafael J. Wysocki
parent 2d4128a252
commit 994fa63c5b
1 changed files with 37 additions and 23 deletions
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60
drivers/acpi/video.c
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@ -458,6 +458,31 @@ static struct dmi_system_id video_dmi_table[] __initdata = {
{}
};
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, bool raw)
@ -480,14 +505,8 @@ acpi_video_device_lcd_get_level_current(struct acpi_video_device *device,
return 0;
}
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];
*level = acpi_video_bqc_value_to_level(device, *level);
}
*level += bqc_offset_aml_bug_workaround;
for (i = 2; i < device->brightness->count; i++)
if (device->brightness->levels[i] == *level) {
device->brightness->curr = *level;
@ -736,24 +755,19 @@ acpi_video_init_brightness(struct acpi_video_device *device)
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;
break;
}
}
} else {
if (br->flags._BCL_reversed)
level_old = (br->count - 1) - level_old;
level = br->levels[level_old];
for (i = 2; i < br->count; i++)
if (level_old == br->levels[i])
break;
if (i == br->count)
level = max_level;
}
set_level: