On 03/15/2013 06:10 PM, Danny Baumann wrote:
> 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 <dannybaum...@web.de>
> ---
> drivers/acpi/video.c | 52
> +++++++++++++++++++++++++++++++++-------------------
> 1 file changed, 33 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c
> index 5ef329a..8faea35 100644
> --- a/drivers/acpi/video.c
> +++ b/drivers/acpi/video.c
> @@ -450,6 +450,26 @@ 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) {
> + if (device->brightness->flags._BCL_reversed)
> + bqc_value = device->brightness->count - 3 - bqc_value;
> +
> + level = device->brightness->levels[bqc_value + 2];
I don't understand this, what does the +2 have to do here?
_BQC returned us an index, and then we should just convert it to level,
why +2?
The only explanation would be, for BIOS tables that return _BQC as
index, they are indexing from the 3rd entry. Is it the case? If so, I
think we need to put a comment here.
> + } 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 raw)
> @@ -472,14 +492,8 @@ 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;
> @@ -727,24 +741,24 @@ 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) {
> - /*
> - * 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
> - */
> - if (use_bios_initial_backlight) {
-------------------------------------------------------------------
> + if (use_bios_initial_backlight) {
> + if (!br->flags._BQC_use_index) {
> + /*
> + * 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.
> + */
> for (i = 2; i < br->count; i++)
> if (level_old == br->levels[i]) {
> level = level_old;
> break;
> }
> + } else {
> + level = acpi_video_bqc_value_to_level(device,
> + level_old);
What about we convert the value to level first?
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(no matter it is a level, or an
* index.) Set the backlight to max_level in this case.
*/
for (i = 2; i < br->count; i++)
if (level == br->levels[i])
break;
if (i == br->count)
level = max_level;
}
Thanks,
Aaron
> }
> - } else {
> - if (br->flags._BCL_reversed)
> - level_old = (br->count - 1) - level_old;
> - level = br->levels[level_old];
> }
>
> set_level:
>
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