lkml.org 
[lkml]   [2013]   [Mar]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v2 3/3] ACPI video: Fix applying indexed initial brightness value.
Hi,

>> +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.

Yes, that's the case. The old code did the same thing:

>> - 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);

That's also the reason for the -3 instead of -1 in the BCL_reversed
case. I can add a comment, though.

>> + 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;
> }

That works as well, and looks cleaner to me as well. I'll change that.

Regards,

Danny


\
 
 \ /
  Last update: 2013-03-18 10:21    [W:0.051 / U:0.364 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site