Re: Question about ACPI Video

[Zhang Rui <rui.zhang@intel.com>]

On Mon, 2010-01-25 at 17:45 +0800, luke lin wrote:
> Hi all,
> 
> I read the drivers/acpi/video.c:
> 
> 895         result = acpi_video_device_lcd_set_level(device, max_level);
> 896         if (result)
> 897                 goto out_free_levels;
> 898
> 899         result = acpi_video_device_lcd_get_level_current(device, &level);
> 900         if (result)
> 901                 goto out_free_levels;
> 902
> 903         br->flags._BQC_use_index = (level == max_level ? 0 : 1);
> 904
> 905         if (!br->flags._BQC_use_index) {
> 912                 for (i = 2; i < br->count; i++)
> 913                         if (level_old == br->levels[i])
> 914                                 level = level_old;
> 915                 goto set_level;
> 916         }
> why after level == max_level, it will still need set_level again?
> is this a bug, or it is necessary.
> 
Because setting the backlight to max_level is just to check if _BQC uses
indexed value. We need to set the backlight back after this is done.

thanks,
rui


> thx
> luke
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