[maemo-developers] [maemo-developers] Re: backlight

[From: Brad Midgley]

Arnaud

The strange thing is that when you're on the lowest level the gui will
allow (1), the display goes a little dimmer than that when idle and the
sys file actually reports the value 0. But if you *write* a 0 to the sys
file, the backlight turns off altogether.

This leaves two interpretations for a 0 value.

Brad

>>Looks like it can be controlled via ioctl on the framebuffer device.
>>http://maemo.org/lxr/source/osso-af-utils/src/omapfb.h
>>
>>struct lcd_panel has pointer
>>int (*set_bklight_level)(struct lcd_panel *panel,unsigned int level);
>>
>>I'll try to figure out how it can be called. If anyone knows, don't
>>hesitate to answer :)
> 
> 
> well, you can call it by echoing to
> /sys/bus/platform/devices/omapfb/panel/backlight_level
> 
> In reality, the function called is lph8923_panel_set_bklight_level() in
> lcd_lph8923.c (which in turn calls tahvo_set_backlight_level). The code
> is saying that 1 is the lowest value (except 0 :P) and 15 the highest.
> 
> So, you can't go lower unless there's an other way to play with the
> level.
> 
> 
> Arnaud
> 
> 
> 
>>Frantisek
>>
>>Brad Midgley wrote:
>>
>>>Frantisek
>>>I noticed this too, but we know it can go lower... the backlight goes
>>>just a bit lower when you're idle and before it turns off altogether.
>>>Brad
>>>
>>
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> 
>