On Sun, 10 Oct 2010 08:29:52 +0700, Mulyadi Santosa <[email protected]> 
wrote:
> On Sat, Oct 9, 2010 at 14:46, Ali Polatel <[email protected]> wrote:
> > Hi everyone,
> >
> > I want to write laptop extras for my laptop¹ so that changing brightness
> > of the screen etc. are supported by Linux.
> 
> I am just thinking, how about starting with how xbacklight works and
> see its source code? :)

Well xbacklight doesn't work at all on this box:
$> xbacklight
No outputs have backlight property

Let me give a bit more detail about the ACPI properties:
$> tree --charset=ascii /proc/acpi/video
/proc/acpi/video
`-- VGA1
    |-- CRT
    |   |-- brightness
    |   |-- EDID
    |   |-- info
    |   `-- state
    |-- DOS
    |-- HDMI
    |   |-- brightness
    |   |-- EDID
    |   |-- info
    |   `-- state
    |-- info
    |-- LCD
    |   |-- brightness
    |   |-- EDID
    |   |-- info
    |   `-- state
    |-- POST
    |-- POST_info
    `-- ROM

4 directories, 17 files
$> cat /proc/acpi/video/VGA1/*/brightness
<not supported>
<not supported>
<not supported>
$> cat /proc/acpi/video/VGA1/*/info
device_id:    0x0100
type:         CRT
known by bios: no
device_id:    0x0121
type:         UNKNOWN
known by bios: no
device_id:    0x0110
type:         LCD
known by bios: no

As you can see, the brightness property of VGA1 is not supported.

> -- 
> regards,
> 
> Mulyadi Santosa
> Freelance Linux trainer and consultant
> 
> blog: the-hydra.blogspot.com
> training: mulyaditraining.blogspot.com
> 

-- 
Regards,
Ali Polatel

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