ambient light sensor for dell latitude

[Mario Limonciello]

Hi Nicolò:

I'm sorry, I'm not familiar with the document.  It's written by BIOS
documentation teams who worked to implement the underlying
specifications.  You will probably need to do some experimentation to
see what data is encapsulated in the different returns.  When you do
sort it out, I would recommend adding it as comments to your source code
so others who read it will have a better understanding.

Regards

Nicolò Chieffo wrote:
> Mario, can you help me to understand what the SMI codes do?
> This is the information I have:
>
>  SMI Interface:
>
>     cbClass:  17
>     cbSelect: 10
>     Name:     Ambient Light Sensor Status and Control
>
>     On entry:
>     cbARG1, byte 0: Function to perform:
>         0   Get ALS Status
>         1   Control ALS
>         2   Get Brightness Table
>
>     If cbARG1, byte 0 is 1 (Control ALS):
>     cbARG2, byte 0: Command
>         0   Disable ALS
>         1   Enable ALS
>     cbARG2, byte 1: ALS low limit to set
>     cbARG2, byte 2: ALS high limit to set
>
>     On return:
>     cbRES1: Return code
>         0   Completed successfully
>         -1  Completed with error
>         -2  Function not supported
>
>     If cbARG1 byte 0 was 0 (Get ALS Status):
>     cbRES2, byte 0: Current ALS Status
>         0   Disabled
>         1   Enabled
>     cbRES3, byte 0: Current ALS low limit
>     cbRES3, byte 1: Current ALS high limit
>     cbRES3, byte 2: Absolute ALS low limit
>     cbRES3, byte 3: Absolute ALS high limit
>
>     If cbARG1 byte 0 was 2 (Get Brightness Table):
>     cbRES2: Bytes 3..0 of the brightness table
>     cbRES3: Bytes 7..4 of the brightness table
>
>
> Here are my questions:
> 1) what is the ALS high and low 'limit'?
> 2) what is the brightness table?
> 3) is there a way to get the current brightness level when the ALS is enabled?
>   

-- 
Mario Limonciello
*Dell | Linux Engineering*
mario_limonciello at dell.com
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