UMDF Driver for Ambient Light Sensor RRS feed

  • Question

  • I want to develop and UMDF driver for an ambient light sensor device that exposes a I2C (SMBus) interface. I understand that the SMBus interface is only exposed to kernel mode drivers. How do I access this interface from a UMDF driver ?

    Thanks in advance.
    Wednesday, June 10, 2009 1:47 AM


  • Hello- The suggested implementation here is to write the proper ACPI BIOS code to expose your light sensor in such a way that it is compliant with the ACPI 3.0b, please see the following whitepaper on this topic:
    Integrating Ambient Light Sensors with Windows 7 Computers [174 KB]

    When your ALS is properly exposed via the ACPI methods (_ALI, _ALR, etc)- the in-box Windows 7 drivers and Adaptive Brightness feature will be utilized.

    Please let me know if this answers your question, and if there are any reasons that you would want to write your own UMDF driver.
    Monday, June 15, 2009 5:06 PM