USB Monitor Class Driver

[ashok]

Hi,

I am new to Windows Driver Development. I have a problem in modifying
the Brightness of USB monitor device which is provided by the Hardware
vendor. Here is my problem statement.

I have a USB monitor, the brightness has to be controlled from an
windows application. The Hardware Vendor has not provided any driver
other than the Microsoft provided HID component. We came to know from
DDK that we can change the brightness using HID interfaces such as
HID_GetReport etc. but the documentation is not clear about the
parameters. Please let me know any pointers related to this.

Also the Monitor Report descriptors from the Hardware vendor is as
shown below. Please let me know if these interfaces are sufficient to
modify the birghtness level from the Application.

Field Value Meaning
------- ------------
---------------------
Usage Page 0x05 0x80 USB Monitor
Usage 0x09 0x01 Monitor Control
Collection 0xA1 0x01 Start definition of
application collection
Usage Page 0x05 0x82 VESA Virtual Controls
Usage 0x09 0x10 Brightness
Logical Minimum 0x15 0x00 Minimum brightness (0 = backlight
off)
Logical Maximum 0x25 0x64 Maximum brightness
Report Count 0x95 0x01 One count
Report Size 0x75 0x08 8 bits per count
Input 0x81 0x02 Input is Data, Variable,
Absolute
End Collection 0xC0 End collection definition
Collection 0xA1 0x01 Start definition of
application collection
Usage Page 0x05 0x82 VESA Virtual Controls
Usage 0x09 0x10 Brightness
Logical Minimum 0x15 0x00 Minimum brightness (0 = backlight
off)
Logical Maximum 0x25 0x64 Maximum brightness
Report Count 0x95 0x01 One count
Report Size 0x75 0x08 8 bits per count
Output 0x01 0x02 Output is Data, Variable, and
Absolute
End Collection 0xC0 End collection definition

 

[Doron Holan [MSFT]]

download the wdk and look at the various HID samples which show how to use
the HID parser (hid.dll) in user mode

d