Calling NvAPI_GPU_SetEDID on Nvidia card

Question

How do you call this method on Nvidia GPU:

NVAPI_INTERFACE NvAPI_GPU_SetEDID (
    NvPhysicalGpuHandle hPhysicalGpu,
    NvU32   displayOutputId,
    NV_EDID *   pEDID 
)

Src: http://docs.nvidia.com/gameworks/content/gameworkslibrary/coresdk/nvapi/group__gpu.html#ga6a41b31dd9743120213435d985f8fbcf

I need to execute the above command to remove all EDID set on all DisplayOutputs on our new Quadro Graphics Cards. Based on the API documentation, I tried searching for NvPhysicalGpuHandle and came across this project/library:

https://github.com/openhardwaremonitor/openhardwaremonitor/blob/master/Hardware/Nvidia/NVAPI.cs

This does not have the method I need NvAPI_GPU_SetEDID

I am not hardware programmer, I just need to be able to call this one command. any ideas? Can this be achieved using nvapi.dll/nvapi64.dll via pinvoke or something?

Answer 1

I personally didn't test this, but you can try the library and see if it can set EDID information without any problem, if it fails, please open an issue.

https://github.com/falahati/NvAPIWrapper

---

Here is how you should do it,

1. First, you need to find the right DisplayDevice or GPUOutput that you want to write EDID information to. There are multiple ways to do so.
   • Get a list of all PhysicalGPUs in the system using the NvAPIWrapper.GPU.PhysicalGPU.GetPhysicalGPUs() static method, then select the PhysicalGPU you desire based on your logic. After finding the right PhysicalGPU, use the NvAPIWrapper.GPU.PhysicalGPU.GetDisplayDevices() method to get a list of all connected DisplayDevices to that GPU and store the right one in a variable.
   • Instead of searching for connected DisplayDevices, you can also go for the GPUOutputs. Just like before, you first need to find the right PhysicalGPU and then you can get a list of all GPUOutputs using the NvAPIWrapper.GPU.PhysicalGPU.ActiveOutputs property and store the right GPUOutput in a variable.
   • Another way to find the right DisplayDevice is to go for a list of all Displays. To do so, you need to use the NvAPIWrapper.Display.Display.GetDisplays() static method. This returns an array of Displays. Then using the NvAPIWrapper.Display.Display.DisplayDevice property, you can get the corresponding DisplayDevice of a Display.
2. After finding the right DisplayDevice or GPUOutput, you should use the NvAPIWrapper.GPU.PhysicalGPU.WriteEDIDData() method. This method allows you to write EDID data stored in a byte array to the DisplayDevice or the GPUOutput you selected before.

Note: Make sure to capture NVIDIAApiException and check for the NVIDIAApiException.Status property in case something went wrong.