CODEWITHSUNDEEP
copencl
galois
galois

Reputation: 857

Why isn't OpenCL finding any devices?

I've been messing around with OpenCL, and it seems it's not detecting that I have a device to use in my computer (which I do).

Here's the result of dxdiag:

enter image description here

Here is the first part of my code, where the error is being raised, checking for the number of devices available on my machine.

cl_platform_id platform;
cl_uint num_devices;
cl_int err;

//get first platform
err = clGetPlatformIDs(1, &platform, NULL);

if (err < 0){
    perror("Couldn't find any platforms");
    exit(1);
}

//determine number of devices: ERROR RAISED AS RESULT OF THIS
err = clGetDeviceIDs(platform, CL_DEVICE_TYPE_ALL, 1, NULL, &num_devices);

if (err < 0){
    perror("Couldn't find any devices");
    exit(1);
}

This is the output from this code: enter image description here

And when I print the number of devices it is finding, with

printf("Found %d devices", num_devices);

It gives the same number every time:

enter image description here

Please let me know what other information may help in figuring this out.

Upvotes: 0

Views: 2367

Answers (2)

agnu17
agnu17

Reputation: 398

make sure that both 32bit and 64bit opencl drivers are installed. If your app is 64 bit, but only a 32bit driver is installed, the device will not be found.

you can check installed devices using my app: https://github.com/zbendefy/opencl-z/blob/master/opencl_z_1_1b.jar

Upvotes: 1

Mr. Llama
Mr. Llama

Reputation: 20889

You can't be certain that it's not finding the devices because you haven't properly checked the return value. There are 5 values (more, depending on your OpenCL version) that clGetDeviceIDs can return:

  • CL_SUCCESS if the function is executed successfully.
  • CL_INVALID_PLATFORM if platform is not a valid platform.
  • CL_INVALID_DEVICE_TYPE if device_type is not a valid value.
  • CL_INVALID_VALUE if num_entries is equal to zero and device_type is not NULL or if both num_devices and device_type are NULL.
  • CL_DEVICE_NOT_FOUND if no OpenCL devices that matched device_type were found.

You should check your err value against those to be sure that CL_DEVICE_NOT_FOUND is actually the case.

Similarly, you should use supply the num_platforms value for clGetPlatformIDs. It's possible that the platform you've selected doesn't have valid devices, but another platform does.

Upvotes: 1

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