Suggested fix for "AMDGPU Pro 17.40 with AMD RX Vega doesn't work" altough OpenCL is working (says gfx900 unsupported device)
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Description

System Information
Operating system and graphics card
Ubuntu 17.04
RX Vega 64
AMDGPU Pro 17.40

Short description of error
as said cycles doens't find any compatible opencl device..
running with cycles debug command line argument reports "unsupported device gfx900"..
searching through Blender code I see the root cause:

it's in "blender/intern/cycles/device/opencl/opencl_util.cpp" file:

if(platform_name == "AMD Accelerated Parallel Processing" &&
	   device_type == CL_DEVICE_TYPE_GPU)
	{
		if(driver_major < 2236) {
			VLOG(1) << "AMD driver version " << driver_major << "." << driver_minor << " not supported.";
return false;

as AMDGPU Pro Vega OpenCL reports driver version string "1.1 (HSA,HSAIL)" and blender searches for driver version >=2236.. this number is only used in platform driver that for Vega 17.40 driver reports 2482.4 and Windows reports:
Driver version: 2482.5 (PAL,HSAIL)
so it goes well

Details

Type
Bug