Включить OpenCL в Ubuntu 20.04 для Darktable на Thinkpad T495 (AMD iGPU)

У меня Thinkpad T495 с AMD 3500 PRO:

$ lspci | grep VGA
06:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Picasso (rev d2)

Используя команду Clinfo, я вижу, что платформа имеет профиль OpenCL:

$ clinfo
Number of platforms                               1
  Platform Name                                   AMD Accelerated Parallel Processing
  Platform Vendor                                 Advanced Micro Devices, Inc.
  Platform Version                                OpenCL 2.0 AMD-APP (3182.0)
  Platform Profile                                FULL_PROFILE
  Platform Extensions                             cl_khr_icd cl_amd_event_callback 
  Platform Extensions function suffix             AMD

  Platform Name                                   AMD Accelerated Parallel Processing
Number of devices                                 0

NULL platform behavior
  clGetPlatformInfo(NULL, CL_PLATFORM_NAME, ...)  No platform
  clGetDeviceIDs(NULL, CL_DEVICE_TYPE_ALL, ...)   No platform
  clCreateContext(NULL, ...) [default]            No platform
  clCreateContext(NULL, ...) [other]              No platform
  clCreateContextFromType(NULL, CL_DEVICE_TYPE_DEFAULT)  No devices found in platform
  clCreateContextFromType(NULL, CL_DEVICE_TYPE_CPU)  No devices found in platform
  clCreateContextFromType(NULL, CL_DEVICE_TYPE_GPU)  No devices found in platform
  clCreateContextFromType(NULL, CL_DEVICE_TYPE_ACCELERATOR)  No devices found in platform
  clCreateContextFromType(NULL, CL_DEVICE_TYPE_CUSTOM)  No devices found in platform
  clCreateContextFromType(NULL, CL_DEVICE_TYPE_ALL)  No devices found in platform

Я попытался установить amdgpu-pro, но установка завершилась неудачно с этой ошибкой

Unpacking amdgpu-dkms-firmware (1:5.6.0.15-1098277) ...
dpkg: error processing archive /var/opt/amdgpu-pro-local/./amdgpu-dkms-firmware_5.6.0.15-1098277_all.deb (--unpack):
 trying to overwrite '/usr/share/doc/amdgpu-dkms-firmware/LICENSE', which is also in package rock-dkms-firmware 1:3.7-20
dpkg-deb: error: paste subprocess was killed by signal (Broken pipe)
Errors were encountered while processing:
 /var/opt/amdgpu-pro-local/./amdgpu-dkms-firmware_5.6.0.15-1098277_all.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)

По-прежнему, когда я открываю Darktable, опция OpenCL не поддерживается: