> 7790 - это BONAIRE, т. е. GCN 1.1. Оно работает с драйвером
> AMDGPU, если включить одну опцию при сборке ядра.

а можно подробнее что за опция ?

зы: нашёл
http://www.phoronix.com/scan.php?page=news_item&px=Linux-4.5...
Additionally, this kernel build I uploaded today also enables CONFIG_DRM_AMDGPU_CIK. This option enables the AMDGPU DRM driver to work for Sea Islands GPUs. This was the unofficial option for pre-Tonga hardware where AMD had initially developed this driver but then disabled the support since the CIK GPUs are already supported by Radeon DRM. However, given the new Catalyst driver and forthcoming Vulkan driver being tied to the AMDGPU driver, enabling AMDGPU support for older GCN GPUs is one of the options being looked at by AMD. So if you want to test it, go ahead and try this kernel.