# dpkg -s xserver-xorg-video-amdgpu
...
Description: X.Org X server -- AMDGPU display driver
 This package provides the 'amdgpu' driver for the AMD Radeon cards. The
 following chip families should be supported: Bonaire, Hawaii, Kaveri, Kabini
 Mullins, Iceland, Tonga, Carrizo, Fiji, Stoney.


this list is essentially GCN-2 and later. and yet:


# lspci
...
01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI]
Tahiti PRO [Radeon HD 7950/8950 OEM / R9 280]


it turns out that the AMDGPU driver has been working for all GCN hardware,
for years already. perhaps the package description should be updated to
reflect this fact; the current version is rather misleading.


https://dri.freedesktop.org/docs/drm/gpu/amdgpu.html

https://www.phoronix.com/scan.php?page=news_item&px=AMDGPU-GCN-1.0-Analog-Block

https://en.wikipedia.org/wiki/Graphics_Core_Next#Generations