lspci -nnk
01:00.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc. [AMD/ATI] RV370 [Radeon X300] [1002:5b60]
Subsystem: PC Partner Limited / Sapphire Technology Radeon X300 (PCIE) [174b:0500]
sudo lspci -vnnk
01:00.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc. [AMD/ATI] RV370 [Radeon X300] [1002:5b60] (prog-if 00 [VGA controller])
Subsystem: PC Partner Limited / Sapphire Technology Radeon X300 (PCIE) [174b:0500]
Flags: bus master, fast devsel, latency 0, IRQ 5
Memory at e8000000 (32-bit, prefetchable) [size=128M]
I/O ports at de00 [size=256]
Memory at fddf0000 (32-bit, non-prefetchable) [size=64K]
Expansion ROM at fddc0000 [disabled] [size=128K]
Capabilities: [50] Power Management version 2
Capabilities: [58] Express Endpoint, MSI 00
Capabilities: [80] MSI: Enable- Count=1/1 Maskable- 64bit+
Capabilities: [100] Advanced Error Reporting
EDIT: This card works in PureOS 9 with kernel 4.19.0-13 and radeon driver !
I have KDE Plasma running with it, using DVI output...
UPDATE 2023/08/18: This card works natively now in Trisquel 11 with kernel 6.4.10-gnu