AMD Radeon RX 640 not recognized on freshly installed Ubuntu 20.04
Solution 1:
Kernel Mode Setting (KMS) is a method for setting display resolution and depth in the kernel space rather than user space. The Linux kernel's implementation of KMS enables native resolution in the framebuffer and allows for instant console (tty) switching. KMS also enables newer technologies (such as DRI2) which will help reduce artifacts and increase 3D performance, even kernel space power-saving. With Kernel Mode Setting (KMS), the kernel is now able to set the mode of the video card. This makes fancy graphics during bootup, virtual console and X fast switching possible, among other things (see also this).
I am posting actions that may get you going.
Selective modeset
Selectively disable Kernel Mode Setting for one or the other graphics card by adding to the grub boot line (either temporary or permanent, you already know how to do both)
amdgpu.modeset=0
radeon.modeset=0
i915.modeset=0
for Radeon, Radeon (legacy driver), or Intel, respectively. The link also provides other alternatives to try.
Combine this with inxi -G as you did, and with lspci -k | grep -EA4 'VGA|3D'.
Reinstall
You may need to access recovery mode and reinstall drivers as shown here. Perhaps you can access a terminal (e.g. as in here) and do the same.
Related
- https://www.notebookcheck.net/Radeon-RX-640-vs-Radeon-620-vs-Radeon-610_9935_9927_9933.247598.0.html
- https://forums.linuxmint.com/viewtopic.php?t=122257
- https://www.udoo.org/docs-bolt/Operating_Systems/Linux/Known_issues.html
- https://itsfoss.com/fix-ubuntu-freezing/