@x_wings:

If both cards are present, same errors at boot plus a bunch of RIP
RDX
RBX
RCX
RSI
RD1...

errors and screen freezes w/o any option available

@tuxintuxedo

will try that in a minute.

@The_Aquabat @tuxintuxedo

Bingo! The iommu=pt did the trick.

egoi@MSI-B450:~$ DRI_PRIME=1 glxinfo | grep OpenGL
OpenGL vendor string: X.Org
OpenGL renderer string: Radeon RX 570 Series (POLARIS10, DRM 3.35.0, 5.4.0-29-generic, LLVM 9.0.1)
OpenGL core profile version string: 4.6 (Core Profile) Mesa 20.0.4
OpenGL core profile shading language version string: 4.60
OpenGL core profile context flags: (none)
OpenGL core profile profile mask: core profile
OpenGL core profile extensions:
OpenGL version string: 4.6 (Compatibility Profile) Mesa 20.0.4
OpenGL shading language version string: 4.60
OpenGL context flags: (none)
OpenGL profile mask: compatibility profile
OpenGL extensions:
OpenGL ES profile version string: OpenGL ES 3.2 Mesa 20.0.4
OpenGL ES profile shading language version string: OpenGL ES GLSL ES 3.20
OpenGL ES profile extensions:
egoi@MSI-B450:~$ DRI_PRIME=0 glxinfo | grep OpenGL
OpenGL vendor string: X.Org
OpenGL renderer string: Radeon RX 570 Series (POLARIS10, DRM 3.35.0, 5.4.0-29-generic, LLVM 9.0.1)
OpenGL core profile version string: 4.6 (Core Profile) Mesa 20.0.4
OpenGL core profile shading language version string: 4.60
OpenGL core profile context flags: (none)
OpenGL core profile profile mask: core profile
OpenGL core profile extensions:
OpenGL version string: 4.6 (Compatibility Profile) Mesa 20.0.4
OpenGL shading language version string: 4.60
OpenGL context flags: (none)
OpenGL profile mask: compatibility profile
OpenGL extensions:
OpenGL ES profile version string: OpenGL ES 3.2 Mesa 20.0.4
OpenGL ES profile shading language version string: OpenGL ES GLSL ES 3.20
OpenGL ES profile extensions:
egoi@MSI-B450:~$



Should I write this option into my grub launch file?

What am i doing with this?

The +nomodeset does not seem to be necessary (I tired with and w/o and both times it was just fine!) What do I do with the +nomodeset?

My kid is happy as hell. He says thanks you all.

To make things permanent, you have to add the iommu=pt to the /etc/default/grub file.
Look for the line
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
and make it
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash iommu=pt"
Save the file and run: sudo update-grub
The above used method DRI_PRIME=1 programtorun is universal. You can run any kind of program on the dedicated GPU if needed.
I also recommend using the Kisak PPA link for better performance, although their support is preliminary for 20.04 so you should wait for it to become more mature.
As far as I can tell, the pt switch is for passthrough regarding virtualization. I think currently this is more like a bug with problematic behavior that is corrected with this. Shouldn't really affect other things.
Congrats to you and The_Aquabat. :D

Last edited by tuxintuxedo on 12 May 2020 at 5:04 pm UTC

@tuxintuxedo

I made the changes permanent and the system is stable now. Will hook onto the Kisak PPA when I update to 20.04.

Many thanks for your patience and support.

This is really good to know. I don't have an AMD card at the moment, but I plan on buying one in the future. I'm sure this will save people a lot of trouble.