Linux systems struggle with dual GPUs and dual monitors; seek assistance
Linux systems struggle with dual GPUs and dual monitors; seek assistance
Hello, I'm dealing with an unusual problem on my main system. It appears to fail any Linux installation I attempt. There might be a special boot or kernel setting that could resolve this, but???? My hardware details: hardware IDs 0x1002:0x687f:1:5:Vega 10 XL/XT [Radeon RX Vega 56/64] and 0x1002:0x67e3:1:5:Baffin Polaris11 [Radeon Pro WX 4100]. I'm using an ASUS X570-p motherboard with a 3900X Direct CPU x16 slot, featuring the Vega 56 — DP Primary monitor AOC 1440p ultrawide.
My experience shows that the built-in amdgpu driver isn't recognizing both cards properly. It seems the system thinks it's only getting one card, possibly because of PCI-E index mismatches or incorrect indexing. The primary display is a 1440p ultrawide, but it's connected to an unidentified adapter, which affects rendering quality.
I've tried Ubuntu or Pop-OS (21.04), but only got low-resolution LVMW 1024x768 output. No documentation suggests forcing dual cards, and in Manjaro-GNOME the live ISO stalls at the graphical interface checkpoint. On Manjaro-KDE it hangs there too. I can't swap the cards or remove the wx4100 without it failing again.
My training issues are minor — just a few troubleshooting steps that don’t seem to stick. Any suggestions would be greatly appreciated.
This explanation relies on various system details that aren’t clear from what you shared. To get a solid understanding, you should run `lspci` and check the Xorg.0.log file, plus look at the Kernel log from a boot using `journalctl -kb`. Also, examine `ls -l /dev/dri` to see which GPUs the kernel recognizes. Based on what I infer, X.org likely doesn’t support many graphics cards by default, possibly intentionally, since a GPU could serve multiple purposes—like computing or separate sessions—and the system might prefer one unless specified otherwise. Most desktop GUI settings don’t heavily influence X.org configuration, except for the outputs from active GPU sessions. You’ll probably find relevant guidance in X.org documentation, though it’s not always easy to locate. Arch Wiki has some tips for managing multiple GPUs, but you should verify your distribution’s examples. Overall, it’s wise to start with those commands before making assumptions.
Consider setting up with a single GPU initially, then add the second one later. Alternatively, detach the cable from one of the GPUs that didn’t cause problems with your RX 6900XT and GTX 1060 combo—based on what I recall, but you likely hadn’t connected anything to the GTX 1060 at that time.
Can't relate to X problems because on Manjaro with an AMD GPU the system will automatically switch to Wayland for both Gnome and KDE. For certainty, check the kernel logs after boot using dmesg --human --kernel --reltime. Review the output carefully—look for any AMDGPU module entries. You might also try sudo journalctl -k -b0 for the current boot session, though interpreting it can be challenging as it displays raw text. Please share the logs here if you'd like help analyzing them.
Hello, thank you for your feedback. The problem occurred some time ago, and I had previously abandoned the installation on that Linux system for the X570, which is supported with the latest Windows 11. Most of my activities are done using that OS. I was wondering since Pop! OS with NVIDIA fully supports my Frankensteined machine (I installed a Quadro M2000M). The Dell M4700 requires some infodrivers to run Windows 10, which is a bit challenging. I wanted to continue working after the Windows EOL. Two workstations came up: one with an ASRock Dual e5-2670v1 (R9-390) running Mint LTS after turning off AMD GPU in GRUB, and another HP Z420 with EVGA-1070 that might be next on the Linux path. However, I randomly downloaded an Ubuntu 20.04 LTS, reformatted it to USB, and it started working smoothly on the Asus X570 when I freed up space on a spare NVMe drive. It would just launch without any issues. How did I drag the window around on both screens?