[solved] pcie storage device removal makes Xorg pick wrong GPU

LaptopDev · 2026-01-23 22:59:30

Generally speaking, I am working on getting my NVIDIA 3090FE to work as a secondary gpu (not a display gpu) alongside my primary gpu which is my AMD RX 580.

It might be pertinent -- I am using a pcie to m.2 adapter for this 'removable' media drive that seems to be causing problems. I thought disabling CSM in bios would help but this is still not working at selecting my AMD gpu as my default:

/etc/X11/xorg.conf.d/10-amd.conf
https://0x0.st/PPhg.conf

/etc/X11/xinit/xinitrc
https://0x0.st/8YCS.sh

/etc/X11/xinit/xserverrc
https://0x0.st/PPdz.sh

/usr/bin/startx
https://0x0.st/PPPm.sh

journal-log
https://0x0.st/PPhI.txt

I remove the 'media' storage device from my system when the system is off, and then I reboot into my system. With the media storage device removed I cannot launch Xorg with startx. If you look at my /etc/fstab and /etc/crypttab below, I have the storage drives failsafe handle non-attachment via systemd/fstab/crypttab.

/etc/fstab
https://0x0.st/PPhk.txt

crypttab_copy
https://0x0.st/PPF-.txt

Last edited by LaptopDev (2026-01-30 01:00:20)

Scimmia · 2026-01-23 23:10:41

    BusID "PCI:12:0:0"

Is that BusID changing?

seth · 2026-01-24 09:30:11

Jan 23 16:35:46 rog kernel: amdgpu 0000:0b:00.0: vgaarb: deactivate vga console

but there's also no nvidia GPU in that journal?

Xorg will pick whatever GPU gets explicitly referenced first, just having a config that has

Section "Device"
    Identifier "AMD"
    Driver "amdgpu"
EndSection

an no equivalent entry for nvidia should™ prefer the amd GPU.
Otherwise you can just have a static screen

Section "Screen"
    Identifier "AMD"
    Device "AMD"
EndSection

Section "Device"
    Identifier "AMD"
    Driver "amdgpu"
EndSection

LaptopDev · 2026-01-29 07:10:53

Is that BusID changing?

I think so

Section "Screen"
    Identifier "AMD"
    Device "AMD"
EndSection

Section "Device"
    Identifier "AMD"
    Driver "amdgpu"
EndSection

I removed my storage drives and added my 3090FE and restarted my pc and ran startx with that device+screen configuration. I didn't save my original xorg.0.log before I removed my storage drives when X was working. So no storage devices+amd+nvidia failed to start X, and I got the following output in xorg.0.log:

https://0x0.st/PNGY.txt | journal-log_without-storage-with-nvidia-gpu

I thought, oh good, now I can show you the error. So I went about removing my nvidia gpu without re-installing my storage devices. But I rebooted and ran startx and got an error. I had believed i already tested booting without my storage devices successfully through modifying crtypttab and fstab configuration files. So here is that log of no storage devices+amd (nvidia removed):

https://0x0.st/PNkh.txt | journal-log_without-storage-and-without-nvidia-gpu

So I hadn't actually carefully reviewed either of the above logs at this point. I reinserted the storage drives where they were when inserted and booted into X with startx fine. Here is my current log of that:

https://0x0.st/PNkF.txt | journal-log_with-storage-without-nvidia-gpu

I wanted startx to run cleanly without attached storage before debugging AMD+NVIDIA, but that issue apparently remains unresolved. My guess is startx failed after adding/removing the NVIDIA card because the PCI enumeration changed and Linux no longer matched the devices.

So I have two nvme storage drives. One is connected without any adapter, the other is connected on a pcie slot with an adapter. I wanted to see what happens when I try startx with amd gpu only and different storage devices attached. I got some logs of each case below as well:

xorglog_nopcitonvme_adapter https://0x0.st/PNdl.txt (doesn't launch X)

xorglog_nvme_removed https://0x0.st/PNdU.txt (doesn't launch X)

xorglog_storage_drives_both_back_in https://0x0.st/PNd0.txt

I shared those few logs with chatgpt where no NVIDIA gpu was physically installed and it suggested that even with pcie enumeration changing, the drm node shifts and xorg launches the wrong drm node causing the problem without nvidia gpu presence influencing the failure. Chatgpt thinks PCIe storage removal → PCIe re-enumeration → DRM node index shifts → Xorg tries the wrong DRM node → startx fails.

Last edited by LaptopDev (2026-01-29 07:26:40)

seth · 2026-01-29 10:13:06

[   119.338] (EE) open /dev/dri/card0: No such file or directory
[   119.338] (WW) Falling back to old probe method for modesetting
[   119.338] (EE) open /dev/dri/card0: No such file or directory
[   119.338] (EE) No devices detected.

[    46.404] (==) ServerLayout "Layout0"
[    46.404] (**) |-->Screen "Screen0" (0)
[    46.404] (**) |   |-->Monitor "Monitor0"
[    46.404] (**) |   |-->Device "GPU0"
[    46.404] (**) |   |-->GPUDevice "AMD"

grep -r . /{etc,usr/share}/X11/xorg.conf*

LaptopDev · 2026-01-29 16:49:33

seth wrote:

grep -r . /{etc,usr/share}/X11/xorg.conf*

grep-cmd_stdo
https://0x0.st/Pqs3.txt

After removing /etc/X11/xorg.conf.d/xorg-fvwm.conf My amd gpu is picked when my 3090FE is installed, without my storage devices installed. I don't suppose the storage devices presences should interfere.

Last edited by LaptopDev (2026-01-29 17:40:46)

seth · 2026-01-29 19:43:17

Please post the xorg log for that scenario.

LaptopDev · 2026-01-30 00:59:43

seth wrote:

Please post the xorg log for that scenario.

Uh I have rebooted a few times since then; I also upgraded my system nvme to 4tb from 2tb and moved the compute directories from the external pcie adapter'd drive to my system nvme so no longer am using the pcie to nvme adapter.

Edit: marked this thread as solved

Last edited by LaptopDev (2026-01-30 01:00:42)

Arch Linux

#1 2026-01-23 22:59:30

[solved] pcie storage device removal makes Xorg pick wrong GPU

#2 2026-01-23 23:10:41

Re: [solved] pcie storage device removal makes Xorg pick wrong GPU

#3 2026-01-24 09:30:11

Re: [solved] pcie storage device removal makes Xorg pick wrong GPU

#4 2026-01-29 07:10:53

Re: [solved] pcie storage device removal makes Xorg pick wrong GPU

#5 2026-01-29 10:13:06

Re: [solved] pcie storage device removal makes Xorg pick wrong GPU

#6 2026-01-29 16:49:33

Re: [solved] pcie storage device removal makes Xorg pick wrong GPU

#7 2026-01-29 19:43:17

Re: [solved] pcie storage device removal makes Xorg pick wrong GPU

#8 2026-01-30 00:59:43

Re: [solved] pcie storage device removal makes Xorg pick wrong GPU

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