Arch Linux

talowicz

Member

Registered: 2024-08-13

Posts: 7

[SOLVED] XRandR throwing 'xrandr: Configure crtc 6 failed'

Hello all!

I am running into an issue configuring my KDE + SDDM desktop to use one of the two Radeon GPUs in my system. I intend to
passthrough the unused one to virtual machines.

I would like DisplayPort-0 to be off, while the two other displays (HDMI-A-1-1 and DisplayPort-1-3) be used by the host.

DisplayPort-0 belongs to GPU1 in x16 slot. <---- currently in use, hence why I am posting this
HDMI-A-1-1 and DisplayPort-1-3 to GPU2 in x8 slot.

After each mode setting attempt, the screen (DisplayPort-0) goes black - as expected, then xrandr prints the error.

-----------------------------------------------------------

Initial output of running xrandr: http://0x0.st/XUx7.txt
Running xrandr with --newmode:    http://0x0.st/XU3s.txt
Running xrandr with --addmode:    http://0x0.st/XU3z.txt
Final output of running xrandr:   http://0x0.st/XU3i.txt
Setting monitor mode with xrandr: http://0x0.st/XU3o.txt

-----------------------------------------------------------

$ tail -100 /var/log/Xorg.0.log
   http://0x0.st/XU3N.txt

$ tail -100 ~/journalctl_-b_output.txt
   http://0x0.st/XU3b.txt

-----------------------------------------------------------

Please tell me if I should post any more log files. Thanks in advance!

Last edited by talowicz (2024-10-29 16:51:14)

seth

Member

Registered: 2012-09-03

Posts: 60,779

Re: [SOLVED] XRandR throwing 'xrandr: Configure crtc 6 failed'

After each mode setting attempt, the screen (DisplayPort-0) goes black - as expected, then xrandr prints the error.

Why is it enabled itfp?

tail -100 /var/log/Xorg.0.log

Please post the entire file, not just some tail

I intend to passthrough the unused one to virtual machines.

"Intend to" or "assume to be currently"?

---

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talowicz

Member

Registered: 2024-08-13

Posts: 7

Re: [SOLVED] XRandR throwing 'xrandr: Configure crtc 6 failed'

After each mode setting attempt, the screen (DisplayPort-0) goes black - as expected, then xrandr prints the error.

Why is it enabled itfp?

tail -100 /var/log/Xorg.0.log

Please post the entire file, not just some tail

I intend to passthrough the unused one to virtual machines.

"Intend to" or "assume to be currently"?

------------------------------------------------------------------------------------------------------------------------------

Why is it enabled itfp?

It is the only output which is working as of right now. Even changing initial display output to PCIE slot 2 in my UEFI
settings does not yield positive results and ends of showing no display at all. I also did some further digging into the
journalctl file and found these lines: http://0x0.st/XUlo.txt. PCI-00:0e:00.0 is the home of DisplayPort-0, and
PCI-00:11:00.0 is the home of the two other specified. Do these lines mean I need to change the boot VGA device? Would I do this by putting some kernel parameters in my grub config?

Please post the entire file, not just some tail

Apologies... http://0x0.st/XUlS.txt

"Intend to" or "assume to be currently"

Sorry, I was not specific. I use a libvirt hook to detach the GPU from the amdgpu driver and attach it to vfio-pci. This works
fine and the VM outputs display moments later after booting. I just dont have any video out for the host.

Another problem does arise when I shutdown the VM; The GPU does not reattach to the amgdpu driver. This has to be a problem
with the hook that should be simple to fix, but lets do one thing at a time ay!

seth

Member

Registered: 2012-09-03

Posts: 60,779

Re: [SOLVED] XRandR throwing 'xrandr: Configure crtc 6 failed'

The server is running on "PCI:*(17@0:0:0) 1002:743f", the RX 6500 XT
The RX 6950 XT is available via (reverse) prime

There's no DisplayPort-0, there're the (disfuncional, see below) direct outputs on DisplayPort-3 and HDMI-A-1 and the reverse prime output on DisplayPort-1-0
The server crashes

[   218.198] (EE) Screen(s) found, but none have a usable configuration.
[   218.198] (EE) 
Fatal server error:
[   218.198] (EE) no screens found(EE) 
[   218.198] (EE) 

for

[   218.171] (WW) AMDGPU(0): Unable to find initial modes
[   218.171] (EE) AMDGPU(0): Output DisplayPort-3 enabled but has no modes
[   218.171] (EE) AMDGPU(0): Output HDMI-A-1 enabled but has no modes

because

[   218.152] (II) AMDGPU(0): No remaining probed modes for output DisplayPort-3
[   218.171] (II) AMDGPU(0): No remaining probed modes for output HDMI-A-1

=> Remove xf86-video-amdgpu, if that doesn't help, block the simpledrm device, if that also doesn't work post a complete system journal.
Add "initcall_blacklist=simpledrm_platform_driver_init" to the https://wiki.archlinux.org/title/Kernel_parameters

sudo journalctl -b | curl -F 'file=@-' 0x0.st

It's not supposed to contain any sensitive data (though sometimes routeable IPv6 addresses are listed and all sudo calls get audited w/ their parameters) and ftr, the disk UUIDs are for collision prevention, they're unique but don't reveal anything else.

---

How to upload text · How to boot w/o GUI · Disable Windows Fast-Start! · Fix your xinitrc

talowicz

Member

Registered: 2024-08-13

Posts: 7

Re: [SOLVED] XRandR throwing 'xrandr: Configure crtc 6 failed'

The server is running on "PCI:*(17@0:0:0) 1002:743f", the RX 6500 XT
The RX 6950 XT is available via (reverse) prime

There's no DisplayPort-0, there're the (disfuncional, see below) direct outputs on DisplayPort-3 and HDMI-A-1 and the reverse prime output on DisplayPort-1-0
The server crashes

[   218.198] (EE) Screen(s) found, but none have a usable configuration.
[   218.198] (EE) 
Fatal server error:
[   218.198] (EE) no screens found(EE) 
[   218.198] (EE) 

for

[   218.171] (WW) AMDGPU(0): Unable to find initial modes
[   218.171] (EE) AMDGPU(0): Output DisplayPort-3 enabled but has no modes
[   218.171] (EE) AMDGPU(0): Output HDMI-A-1 enabled but has no modes

because

[   218.152] (II) AMDGPU(0): No remaining probed modes for output DisplayPort-3
[   218.171] (II) AMDGPU(0): No remaining probed modes for output HDMI-A-1

=> Remove xf86-video-amdgpu, if that doesn't help, block the simpledrm device, if that also doesn't work post a complete system journal.
Add "initcall_blacklist=simpledrm_platform_driver_init" to the https://wiki.archlinux.org/title/Kernel_parameters

sudo journalctl -b | curl -F 'file=@-' 0x0.st

It's not supposed to contain any sensitive data (though sometimes routeable IPv6 addresses are listed and all sudo calls get audited w/ their parameters) and ftr, the disk UUIDs are for collision prevention, they're unique but don't reveal anything else.

Turns out that downgrading to kernel 6.10.10 allows me to configure xrandr successfully. I will probe the problem more and report upstream when I have more time. Thanks for all the help you suggested and have a nice day!!