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chroniclesoffire

Member

Registered: 2026-01-07

Posts: 4

[SOLVED] lightdm does not display on laptop

When booting my system, or any other time, really, lightdm will not display on my laptop screen.  However, if I plug a monitor into the back port of the laptop which specifically ties to the dGPU, that monitor will display the lightdm.  this is how I've been getting around the issue.

This is a new laptop, a Framework 16 with the Radeon 7700S dGPU option.  It runs the Ryzen AI 9 HX 370 + Radeon 890M iGPU.   I suspect it has something to do with the GPU not loading the laptop screen correctly, but, I can't really tell which GPU is supposed to be handling it, especially since that are both using the amdgpu driver.

lspci output: http://0x0.st/PHGW.txt
dmesg output: https://0x0.st/PHDs.txt
journalctl -b output: http://0x0.st/PHD-.txt
Xorg.0.log: http://0x0.st/PHDo.txt

The Xorg log has an interesting line:
[     7.565] (EE) open /dev/dri/card0: No such file or directory

there is indeed no card0 in that directory, but there is a card1 and card2.

is something getting skipped somehow during boot?

Last edited by chroniclesoffire (2026-01-09 20:28:04)

seth

Member

From: Don't DM me only for attention

Registered: 2012-09-03

Posts: 72,057

Re: [SOLVED] lightdm does not display on laptop

card0 was snatched by the simpledrm device

[     7.659] (II) AMDGPU(0): Output eDP has no monitor section
[     7.660] (II) AMDGPU(0): EDID for output eDP
[     7.660] (II) AMDGPU(0): Output eDP disconnected
[     7.660] (II) AMDGPU(0): Output eDP disconnected
[     7.675] (II) AMDGPU(G0): Output eDP-1-1 has no monitor section
[     7.696] (II) AMDGPU(G0): EDID for output eDP-1-1
[     7.696] (II) AMDGPU(G0): Printing probed modes for output eDP-1-1

The server is running on the AMD Radeon RX 7700S, the eDP is wired to the Radeon 890M

Assuming that's not intended and because of the BUS IDs (the autoconfig doesn't seem to be good at guessing those) try to add
/etc/X11/xorg.conf.d/20-amdapu.conf

Section "Device"
        Identifier "APU"
        Driver "amdgpu"
        BusID "PCI:196:0:0"
EndSection

Section "Screen"
        Identifier "APU"
        Device "APU"
EndSection

Also remove every xf86-video-* package except for xf86-video-amdgpu

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chroniclesoffire

Member

Registered: 2026-01-07

Posts: 4

Re: [SOLVED] lightdm does not display on laptop

Awesome! that conf file did the trick. 
I'm going to remove the uneeded xf86 packages now as well.

Question, is the code line

        BusID "PCI:196:0:0" 

arcane knowledge, or is there documentation about that?  I swore I've seen that BusID before somewhere.

seth

Member

From: Don't DM me only for attention

Registered: 2012-09-03

Posts: 72,057

Re: [SOLVED] lightdm does not display on laptop

[     7.325] (--) PCI:*(195@0:0:0) 1002:7480:f111:0007 rev 193, Mem @ 0x5800000000/8589934592, 0x5a00000000/268435456, 0xb0c00000/1048576, I/O @ 0x00002000/256, BIOS @ 0x????????/131072
[     7.325] (--) PCI: (196@0:0:0) 1002:150e:f111:000d rev 193, Mem @ 0x5a10000000/268435456, 0x5a20800000/2097152, 0xb0b00000/524288, I/O @ 0x00001000/256

(But idk, why the log syntax includes the @)

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

chroniclesoffire

Member

Registered: 2026-01-07

Posts: 4

Re: [SOLVED] lightdm does not display on laptop

Oh the Xorg log file catches the BusID when it initializes it. 
Thanks for the insight!