Thank you very much for your support. So far I have found this:
# lspci | grep VGA
01:00.0 VGA compatible controller: NVIDIA Corporation GF114M [GeForce GTX 675M] (rev a1)
I uninstalled the nouveau drivers because I found that the proprietary Nvidia drivers have a configuration tool themselves. After a reboot recommended in Arch wiki Xorg :0 -configure produced a fresh /var/log/Xorg.0.log where I could read:
NVIDIA: The NVIDIA GeForce GTX 675M GPU installed in this system is supported through the NVIDIA 390.xx Legacy drivers. [...]
[...] The 440.82 NVIDIA driver will ignore this GPU.
So I removed the nvidia drivers and installed the following
nvidia-390xx
nvidia-390xx-settings
nvidia-390xx-utils
I avoided nvidia-390xx-dkms because I read that I sould use this only with custom linux kernel.
After another Xorg :0 -configure I read in the Xorg.0.log
NVIDIA: Failed to initialize the NVIDIA kernel module. Please see the system's kernel log for additional error messages and consult the NVIDIA README for details.
That was not much of a surprise because at this time I had not configured the nvidia drivers in any way. So I ran
nvidia-xconfig --xconfig=/root/xorg.conf.new
Then I ran diff to see what changes it made. Except for changing the irrelevant indentation it removed BusID "PCI:1:0:0" in the device section. X.Org Wiki writes that this field is usually optional in single-head configurations when using the primary graphics card.
I modified and split the xorg.conf.new into sections which I placed in xorg.conf.d
# ls /etc/X11/xorg.conf.d
10-server conf 20-nvidia.conf 30-monitor.conf 40-modules.conf
they combine to this:
# cat /etc/X11/xorg.conf.d/*
Section "ServerLayout"
Identifier "Manually configured"
Screen "Laptop Screen"
InputDevice "Mouse0" "CorePointer"
InputDevice "Keyboard0" "CoreKeyboard"
EndSection
Section "InputDevice"
Identifier "Keyboard0"
Driver "kbd"
EndSection
Section "InputDevice"
Identifier "Mouse0"
Driver "mouse"
Option "Protocol" "auto"
Option "Device" "/dev/input/mice"
Option "ZAxisMapping" "4 5 6 7"
EndSection
Section "Device"
Identifier "Nvidia Card"
Driver "nvidia"
VendorName "NVIDIA Corporation"
EndSection
Section "Monitor"
Identifier "Laptop LCD"
VendorName "Samsung"
DisplaySize 381 215
EndSection
Section "Screen"
Identifier "Laptop Screen"
Device "Nvidia Card"
Monitor "Laptop LCD"
DefaultDepth 24
SubSection "Display"
Modes "1920x1080"
Depth 24
EndSubSection
EndSection
Section "Module"
Load "glx"
EndSection
xinit now produces this error log
[ 13391.789] (WW) Failed to open protocol names file lib/xorg/protocol.txt
[ 13391.790]
X.Org X Server 1.20.8
X Protocol Version 11, Revision 0
[ 13391.790] Build Operating System: Linux Artix Linux
[ 13391.790] Current Operating System: Linux lappi 5.6.3-artix1-1 #1 SMP PREEMPT Wed, 08 Apr 2020 15:06:10 +0000 x86_64
[ 13391.790] Kernel command line: BOOT_IMAGE=/vmlinuz-linux root=UUID=16211fe2-0927-4853-af22-b701645183fd rw loglevel=3 random.trust_cpu=on resume=UUID=8a8c0b83-8b6f-4fea-bd4a-905e7b51ebb4 quiet
[ 13391.791] Build Date: 30 March 2020 02:12:50PM
[ 13391.791]
[ 13391.791] Current version of pixman: 0.38.4
[ 13391.792] Before reporting problems, check http://wiki.x.org
to make sure that you have the latest version.
[ 13391.792] Markers: (--) probed, (**) from config file, (==) default setting,
(++) from command line, (!!) notice, (II) informational,
(WW) warning, (EE) error, (NI) not implemented, (??) unknown.
[ 13391.793] (==) Log file: "/var/log/Xorg.0.log", Time: Wed Apr 22 06:14:00 2020
[ 13391.793] (==) Using config directory: "/etc/X11/xorg.conf.d"
[ 13391.794] (==) Using system config directory "/usr/share/X11/xorg.conf.d"
[ 13391.794] (==) ServerLayout "Manually configured"
[ 13391.794] (**) |-->Screen "Laptop Screen" (0)
[ 13391.794] (**) | |-->Monitor "Laptop LCD"
[ 13391.794] (**) | |-->Device "Nvidia Card"
[ 13391.794] (**) |-->Input Device "Mouse0"
[ 13391.794] (**) |-->Input Device "Keyboard0"
[ 13391.794] (==) Automatically adding devices
[ 13391.794] (==) Automatically enabling devices
[ 13391.794] (==) Automatically adding GPU devices
[ 13391.794] (==) Automatically binding GPU devices
[ 13391.794] (==) Max clients allowed: 256, resource mask: 0x1fffff
[ 13391.794] (WW) `fonts.dir' not found (or not valid) in "/usr/share/fonts/misc".
[ 13391.794] Entry deleted from font path.
[ 13391.794] (Run 'mkfontdir' on "/usr/share/fonts/misc").
[ 13391.794] (WW) The directory "/usr/share/fonts/TTF" does not exist.
[ 13391.794] Entry deleted from font path.
[ 13391.794] (WW) The directory "/usr/share/fonts/OTF" does not exist.
[ 13391.794] Entry deleted from font path.
[ 13391.794] (WW) The directory "/usr/share/fonts/Type1" does not exist.
[ 13391.794] Entry deleted from font path.
[ 13391.794] (==) FontPath set to:
/usr/share/fonts/100dpi,
/usr/share/fonts/75dpi
[ 13391.794] (==) ModulePath set to "/usr/lib/xorg/modules"
[ 13391.794] (WW) Hotplugging is on, devices using drivers 'kbd', 'mouse' or 'vmmouse' will be disabled.
[ 13391.794] (WW) Disabling Mouse0
[ 13391.794] (WW) Disabling Keyboard0
[ 13391.794] (II) Module ABI versions:
[ 13391.794] X.Org ANSI C Emulation: 0.4
[ 13391.794] X.Org Video Driver: 24.1
[ 13391.794] X.Org XInput driver : 24.1
[ 13391.794] X.Org Server Extension : 10.0
[ 13391.795] (--) using VT number 7
[ 13391.795] (II) systemd-logind: logind integration requires -keeptty and -keeptty was not provided, disabling logind integration
[ 13391.797] (--) PCI:*(1@0:0:0) 10de:1212:144d:c0d0 rev 161, Mem @ 0xf6000000/16777216, 0xec000000/67108864, 0xf0000000/33554432, I/O @ 0x0000e000/128, BIOS @ 0x????????/131072
[ 13391.797] (WW) Open ACPI failed (/var/run/acpid.socket) (No such file or directory)
[ 13391.797] (II) "glx" will be loaded. This was enabled by default and also specified in the config file.
[ 13391.797] (II) LoadModule: "glx"
[ 13391.797] (II) Loading /usr/lib/xorg/modules/extensions/libglx.so
[ 13391.798] (II) Module glx: vendor="X.Org Foundation"
[ 13391.798] compiled for 1.20.8, module version = 1.0.0
[ 13391.798] ABI class: X.Org Server Extension, version 10.0
[ 13391.798] (II) LoadModule: "nvidia"
[ 13391.798] (II) Loading /usr/lib/xorg/modules/drivers/nvidia_drv.so
[ 13391.798] (II) Module nvidia: vendor="NVIDIA Corporation"
[ 13391.798] compiled for 4.0.2, module version = 1.0.0
[ 13391.798] Module class: X.Org Video Driver
[ 13391.798] (II) NVIDIA dlloader X Driver 390.132 Fri Nov 1 03:36:28 PDT 2019
[ 13391.798] (II) NVIDIA Unified Driver for all Supported NVIDIA GPUs
[ 13391.799] (II) Loading sub module "fb"
[ 13391.799] (II) LoadModule: "fb"
[ 13391.799] (II) Loading /usr/lib/xorg/modules/libfb.so
[ 13391.800] (II) Module fb: vendor="X.Org Foundation"
[ 13391.800] compiled for 1.20.8, module version = 1.0.0
[ 13391.800] ABI class: X.Org ANSI C Emulation, version 0.4
[ 13391.800] (II) Loading sub module "wfb"
[ 13391.800] (II) LoadModule: "wfb"
[ 13391.800] (II) Loading /usr/lib/xorg/modules/libwfb.so
[ 13391.800] (II) Module wfb: vendor="X.Org Foundation"
[ 13391.800] compiled for 1.20.8, module version = 1.0.0
[ 13391.800] ABI class: X.Org ANSI C Emulation, version 0.4
[ 13391.800] (II) Loading sub module "ramdac"
[ 13391.800] (II) LoadModule: "ramdac"
[ 13391.800] (II) Module "ramdac" already built-in
[ 13391.804] (EE) NVIDIA: Failed to initialize the NVIDIA kernel module. Please see the
[ 13391.804] (EE) NVIDIA: system's kernel log for additional error messages and
[ 13391.804] (EE) NVIDIA: consult the NVIDIA README for details.
[ 13391.804] (EE) No devices detected.
[ 13391.804] (EE)
Fatal server error:
[ 13391.804] (EE) no screens found(EE)
[ 13391.804] (EE)
Please consult the The X.Org Foundation support
at http://wiki.x.org
for help.
[ 13391.804] (EE) Please also check the log file at "/var/log/Xorg.0.log" for additional information.
[ 13391.804] (EE)
[ 13391.808] (EE) Server terminated with error (1). Closing log file.
Somehow the Nvidia kernel module doesn't load. I don't know why. Is there a way to further debug this? As a workaround, I might try to uninstall the nvidia's legacy drivers and install xf86-video-nouveau instead and try with that. But before I do that, I want to use the nvidia-settings tool to find out more about the card, maybe it's missing something in my xorg.conf files