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This is the output of the two commands:
[demo@demo-hp ~]$ modprobe -c | grep -v alias | grep -E 'nvidia|nouveau'
blacklist nouveau
blacklist nouveau
options nouveau modeset=0
options nvidia_drm modeset=1
[demo@demo-hp ~]$ pacman -Ql nvidia-390xx-utils | grep modprobe
nvidia-390xx-utils /usr/bin/nvidia-modprobe
nvidia-390xx-utils /usr/lib/modprobe.d/
nvidia-390xx-utils /usr/lib/modprobe.d/nvidia-390xx-utils.conf
nvidia-390xx-utils /usr/share/man/man1/nvidia-modprobe.1.gzOffline
You're now blacklisting nouveau twice, "nouveau modeset=0" is pointless since it's blacklisted and "options nvidia_drm modeset=1" is as expected and means that the "nvidia_drm.modeset=1" should™ eb redundant.
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I deleted the file /etc/modprobe.d/nouveau.conf and was able to boot with the nvidia driver loaded, but if i remove nvidia-drm.modeset=1 from /etc/default/grub it still loads the graphical interface with one available resolution: 640x480
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That sounds as if the nvidia module provides special meaning to the kernel parameter now (since the parameter itself gets set via modprobe) - regardless of the simpledrm hack.
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