@nightmare-2021 on my GTX1650 I am not able to start SDDM anymore. I thought it was related to modeset, and I have disabled it by removing nvidia-drm.modeset=1 from the kernel line. I also removed everything related to fbcon and even vesafb.
The result is that the system starts with a very slow text console, and in the moment SDDM starts, it just hangs on a black screen.
From my journal:
Apr 22 22:49:16 <hostname> sddm[1309]: Initializing...
Apr 22 22:49:16 <hostname> sddm[1309]: Starting...
Apr 22 22:49:16 <hostname> sddm[1309]: Logind interface found
Apr 22 22:49:16 <hostname> sddm[1309]: Adding new display on vt 1 ...
Apr 22 22:49:16 <hostname> sddm[1309]: Loading theme configuration from ""
Apr 22 22:49:16 <hostname> sddm[1309]: Display server starting...
Apr 22 22:49:16 <hostname> sddm[1309]: Adding cookie to "/var/run/sddm/{a3235f7a-754f-4c9e-903a-3605868d1206}"
Apr 22 22:49:16 <hostname> sddm[1309]: Running: /usr/bin/X -nolisten tcp -background none -seat seat0 vt1 -auth /var/run/sddm/{a3235f7a-754f-4c9e-903a-3605868d1206} -noreset -displayfd 17
Apr 22 22:49:16 <hostname> acpid[971]: client connected from 1312[0:0]
Apr 22 22:49:16 <hostname> acpid[971]: 1 client rule loaded
Apr 22 22:49:16 <hostname> kernel: resource sanity check: requesting [mem 0x000c0000-0x000fffff], which spans more than PCI Bus 0000:00 [mem 0x000d0000-0x000dffff window]
Apr 22 22:49:16 <hostname> kernel: caller _nv000712rm+0x1af/0x200 [nvidia] mapping multiple BARs
Apr 22 22:49:20 <hostname> kernel: BUG: kernel NULL pointer dereference, address: 0000000000000170
Apr 22 22:49:20 <hostname> kernel: #PF: supervisor read access in kernel mode
Apr 22 22:49:20 <hostname> kernel: #PF: error_code(0x0000) - not-present page
And then I have to hard reset.