I use setupCommands/sessionCommands as a workaround to use a resolution where xfce4 at least displays something instead of a blank screen:
services = {
xserver = {
enable = true;
displayManager = {
setupCommands="/run/current-system/sw/bin/xrandr --output HDMI-1 --mode 1920x1080 --rate 60";
sessionCommands="/run/current-system/sw/bin/xrandr --output HDMI-1 --mode 1920x1080 --rate 60";
This works in 25.05, but does no longer in 25.11. With the latter I can login to lightdm, but after that, an unsupported resolution is chosen.
Debian 13 on the same hardware runs fine in 2560x1440
The Monitor is a DELL U2715H.
# lspci
01:00.0 VGA compatible controller: NVIDIA Corporation GF108M [GeForce GT 425M] (rev a1)
# lshw -c display
*-display
product: nouveaudrmfb
physical id: 0
bus info: pci@0000:01:00.0
logical name: /dev/fb0
version: a1
width: 64 bits
clock: 33MHz
capabilities: pm msi pciexpress bus_master cap_list rom fb
configuration: depth=32 driver=nouveau latency=0 resolution=2048,1152
resources: irq:36 memory:fa000000-faffffff memory:d8000000-dfffffff memory:d6000000-d7ffffff ioport:dc00(size=128) memory:c0000-dffff
xrandr on NixOS reports this as largest resolution:
2048x1152 (0x43) 302.500MHz +HSync -VSync DoubleScan
2048x1152 (0x44) 197.000MHz -HSync +VSync
2048x1152 (0x45) 162.000MHz +HSync +VSync
2048x1152 (0x46) 156.750MHz +HSync -VSync
# parse-edid < /sys/class/drm/card0-HDMI-A-1/edid
Checksum Correct
Section "Monitor"
Identifier "DELL U2715H"
ModelName "DELL U2715H"
VendorName "DEL"
# EDID version 1.3
# Digital Display
DisplaySize 600 340
Gamma 2.20
Option "DPMS" "true"
Horizsync 30-113
VertRefresh 56-86
# Maximum pixel clock is 300MHz
#Not giving standard mode: 1680x1050, 60Hz
#Not giving standard mode: 1920x1200, 60Hz
#Not giving standard mode: 1152x864, 75Hz
#Not giving standard mode: 1600x1200, 60Hz
#Not giving standard mode: 1280x1024, 60Hz
#Not giving standard mode: 1200x960, 60Hz
#Extension block found. Parsing...
Modeline "Mode 16" +hsync +vsync
Modeline "Mode 0" +hsync -vsync
Modeline "Mode 1" 148.500 1920 2008 2052 2200 1080 1084 1089 1125 +hsync +vsync
Modeline "Mode 2" 74.250 1920 2008 2052 2200 1080 1082 1087 1125 +hsync +vsync interlace
Modeline "Mode 3" 74.250 1280 1390 1420 1650 720 725 730 750 +hsync +vsync
Modeline "Mode 4" 27.027 720 736 798 858 480 489 495 525 -hsync -vsync
Modeline "Mode 5" 27.027 720 736 798 858 480 489 495 525 -hsync -vsync
Modeline "Mode 6" 27.027 1440 1478 1602 1716 480 484 487 525 -hsync -vsync interlace
Modeline "Mode 7" 27.000 1440 1464 1590 1728 576 578 581 625 -hsync -vsync interlace
Modeline "Mode 8" 25.200 640 656 752 800 480 490 492 525 -hsync -vsync
Modeline "Mode 9" 74.250 1920 2448 2492 2640 1080 1082 1089 1125 +hsync +vsync interlace
Modeline "Mode 10" 148.500 1920 2448 2492 2640 1080 1084 1089 1125 +hsync +vsync
Modeline "Mode 11" 27.000 720 732 796 864 576 581 586 625 -hsync -vsync
Modeline "Mode 12" 74.250 1280 1720 1760 1980 720 725 730 750 +hsync +vsync
Modeline "Mode 13" 74.250 1920 2558 2602 2750 1080 1084 1089 1125 +hsync +vsync
Modeline "Mode 14" 74.250 1920 2448 2492 2640 1080 1084 1089 1125 +hsync +vsync
Modeline "Mode 15" 74.250 1920 2008 2052 2200 1080 1084 1089 1125 +hsync +vsync
Modeline "Mode 17" +hsync +vsync interlace
Modeline "Mode 18" +hsync +vsync
Modeline "Mode 19" -hsync -vsync
Option "PreferredMode" "Mode 16"
EndSection