I have a Thinkpad T440s running 15.04 with the Intel HD 4400 graphics. I just got a 4K monitor (Dell P2415Q). According to the specs of the HD4400, I should be able to drive this monitor at 30hz at 4K resolution. I have used this computer to do exactly that. Note that I am connecting via displayport.
Running xrandr gives
Screen 0: minimum 8 x 8, current 4480 x 1440, maximum 32767 x 32767
eDP1 connected primary 1920x1080+0+360 (normal left inverted right x axis y axis) 309mm x 173mm
1920x1080 60.0*+ 59.9
1680x1050 60.0 59.9
1600x1024 60.2
1400x1050 60.0
1280x1024 60.0
1440x900 59.9
1280x960 60.0
1360x768 59.8 60.0
1152x864 60.0
1024x768 60.0
800x600 60.3 56.2
640x480 59.9
DP1 connected 2560x1440+1920+0 (normal left inverted right x axis y axis) 527mm x 296mm
3840x2160 60.0 +
2560x1440 60.0*
2048x1280 60.0
1920x1200 59.9
1920x1080 60.0 60.0 50.0 59.9 30.0 25.0 24.0 30.0 24.0
1920x1080i 60.1 50.0 60.0
1600x1200 60.0
1600x900 60.0
1280x1024 75.0 60.0
1152x864 75.0
1280x720 60.0 50.0 59.9
1024x768 75.1 60.0
800x600 75.0 60.3
720x576 50.0
720x480 60.0 59.9
640x480 75.0 60.0 59.9
720x400 70.1
DP2 disconnected (normal left inverted right x axis y axis)
HDMI1 disconnected (normal left inverted right x axis y axis)
HDMI2 disconnected (normal left inverted right x axis y axis)
VIRTUAL1 disconnected (normal left inverted right x axis y axis)
It seems like I need to add a mode to run 3840x2160 at 30 Hz.
cvt 3840 2160 30
# 3840x2160 29.98 Hz (CVT) hsync: 65.96 kHz; pclk: 338.75 MHz
Modeline "3840x2160_30.00" 338.75 3840 4080 4488 5136 2160 2163 2168 2200 -hsync +vsync
Proceeding:
xrandr --newmode "3840x2160_30.00" 338.75 3840 4080 4488 5136 2160 2163 2168 2200 -hsync +vsync
xrandr --verbose --addmode DP1 "3840x2160_30.00"
Finally:
xrandr --output DP1 --mode "3840x2160_30.00"
When I do this, the monitor flickers for a second, then goes back to 2560x1440 @ 60hz. Running xrandr again:
Screen 0: minimum 8 x 8, current 4480 x 1440, maximum 32767 x 32767
eDP1 connected primary 1920x1080+0+360 (normal left inverted right x axis y axis) 309mm x 173mm
1920x1080 60.0*+ 59.9
1680x1050 60.0 59.9
1600x1024 60.2
1400x1050 60.0
1280x1024 60.0
1440x900 59.9
1280x960 60.0
1360x768 59.8 60.0
1152x864 60.0
1024x768 60.0
800x600 60.3 56.2
640x480 59.9
DP1 connected 2560x1440+1920+0 (normal left inverted right x axis y axis) 527mm x 296mm
3840x2160 60.0 +
2560x1440 60.0*
2048x1280 60.0
1920x1200 59.9
1920x1080 60.0 60.0 50.0 59.9 30.0 25.0 24.0 30.0 24.0
1920x1080i 60.1 50.0 60.0
1600x1200 60.0
1600x900 60.0
1280x1024 75.0 60.0
1152x864 75.0
1280x720 60.0 50.0 59.9
1024x768 75.1 60.0
800x600 75.0 60.3
720x576 50.0
720x480 60.0 59.9
640x480 75.0 60.0 59.9
720x400 70.1
3840x2160_30.00 30.0
DP2 disconnected (normal left inverted right x axis y axis)
HDMI1 disconnected (normal left inverted right x axis y axis)
HDMI2 disconnected (normal left inverted right x axis y axis)
VIRTUAL1 disconnected (normal left inverted right x axis y axis)
Not sure what to do from here. Is this a hardware issue? Am I doing something wrong?