Arch Linux

invlogic

Member

Registered: 2014-12-23

Posts: 5

Trouble getting 4K resolution on Thinkpad X240

Would really appreciate some help.

I've had a Thinkpad X240 for about 6 months and it has been working on arch just great. However, about 2 months ago after updating the system, I could no longer get the normal 4K resolution out of my Seiki at home and Samsung at work.

I have tried messing with my Xorg config to get it working again, but it simply fails. Both the monitors only support 3840x2160 @ 30hz, and xrandr shows it as using that correctly, however the monitors will simply say "unsupported signal" or display a black screen.

Currently I don't have the monitor mentioned in my Xorg config at all. On login, I simply have a script which runs:

$ xrandr --output DP3 --right-of eDP1 --primary --auto

Where DP3 is the external monitor and eDP1 is the LCD. Around the time the issue happened, the inputs for the monitor changed from using HDMI0 to using DP3. The monitor is plugged into the laptop through a docking station (have a dock at home and at work).

I have tried reinstalling older versions of xf86-video-intel, however it didn't help. I know xorg-server has been updated a couple times, but haven't tried rolling it back.

Any help with this would be appreciated. I miss my external monitor.

blackrat

Member

From: Poland

Registered: 2014-12-10

Posts: 10

Re: Trouble getting 4K resolution on Thinkpad X240

Hey! What is you desktop environment or window manager? Maybe you can try arandr? It's a GUI for xrandr and couple of time it's help me. I have Thinkpad X201 and maybe I can help you, but first tell me what Im asking and try arandr Regards

invlogic

Member

Registered: 2014-12-23

Posts: 5

Re: Trouble getting 4K resolution on Thinkpad X240

My window manager is AwesomeWM. I don't run a full desktop environment, but have some utilities installed from gnome and some stuff like lxrandr from LXDE.

I tried arandr, but to no avail.

Output of xrandr is:

Screen 0: minimum 8 x 8, current 5760 x 2160, maximum 32767 x 32767
eDP1 connected 1920x1080+0+1080 (normal left inverted right x axis y axis) 276mm x 156mm
   1920x1080     60.04*+
   1400x1050     59.98  
   1280x1024     60.02  
   1280x960      60.00  
   1024x768      60.00  
   800x600       60.32    56.25  
   640x480       59.94  
DP1 disconnected (normal left inverted right x axis y axis)
DP2 disconnected (normal left inverted right x axis y axis)
DP3 connected primary 3840x2160+1920+0 (normal left inverted right x axis y axis) 854mm x 481mm
   3840x2160     30.00*+  25.00    24.00    29.97    23.98  
   1920x1080     60.00    50.00    59.94    24.00    23.98  
   1440x900      59.89  
   1280x960      60.00  
   1280x720      60.00    50.00    59.94  
   1024x768      75.08    70.07    60.00  
   800x600       72.19    75.00    60.32  
   720x576       50.00  
   720x480       60.00    59.94  
   640x480       75.00    72.81    60.00    59.94  
   720x400       70.08  
   3840x2160_30  30.00  
DP4 disconnected (normal left inverted right x axis y axis)
DP5 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)

So even now it should have the external monitor active, but it simply says "no signal". I don't think it is hardware, because this is with two different monitors and two separate docking stations. Also, I can run the monitors at lower resolutions just fine, so 1920x1080 on the Seiki works no problem.

The "3840x2160_30" mode mentioned is one I have my login script automatically add. When I first setup the laptop, the system kept trying to use 3840x2160 @ 60hz and didn't show a 30hz mode, but now it is the same settings as the default one, it seems.

That output is also with the monitor turned on via arandr, and have it positioned so eDP1 is the lower corner of DP3.