4K support not working?

[MrMEEE]

Hi guys

I have an weird issue trying to get a 27" 4K monitor to work with my Lenovo X240...

The X240 is supposed to be able to support 4K (3820x2160), but only at 30hz...

But every time I try to switch to 4k, the screen goes black... it doesn't not go into sleep mode, so it seems like it's receiving something from the machine, and the xrandr info also seems correct:

Screen 0: minimum 8 x 8, current 4480 x 2160, maximum 32767 x 32767
eDP1 connected primary 1920x1080+2560+0 (normal left inverted right x axis y axis) 276mm x 156mm
   1920x1080 60.04*+ 59.93
   1680x1050 59.95 59.88
   1600x1024 60.17
   1400x1050 59.98
   1600x900 60.00
   1280x1024 60.02
   1440x900 59.89
   1280x960 60.00
   1368x768 60.00
   1360x768 59.80 59.96
   1152x864 60.00
   1280x720 60.00
   1024x768 60.00
   1024x576 60.00
   960x540 60.00
   800x600 60.32 56.25
   864x486 60.00
   640x480 59.94
   720x405 60.00
   640x360 60.00
DP1 disconnected (normal left inverted right x axis y axis)
DP2 disconnected (normal left inverted right x axis y axis)
DP2-1 connected 3840x2160+0+0 (normal left inverted right x axis y axis) 597mm x 336mm
   3840x2160 60.00*+ 29.98
   2560x1440 59.95
   1920x1200 59.88
   1920x1080 60.00 50.00 59.94 24.00 23.98
   1600x1200 60.00
   1680x1050 59.95
   1280x1024 75.02 60.02
   1280x800 59.81
   1152x864 75.00
   1280x720 60.00 50.00 59.94
   1024x768 75.08 60.00
   800x600 75.00 60.32
   720x576 50.00
   720x480 60.00 59.94
   640x480 75.00 60.00 59.94
   720x400 70.08
DP2-2 disconnected (normal left inverted right x axis y axis)
DP2-3 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)

All other resolutions works fine.. also 2560x1440...

I have tried to connect the monitor through the mDP directly on the machine, and through DP and HDMI on the dock.. on HDMI the 2560x1440 resolution isn't available, but on all the 4k resolution resolves in a black screen....

Hope that someone can help...

[MrMEEE (mj-casalogic)]

I have just testet this on Windows 7, and it works fine...

So I presume it's a bug in the Linux driver/kernel?????

[penalvch (penalvch)]

MrMEEE, thank you for reporting this and helping make Ubuntu better.

Could you please run the following command once from a terminal as it will automatically gather and attach updated debug information to this report:
apport-collect -p xorg 1512386

Please ensure you have the package xdiagnose installed, and that you click the Yes button for attaching additional debugging information.

When reporting xorg related bugs in the future, please do so via the above method. You can learn more about this functionality at https://wiki.ubuntu.com/ReportingBugs.

[MIME (whatifmaybe)]

Hi Christopher,

Please count me in. I am using a Lenovo X250 and can't use 4k anymore.
Some weeks ago / some updates before it was working if the notebook was connected directly via DisplayPort.
4k via Lenovo Dock was never working.

System settings still offer 4k resolution but screen keeps black.

Thanks!

[MrMEEE (mj-casalogic)]

Hi

My X240 broke... so I got a X250 instead... on which the 4K didn't work either with 15.10.... but today I have just installed the newest mainline kernel (4.5.0-040500rc4_4.5.0-040500rc4)... and suddenly it works!!! :)

[penalvch (penalvch)]

MIME, it will help immensely if you filed a new report with Ubuntu by ensuring you have the package xdiagnose installed, and that you click the Yes button for attaching additional debugging information running the following from a terminal:
ubuntu-bug xorg

Also, please feel free to subscribe me to it.

For more on why this is helpful, please see https://wiki.ubuntu.com/ReportingBugs.

[penalvch (penalvch)]

MrMEEE, this bug report is being closed due to your last comment https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1512386/comments/3 regarding you no longer have the originally reported hardware (X240). For future reference you can manage the status of your own bugs by clicking on the current status in the yellow line and then choosing a new status in the revealed drop down box. You can learn more about bug statuses at https://wiki.ubuntu.com/Bugs/Status.

Regarding your X250, it will help immensely if you filed a new report with the Ubuntu repository kernel (not mainline/upstream) via a terminal:
ubuntu-bug linux

Please feel free to subscribe me to it.

For more on why this is helpful, please see https://wiki.ubuntu.com/ReportingBugs.

Thank you again for taking the time to report this bug and helping to make Ubuntu better. Please submit any future bugs you may find.