I just bought a 4K monitor, Dell’s UP2414Q. The 182ppi screen covering 99% of AdobeRGB looks absolutely stunning. But I’m having some trouble getting it to work at its peak and consistently.
First of all, how do I enable 60hz? The monitor can reach that with DisplayPort 1.2.
The monitor/GPU defaults to 30hz via DisplayPort in both SST, and MST when enabling DP 1.2 from screen OSD menu. HDMI can’t do 60hz at 4K, so haven’t tried. nVidia control panel doesn’t have any place to change refresh rate, and neither does Display under Settings.
I checked xrandr output, and it gives the following with DP 1.2 disabled (I didn’t paste lower resolutions):
DP-1 connected primary 3840x2160+0+0 (normal left inverted right x axis y axis) 527mm x 296mm 3840x2160 30.0*+ 30.3
This shows the correct 4K resolution, but “30.0*+” as the available refresh rate. This is as expected, since the display shouldn’t be able to do 60hz without 1.2 enabled.
When I enable DP 1.2 from the monitor’s OSD, I get the following output:
DP-1 disconnected primary 3840x2160+0+0 (normal left inverted right x axis y axis) 0mm x 0mm 3840x2160 (0x284) 262.8MHz h: width 3840 start 3888 end 3920 total 4000 skew 0 clock 65.7KHz v: height 2160 start 2163 end 2168 total 2191 clock 30.0Hz
This is quite different output, and I’m not sure how to read it. But it also says 30Hz, not 60Hz - and the monitor should be able to do 60Hz at this setup.
When I try to force 60Hz with xrandr --output DP-1 --rate 60.0, I get:
X Error of failed request: BadMatch (invalid parameter attributes) Major opcode of failed request: 140 (RANDR) Minor opcode of failed request: 21 (RRSetCrtcConfig) Serial number of failed request: 40 Current serial number in output stream: 40
Secondly, when I turn on my projector fed by HDMI port, both screens go blank if the monitor is set to MST/DP1.2. If the monitor is in SST mode (i.e. DisplayPort 1.2 is disabled), both the monitor and projector work fine in Twinview. Any idea how to tackle this?
Running Linux Mint Petra with Nemo, nVidia GTX 760. Tried with two drivers: nvidia-139 Version 319.32-0ubuntu7 “recommended”, and nvidia-319-updates Version 319.60-0ubuntu1.