4 Replies Latest reply on Dec 26, 2016 12:09 PM by Intel Corporation

    3840x2160 60hz 5i3RYK

    patdan

      Hello I can't manage to run 3840x2160 at 60hz from my NUC.

      I have a converter from mini DP to HDMI 2.0 and then a HDMI 2.0 cable to my tv.

      60 hz works with this setup if I use my laptop instead (which has a mini DP).

      Both are running pretty much identical systems of Arch Linux.

      Any clues to why this fails?

        • 1. Re: 3840x2160 60hz 5i3RYK
          Lokutos

          Which converter do you have? It must be an active one. I use the Club 3D mini-DP to HDMI 2.0 one with good results (on Arch). You have to use reduced blanking timings as (for whatever reason) the NUC can only use a pixel clock of about 540 MHz.

          For example this works for me:

          xrandr --newmode "3840x2160_59.95" 533.6 3840 3982 4027 4064 2160 2170 2180 2190 +hsync +vsync

          xrandr --addmode DP1 "3840x2160_59.95"

          xrandr --output DP1 --mode "3840x2160_59.95"

           

          I used 59.95Hz timings as that is 2.5 times the usual film frame rate.

          On my TV I had to disable Deep Color (HDR signaling) on the HDMI port. I'm not sure why, as the HDMI converter is said to be able to do color space conversions (e.g. from 4:4:4 to 4:2:0). Maybe the DP bandwidth is too high for the NUC's cdclk limit.

          Also there is some code in the i915 driver which adjust cdlk for Broadwell but currently uses a limit of 540MHz, even though with adequate cooling (which I'm sure the NUC has) a limit of 675MHz is allowed. It's just that the code doesn't know whether the cooling solution has enough headroom. You could easily patch that part and have a higher cdclk limit. (see function intel_update_max_cdclk() in intel_display.c)

          • 2. Re: 3840x2160 60hz 5i3RYK
            Intel Corporation
            This message was posted on behalf of Intel Corporation

            Please bear in mind that Intel limits the support for Linux operating system.
            I would recommend checking for Linux drivers at: https://01.org/linuxgraphics/downloads/2013/intelr-graphics-installer-1.0.1-linux

            Some customers have reported that ArchLinux* has been working properly on your Intel® NUC
            http://www.intel.com/content/www/us/en/support/boards-and-kits/intel-nuc-boards/000005628.html

            Allan.


             

            • 3. Re: 3840x2160 60hz 5i3RYK
              patdan

              Thanks for your reply! The adapter works as I have tried it successfully on my laptop. I tried creating a new resolution with reduced blanking, both 59.95 and 60 but no dice. I have sent it for an RMA to check if there's something wrong with it.

              • 4. Re: 3840x2160 60hz 5i3RYK
                Intel Corporation
                This message was posted on behalf of Intel Corporation

                Thank you for updating the thread with this information.

                Allan.