Ubuntu – Unable to use the 4k monitor at maximum resolution when used with one or two others FHD monitors

4k-monitorawesomemultiple-monitorsradeonxorg

I would like to use my 40" 4k monitor (Philips BDM4065UC) alongside with two others WUXGA monitors (Dell U2412M).

I can successfully run :

  • my main 4k alone at 3840×2160@60Hz,
  • or my main 4k at 2560×1440@60Hz with the two others monitors at 1920×1200@60.

As soon as, I try to increase the resolution of my main monitor to 3840×2160 with the two others monitors :

  • all the windows of the 4k monitors are grayed out,
  • the two others monitors are working correctly,
  • the mouse on the 4k monitor is still working,
  • I can move windows in and out my 4k screen but I can't see them displayed on the 4k screen.

This setup works correctly on windows.

My setup :

  • Graphic card : AMD Radeon R7 250X (same issue with 59 280X)
  • Driver : radeon (open source, don't want to use fglrx as I only do 2D stuffs)
  • Xubuntu 14.04
  • Kernel : 3.19.0-22-generic(tried also with 3.16)
  • Windows manager : Awesome WM

My configuration files :

Script 1 : xrandr script that fails :

xrandr --output DisplayPort-0 --pos 1200x0 --rotate normal --rate 60 --mode 3840x2160 --primary && \
xrandr --output HDMI-0 --auto --rotate left --pos 0x0  && \
xrandr --output DVI-0 --rate 60 --mode 1920x1200 --pos 5040x0 --rotate left 

Script 2 : xrandr script that "works" :

xrandr --output DisplayPort-0 --pos 1200x0 --rotate normal --rate 60 --mode 2560x1440 --primary && \
xrandr --output HDMI-0 --auto --rotate left --pos 0x0  && \
xrandr --output DVI-0 --rate 60 --mode 1920x1200 --pos 5040x0 --rotate left 

My logs files:

I have no errors in /var/log/Xorg.0.log.

However when digging in /var/log/syslog, I can see some errors (but are not always reproducible) :

when running Script 1 :

pcp kernel: [ 6337.304231] radeon 0000:04:00.0: ffff880390d22800 pin failed
pcp kernel: [ 6337.304231] radeon 0000:04:00.0: ffff880390d22800 pin failed
pcp kernel: [ 6337.350587] radeon 0000:04:00.0: ffff880390d22800 pin failed
pcp kernel: [ 6337.350587] radeon 0000:04:00.0: ffff880390d22800 pin failed

when running Script 2 :

pcp kernel: [ 6377.757518] radeon 0000:04:00.0: ffff880390d22800 unpin not necessary
pcp kernel: [ 6377.757518] radeon 0000:04:00.0: ffff880390d22800 unpin not necessary

It seems to be a kernel or driver issue, but I don't know where to start to debug this.

Unsuccessfull solutions:

1/ use a more powerful graphic gard : Radeon R9 280X (note: this works on windows)

2/ use a more recent kernel (3.19.0-22-generic instead of 3.16)

sudo apt-get install linux-generic-lts-vivid
sudo update-grub

3/ use a static Xorg configuration file in [/etc/X11/xorg.conf](http://paste.ubuntu.com/11914522/
)

4/ use an updated radeon driver

sudo add-apt-repository ppa:oibaf/graphics-drivers && sudo aptitude update && sudo aptitude upgrade

then removed with

sudo apt-get install ppa-purge && sudo ppa-purge ppa:oibaf/graphics-drivers && supo aptitude update && sudo aptitude upgrade

5/ upgrade to Xubuntu 15.05

same problem, even with kernel 4.0, or latest xorg / ATI packages

6/ test others distributions Mint, Debian

Partially successfull solutions:

1/ I finally give a try to the proprieratery driver. I followed the installation instructions.

The all 3 monitors are now using the appropriate screen resolutions.

However, this is now so slooow, moving the mouse is very lagguy, opening two terminal windows takes 5 seconds…

Definitly unusable…

Any hints are welcome,

Regards,

Best Answer

  • Finally got it...

    Triple check the output of /var/log/Xorg.0.log to remove as most as you can errors and warning. I mispelled one of my output DVI-O instead of DVI-0...

    So, if you encounter this problem, the solution seems to be :

    Describe as most as you can your configuration in /etc/X11/xorg.conf :

    • device section with Options "AccelMethod" "glamor" / Option "ShadowPrimary" / Option "TearFree"
    • all outputs of your video card and all your attached monitors

    Here is the fully functionnal version of my /etc/X11/xorg.conf