I've never had external monitor, and just bought an Iiyama ProLite XUB2792QSU. It connects very well to my work laptop on Windows, but not on my personal laptop (Toshiba A665-5177 from 2011) running on Ubuntu

  • No signal is detected by the monitor with HDMI plugged in (I used the brand new HDMI cable provided by the monitor)
  • I doesn't work either when trying with an HDMI-to-DisplayPort converter and a DisplayPort cable I had
  • xrandr doesn't even show HDMI ...
  • I did try to unplug and plug the cable again, to no avail

Can you help me solve this?

The laptop has no additional graphics card besides the Intel Integrated HD Graphics (see output):

user@laptop:~$ lspci | grep VGA
00:02.0 VGA compatible controller: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller (rev 09)

Extra info:

  • Initially installed xubuntu (i.e. using lightdm), with ubuntu now upgraded to 18.04.3
  • Running Ubuntu Kernel 4.15.0-72-generic
  • No xorg.conf file
user@laptop:~$ xrandr
Screen 0: minimum 320 x 200, current 1366 x 768, maximum 8192 x 8192
LVDS-1 connected primary 1366x768+0+0 (normal left inverted right x axis y axis) 345mm x 194mm
   1366x768      59.97*+
   1360x768      59.80    59.96  
   1280x720      60.00    59.99    59.86    59.74  
   1024x768      60.04    60.00  
   960x720       60.00  
   928x696       60.05  
   896x672       60.01  
   1024x576      59.95    59.96    59.90    59.82  
   960x600       59.93    60.00  
   960x540       59.96    59.99    59.63    59.82  
   800x600       60.00    60.32    56.25  
   840x525       60.01    59.88  
   864x486       59.92    59.57  
   800x512       60.17  
   700x525       59.98  
   800x450       59.95    59.82  
   640x512       60.02  
   720x450       59.89  
   700x450       59.96    59.88  
   640x480       60.00    59.94  
   720x405       59.51    58.99  
   684x384       59.88    59.85  
   680x384       59.80    59.96  
   640x400       59.88    59.98  
   576x432       60.06  
   640x360       59.86    59.83    59.84    59.32  
   512x384       60.00  
   512x288       60.00    59.92  
   480x270       59.63    59.82  
   400x300       60.32    56.34  
   432x243       59.92    59.57  
   320x240       60.05  
   360x202       59.51    59.13  
   320x180       59.84    59.32  
VGA-1 disconnected (normal left inverted right x axis y axis)
user@laptop:~$ dpkg -l | grep xorg
ii  python3-xkit                                                0.5.0ubuntu2                                       all          library for the manipulation of xorg.conf files (Python 3)
ii  xorg                                                        1:7.7+19ubuntu7.1                                  amd64        X.Org X Window System
ii  xorg-docs-core                                              1:1.7.1-1.1                                        all          Core documentation for the X.org X Window System
ii  xorg-sgml-doctools                                          1:1.11-1                                           all          Common tools for building X.Org SGML documentation
ii  xserver-xorg                                                1:7.7+19ubuntu7.1                                  amd64        X.Org X server
ii  xserver-xorg-core                                           2:1.19.6-1ubuntu4.3                                amd64        Xorg X server - core server
ii  xserver-xorg-input-all                                      1:7.7+19ubuntu7.1                                  amd64        X.Org X server -- input driver metapackage
ii  xserver-xorg-input-evdev                                    1:2.10.5-1ubuntu1                                  amd64        X.Org X server -- evdev input driver
ii  xserver-xorg-input-libinput                                 0.27.1-1                                           amd64        X.Org X server -- libinput input driver
ii  xserver-xorg-input-synaptics                                1.9.0-1ubuntu1                                     amd64        Synaptics TouchPad driver for X.Org server
ii  xserver-xorg-input-wacom                                    1:0.36.1-0ubuntu1                                  amd64        X.Org X server -- Wacom input driver
ii  xserver-xorg-legacy                                         2:1.19.6-1ubuntu4.3                                amd64        setuid root Xorg server wrapper
ii  xserver-xorg-video-all                                      1:7.7+19ubuntu7.1                                  amd64        X.Org X server -- output driver metapackage
ii  xserver-xorg-video-amdgpu                                   18.0.1-1                                           amd64        X.Org X server -- AMDGPU display driver
ii  xserver-xorg-video-ati                                      1:18.0.1-1                                         amd64        X.Org X server -- AMD/ATI display driver wrapper
ii  xserver-xorg-video-fbdev                                    1:0.4.4-1build6                                    amd64        X.Org X server -- fbdev display driver
ii  xserver-xorg-video-intel                                    2:2.99.917+git20171229-1                           amd64        X.Org X server -- Intel i8xx, i9xx display driver
ii  xserver-xorg-video-mach64                                   6.9.5-1build3                                      amd64        X.Org X server -- ATI Mach64 display driver
ii  xserver-xorg-video-neomagic                                 1:1.2.9-1build3                                    amd64        X.Org X server -- Neomagic display driver
ii  xserver-xorg-video-nouveau                                  1:1.0.15-2                                         amd64        X.Org X server -- Nouveau display driver
ii  xserver-xorg-video-openchrome                               1:0.6.0-3                                          amd64        X.Org X server -- OpenChrome display driver
ii  xserver-xorg-video-qxl                                      0.1.5-2build1                                      amd64        X.Org X server -- QXL display driver
ii  xserver-xorg-video-r128                                     6.10.2-1build1                                     amd64        X.Org X server -- ATI r128 display driver
ii  xserver-xorg-video-radeon                                   1:18.0.1-1                                         amd64        X.Org X server -- AMD/ATI Radeon display driver
ii  xserver-xorg-video-savage                                   1:2.3.9-1ubuntu1                                   amd64        X.Org X server -- Savage display driver
ii  xserver-xorg-video-siliconmotion                            1:1.7.9-2ubuntu1                                   amd64        X.Org X server -- SiliconMotion display driver
ii  xserver-xorg-video-sisusb                                   1:0.9.7-1build1                                    amd64        X.Org X server -- SiS USB display driver
ii  xserver-xorg-video-tdfx                                     1:1.4.7-1build1                                    amd64        X.Org X server -- tdfx display driver
ii  xserver-xorg-video-trident                                  1:1.3.8-1build1                                    amd64        X.Org X server -- Trident display driver
ii  xserver-xorg-video-vesa                                     1:2.3.4-1build3                                    amd64        X.Org X server -- VESA display driver
ii  xserver-xorg-video-vmware                                   1:13.2.1-1build1                                   amd64        X.Org X server -- VMware display driver
  • How about using Ubuntu kernels. UKUU kernels are not officially supported and may cause problems like this.
    – Pilot6
    Dec 8, 2019 at 22:41
  • There are two things. One, some hdmi cables are not compatible with all devices so it may be the cable. Two, I know it sound silly but did you unplug the cable and plug it back in? I had a toshiba laptop and faced the same problem. However, when I unplugged the cable from the laptop and then plugged it back in, the system would recognize it.
    – mchid
    Dec 8, 2019 at 23:32
  • @Pilot6 Just to be sure, I have reverted to kernel 4.18.20 (the 4.18 branch is the one for Ubuntu 18.04.2 as I understand) by installing the deb files from kernel.ubuntu.com
    – Thomas
    Dec 9, 2019 at 18:02
  • 1
    @mchid I will try to find another hdmi cable to test this and will let you know here. I did unplug and plug back the cable of course
    – Thomas
    Dec 9, 2019 at 18:03
  • No, Ubuntu kernels are not the same as mainline kernels.
    – Pilot6
    Dec 9, 2019 at 18:03

1 Answer 1


Can you provide more information about your toshiba laptop? In particular, does it have a separate graphics card? According to a web search I did, this is highly likely. For future reference, this sort of information is very important if you want help with a graphics problem.

If it does, the external ports will be connected to the graphics card, except for the VGA port. I had a Thinkpad of this vintage, same setup.

This seems the most likely explanation for your problem, since it would otherwise be very odd for external displays not to be detected. I am not completely confident about this, though, because even without the nvidia drivers, the open source nouveau drivers should have worked.

In this case, you can try the 'additional drivers' control panel. Ubuntu should detect your card, and offer to install the legacy Nvidia drivers. It will need to be legacy drivers.

Note: The kernel you are using is unlikely to cause the problem, but it is adventurous to use such a kernel. A slightly less risky approach is to use the hwe-edge kernel from the kernels proposed PPA, which is at least an official ubuntu kernel. It's 5.3 The std kernel with 18.04.3 is v5. Your machine is quite old and there is not going to be much hardware advantage in using the latest kernels. Using an officially supported kernel on LTS ubuntu will eliminate one variable.

  • There is no other card than the Intel Integrated HD Graphics one (I updated my post above with also the output from lspci). I did revert back to Ubuntu kernel 4.15
    – Thomas
    Dec 9, 2019 at 18:24
  • well, it's weird. Does your personal laptop have windows, to test that. Does your BIOS have the option of turning off an internal nvidia card, if one was present? My 2011 laptop had a bios option to turn off the nvidia card completely (in which case, lspci could not see it). Dec 10, 2019 at 10:19

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