Sometimes when I attach an second LCD monitor (iiyama ProLite E2407HDSV)


Native resolution   Full HD 1080p, 1920 x 1080 ( 2.1 megapixel)
Horizontal sync 30-81 KHz
Vertical sync 56-75 Hz

to my Asus N56J laptop

Display Specs:

15.6" IPS 1920 x 1080 ( Full HD ) 

and I try to extend my laptop monitor with the LCD I get the error:

could not set the configuration for crtc 64

After a few tries it does work and the error is gone. Also when I go to my display settings I get a transparent window, like so:

enter image description here

Also the following additional drivers are installed:

enter image description here

myuser@my-laptop:~$ xrandr:

Screen 0: minimum 8 x 8, current 3520 x 1200, maximum 16384 x 16384
eDP1 connected primary 1920x1080+0+0 344mm x 194mm
   1920x1080      60.1*+   59.9  
   1680x1050      60.0     59.9  
   1600x1024      60.2  
   1400x1050      60.0  
   1280x1024      60.0  
   1440x900       59.9  
   1280x960       60.0  
   1360x768       59.8     60.0  
   1152x864       60.0  
   1024x768       60.0  
   800x600        60.3     56.2  
   640x480        59.9  
HDMI1 disconnected
VGA1 connected 1600x1200+1920+0 521mm x 293mm
   1600x1200      60.0* 
   1680x1050      60.0  
   1280x1024      75.0     60.0  
   1440x900       75.0     59.9  
   1152x864       75.0  
   1024x768       75.1     70.1     60.0  
   832x624        74.6  
   800x600        72.2     75.0     60.3     56.2  
   640x480        75.0     72.8     66.7     60.0  
   720x400        70.1  
VIRTUAL1 disconnected

myuser@my-laptop:~$ sudo lshw -c video:

[sudo] password for myuser: 
       description: 3D controller
       product: GM108M [GeForce 840M]
       vendor: NVIDIA Corporation
       physical id: 0
       bus info: pci@0000:03:00.0
       version: a2
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress bus_master cap_list rom
       configuration: driver=nvidia latency=0
       resources: irq:42 memory:f6000000-f6ffffff memory:e0000000-efffffff memory:f0000000-f1ffffff ioport:e000(size=128) memory:f7000000-f707ffff
       description: VGA compatible controller
       product: 4th Gen Core Processor Integrated Graphics Controller
       vendor: Intel Corporation
       physical id: 2
       bus info: pci@0000:00:02.0
       version: 06
       width: 64 bits
       clock: 33MHz
       capabilities: msi pm vga_controller bus_master cap_list rom
       configuration: driver=i915 latency=0
       resources: irq:39 memory:f7400000-f77fffff memory:d0000000-dfffffff ioport:f000(size=64)

myuser@my-laptop:~$ lspci | grep VGA:

00:02.0 VGA compatible controller: Intel Corporation 4th Gen Core Processor Integrated Graphics Controller (rev 06

myuser@my-laptop:~$ uname -r:


myuser@my-laptop:~$ X -version:

X.Org X Server 1.17.1
Release Date: 2015-02-10
X Protocol Version 11, Revision 0
Build Operating System: Linux 3.19.0-28-generic x86_64 Ubuntu
Current Operating System: Linux mva-laptop 3.19.0-30-generic #33-Ubuntu SMP Mon Sep 21 20:58:04 UTC 2015 x86_64
Kernel command line: BOOT_IMAGE=/boot/vmlinuz-3.19.0-30-generic root=UUID=a1d7434a-6c0f-4117-8d2f-1e32f902475f ro quiet splash
Build Date: 11 September 2015  10:30:58AM
xorg-server 2:1.17.1-0ubuntu3.1 (For technical support please see http://www.ubuntu.com/support) 
Current version of pixman: 0.32.6
    Before reporting problems, check http://wiki.x.org
    to make sure that you have the latest version.

2 Answers 2


Based on the specifications for your external screen, I recommend that you change the settings to match it's native resolution. Based on your xrandr output you've got it configured for 1600x1200 @ 60 Hz One of the things the manufacturer suggests doing (in the manual) before contacting the iiyama information line is to check "if the correct native resolution has been selected via 'Display Properties".

To set things up to use the manufacturers recommended resolution you would generate a modeline with cvt. Since this is a TFT display and I can't find any indication to the contrary I'm using a refresh rate of 60 to generate the modeline.

So you'd generate the modeline with:

cvt 1920 1080 60 Which results in output similar to this:

1920x1080 59.96 Hz (CVT 2.07M9) hsync: 67.16 kHz; pclk: 173.00 MHz
Modeline "1920x1080_60.00"  173.00  1920 2048 2248 2576  1080 1083 1088 1120 -hsync +vsync

Then you would apply the modeline with xrandr with:

xrandr --newmode Everything After Modeline from the cvt output including the quotes and then

xrandr --addmode VGA1 1920x1080_60.00

Where VGA1 is the port your display is connected to and the remainder of the line is everything between quotes from the cvt output






How to set a custom resolution?


For me the solution was as simple as opening Driver Manager from the start menu and then picking a different driver and rebooting!

enter image description here

Both nvidia-460 and nvidia-495 produced the CRTC error message for me while nvidia-470 and nouveau worked just fine (although the nvidia is considered better). So try both "recommended" and the "open-source" driver for your system.

PS: The Driver Manager would not let me select options at first, so I needed to run:

sudo apt install packagekit*

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