pi4 setup multiple displays as extended


trying to setup dual monitors on raspberry pi4 as extended., Currently it displays as mirrored. Quite new to manjaro OS (arm)., need help in display settings and config.


This is a copy and paste from another thread I responded to here in another thread:

I am seeing the same here with my messed up monitor situation.

I read that the RPi people re-wrote their Screen configuration utility for the pi4 but every screen shot I saw of the utility just showed 2 screen icons but there was no screen shot of anything in it's menus. Also every picture I saw the monitors were mirrored.

The only way I see if expanded is possible is to load up the raspian image with their screen utility and go through the menu's to see if there is way to enable expand.

If that is possible to expand then that presents another issue as currently our desktop environment does not see but one monitor. There will have to be some code re-written for the p4 or some how some one ports over the RPi screen utility or write an equivalent program. If the RPi screen utility uses any libs under /opt/vc then all bets will be off of porting it as it has 32 bit libs and no one as of yet I know has been able to port those lib/headers over to use 64bit and the pi people have no interest in doing so up to now so /opt/vc directory does not exist on 64 bit images.

After more thought it might be possible to set up configs for both monitors in xorg.conf. Possibly if both monitors are recognized by xorg and show up in the Manjaro image Display utility then might be able to set the monitors to be expanded.

Hi Darksky
Thank you for the reply., Below is the screenshot of the desktop display. All of the settings below are as default and can not be changed.

These are screenshots of additional settings. Both of the screens are connected but are showing as one Default.

More display config settings from xfconf file.

Yep. That is what I am seeing here also. Like I said above maybe manually defining the 2 monitors in xorg.conf file then xorg might pick up both monitors and then both monitors will show up in the utility.

I do not use 2 monitors but have messed with them in the past as with different types of virtual desktops and in the end I just not have much use for them.

cool., fairly new in this space, do you know which one do i have to modify.

xorg.conf will not be there. Have to make one and create a monitor a section in it.

It has been many years since I had to mess with one so I am as rusty as can be on it. It would require a lot of research for me.

Unless any one here has had any experience with it, do a search for dual monitors in xorg.config. The xorg.conf file disappeared many years ago and is only used for problem monitor situations now.

Probably the best bet is start a thread on the raspberry pi forum but they might not be willing to help much since you are running manjaro. I would be upfront with that part and say the pi4 is not recognizing your monitors edid.

Will this put a smile on your face?

I am in v3d mode and it will show the default xfce wallpaper on my second monitor as Strit mentioned in another post using V3D and have not changed it yet. It also shows my second monitor as being 7" which is incorrect but who cares as long as 2 monitors shows up and have extended desktop.

Second tab of the Screen utility:

What I discovered was I had to use hdmi_group=1 and it's hdmi_mode=16 (1080p 60Hz) (instead of hdmi_group=2) with my VIZIO tv because of it's EDID issues in config.txt. I did not have to define anything for the Gateway monitor as the edid info was getting aquired from it. I also added hdmi_force_mode=1 to force the hdmi_mode & hdmi_drive specs for my VIZIO.


Hi Darksky ..As i was almost about to give up.. this is super surely a great start to the morning..., just trying to digest all this info in and will give this another shot. :grin:

I have an unproven theory here is that if one had 2 identical monitors and both were supplying the correct EDID info to the pi4 then there might not be the issue we have been having. I think if 2 monitors are connected and only 1 (or both) not providing the correct EDID info it puts the pi4 in a tailspin so to speak. I did not have to do any special config for my Gateway monitor but did for my VIZIO. It is also interesting that manually specifying hdmi_group 2 did not work and had to use hdmi_group 1 and it's hdmi_mode.

Hey Darksky, I've been out on a business trip and could not reply. I am on a flight as I type. I used the Rpi Raspbian image and looked at the config file. It is all hashed out, but has some good info. My problem has persisted with my monitors remaining mirrored. Raspbian displayed both monitors expanded upon boot, so I am not sure where it is called in the boot process. I have two matching Samsun curved 27" monitors. And their EDIDs are communicated properly. When I get back, I will try a different branded monitor for the second screen. I am curious if both monitors having the same EDID is tripping something. I can't imagine why it would. I tried looking for the xorg, but it was not in the Raspbian image. I will update if I can figure something out, unless someone gets to it first.

I am also seeing this issue with my Pi4 4gb... the install is flawless any everything works well, but running dual monitors the image is mirrored instead of spanned.

The two monitors I am running are identical models, so perhaps there is an issue with using two monitors with the same EDID?

I'm hoping someone else has found a solution as I'm all out of thoughts.


What is your monitor's resolution and refresh rate?

I have also the same problem with the same monitors and with different ones. It mirrors only one screen and not extend it in both. I tried to follow your instructions for config. txt with blocking EDID, but it shows only one display with the name default.

Everything else in the installation works well.

I will really appreciate a solution, thanks

Post you config.txt you used and also give the screen resolutions and refresh rates of each.

1080p @ 60hz... they're LG panels.

I've also tried with different monitors and experience the same problems.

I will try and post config details soon, thanks for the help!

Did you try this:

#First HDMI port
#Second HDMI port

Also make sure you have these settings in the Screen Settings:

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