lordaker
Posts: 30
Joined: Wed Sep 20, 2017 8:31 am

Re: Dual Monitors

Wed Jan 10, 2018 1:56 pm

This is my xorg.conf

Code: Select all

Section "Device"
# RPI HDMI Monitor, framebuffer 0
	Identifier "rpi"
	Driver "fbdev"
	Option "fbdev" "/dev/fb1"
	Option "ShadowFB" "off"
EndSection

Section "Device"
# USB DisplayLink Adapter Video, framebuffer 1
	Identifier "uga"
	Driver "fbdev"
	Option "fbdev" "/dev/fb0"
	Option "ShadowFB" "off"
EndSection

Section "Monitor"
	Identifier "Philips"
EndSection

Section "Monitor"
	Identifier "Philips"
EndSection

Section "Screen"
	Identifier "primary"
	Device "rpi"
	Monitor "Philips"
EndSection

Section "Screen"
Identifier "secondary"
Device "uga"
Monitor "Philips"
EndSection

Section "ServerLayout"
Identifier "default"
Screen 0 "primary" 0 0
Screen 1 "secondary" LeftOf "primary"
EndSection

Somebody can help me ?

Justin Buist
Posts: 8
Joined: Thu Jan 18, 2018 10:43 pm

Re: Dual Monitors

Thu Jan 18, 2018 10:48 pm

I'm working on something very close to your setup lordaker. Here's my xorg.conf file:

Code: Select all

Section "Device"
        Identifier "onboard"
        Driver "fbturbo"
        Option "fbdev" "/dev/fb0"
        Option "ShadowFB" "off"
EndSection

Section "Device"
        Identifier "displaylink"
        Driver "fbturbo"
        Option "fbdev" "/dev/fb1"
        Option "ShadowFB" "off"
EndSection

Section "Monitor"
        Identifier "pihdmi"
EndSection

Section "Monitor"
        Identifier "customer"
EndSection

Section "Screen"
        Identifier "screen0"
        Device "onboard"
        Monitor "pihdmi"
        DefaultDepth 16
        SubSection "Display"
                Depth 16
                Modes "1024x728"
        EndSubSection
EndSection

Section "Screen"
        Identifier "screen1"
        Device "displaylink"
        Monitor "customer"
        DefaultDepth 16
        SubSection "Display"
                Depth 16
                Modes "1024x768_60.0"
        EndSubSection
EndSection

Section "ServerLayout"
        Identifier "Default"
        Screen 0 "screen0" 0 0
        Screen 1 "screen1" RightOf "screen0"
        Option  "Xinerama" "true"
EndSection
It's kind of working but there's some quirks. Notice the Mode line in the first monitor -- 1024x728 not 1024x768. While the monitor only works in 1024x768 mode accidentally trying 1024x728 helped. When X fires up my second monitor (/dev/fb1) lights right up but at the wrong resolution. It's at 1920x1080. The primary monitor (/dev/fb0, onboard) is totally black. If I hop to a tty (ctrl+alt+f2) and login, set DISPLAY=:0 and then launch 'arander' and hop back to vt7 (alt+f7) NOW my primary screen comes up. There's no arandr program on the screen though and I don't know why.

I suspect I need to tweak refresh rates on the monitor to get the two to function at the same time upon first boot. If I figure it out I'll post the final answer.

The setup I've got is a Pi3 running Raspbian Stretch, xserver-xorg-fbturbo package installed, using a DisplayLinkn 165 USB 2.0 dongle for the second monitor.

lordaker
Posts: 30
Joined: Wed Sep 20, 2017 8:31 am

Re: Dual Monitors

Thu Feb 01, 2018 9:36 am

In the section of your xorg.conf where you put this one:

Code: Select all

Section "Screen"
        Identifier "screen1"
        Device "displaylink"
        Monitor "customer"
        DefaultDepth 16
        SubSection "Display"
                Depth 16
                Modes "1024x768_60.0"
        EndSubSection
EndSection
If I made same thing with my monitors, I will solve my problem of display ?
My resolution screen for two monitors Philips Brilliance 220sw is 1680x1050. I will try with the configuration of your xorg.conf;
Because I don't use the subsection in xorg.conf @Justin Buist. Let me see that and I'll comeback with the result that I have.

rwolenski
Posts: 1
Joined: Fri Apr 27, 2018 9:24 pm

Re: Dual Monitors

Fri Apr 27, 2018 9:32 pm

I have a Doublesight USB monitor that I have hooked up and just set mine up with

Code: Select all

################## Device Definitions  #########
#########
######### Dual Monitors ############
Section "Device" 
  Identifier "uga"
  Driver "fbdev"
  Option "fbdev" "/dev/fb1"
  Option "ShadowFB" "off"
EndSection

Section "Device"
  Identifier "RPi_HDMI"
  Driver "fbdev"
  Option "fbdev" "/dev/fb0"
  Option "ShadowFB" "off"
EndSection

################ Monitor Definitions ###########

Section "Monitor"
  Identifier "USBMonitor"
  VendorName "DoubleSight"
  ModelName "DS-70U"
EndSection

Section "Monitor"
  Identifier "HDMI_Monitor"
  VendorName "Standard HDMI"
#  Option "DPMS"
EndSection

############## Screen Definitions #############

Section "Screen"
  Identifier "USBScreen"
  Device "uga"
  Monitor "USBMonitor"
  SubSection "Display"
    Modes "800x480"
  EndSubsection
EndSection

Section "Screen"
  Identifier "Main"
  Device "RPi_HDMI"
  Monitor "HDMI_Monitor"
EndSection

################ Actual Layout ################

Section "ServerLayout"
  Identifier "default"
  Screen 1 "Main" 0 0
  Screen 0 "USBScreen"
EndSection
I have both monitors come up, however only I can only access the USB monitor, can't get to the HDMI monitor. It's there, the desktop and background shows up with no menu bar, but I can't access it. Any ideas?

Justin Buist
Posts: 8
Joined: Thu Jan 18, 2018 10:43 pm

Re: Dual Monitors

Wed Jun 06, 2018 7:32 pm

Finally got it! I put my dual-head project on hold for a few months and just came back to it today with a fresh head.

The board is a 3b+ and the USB dongle is a DisplayLink 165 chip. Base system is Raspbian squeeze up to date as of today (2018-06-06)

Here's my /etc/X11/xorg.conf (basically ripped right from this thread in an earlier post):

Code: Select all

Section "Device"
    Identifier "displaylink"
    Driver "fbturbo"
    Option "fbdev" "/dev/fb1"
    Option "ShadowFB" "off"
EndSection

Section "Device"
    Identifier "Raspberry Pi FBDEV"
    Driver "fbturbo"
    Option "fbdev" "/dev/fb0"
    Option "ShadowFB" "off"
EndSection

Section "Monitor"
    Identifier "AOC1"
EndSection

Section "Monitor"
    Identifier "AOC2"
EndSection

Section "Screen"
    Identifier "screen"
    Device "displaylink"
    Monitor "AOC2"
EndSection

Section "Screen"
    Identifier "screen1"
    Device "Raspberry Pi FBDEV"
    Monitor "AOC1"
EndSection

Section "ServerLayout"
    Identifier "default"
    Screen 0 "screen1" 0 0
    Screen 1 "screen" RightOf "screen1"
    Option "Xinerama" "true"
EndSection
The kicker was remembering that the DisplayLink only does 16 bit color mode but trying to set my xorg.conf to force the onboard pi HDMI display to 16 bit freaked it out. I had to add this to my /boot/config.txt:

Code: Select all

framebuffer_depth=16
And that last little bit was the big trick to making it work. Xinerama won't run if your displays are different bit depths.

lordaker
Posts: 30
Joined: Wed Sep 20, 2017 8:31 am

Re: Dual Monitors

Thu Jun 07, 2018 2:46 pm

Hello @Justin Buist ,

I make an update and upgrade of my os Raspbian Stretch, Do some modification on my xorg.conf file by following yours and now is work.
But in my second screen the resolution is quick little and the icons are big. How can I change the resolution of second monitor ?

This my code via your code and parameters:

Code: Select all

Section "Device"
    Identifier "displaylink"
    Driver "fbturbo"
    Option "fbdev" "/dev/fb1"
    Option "ShadowFB" "off"
EndSection

Section "Device"
    Identifier "Raspberry Pi FBDEV"
    Driver "fbturbo"
    Option "fbdev" "/dev/fb0"
    Option "ShadowFB" "off"
EndSection

Section "Monitor"
    Identifier "PHILIPS 221E"
EndSection

Section "Monitor"
    Identifier "PHILIPS Brilliance 220SW"
EndSection

Section "Screen"
    Identifier "screen"
    Device "displaylink"
    Monitor "PHILIPS Brilliance 220SW"
EndSection

Section "Screen"
    Identifier "screen1"
    Device "Raspberry Pi FBDEV"
    Monitor "PHILIPS 221E"
EndSection

Section "ServerLayout"
    Identifier "default"
    Screen 0 "screen1" 0 0
    Screen 1 "screen" RightOf "screen1"
    Option "Xinerama" "true"
EndSection
But on my second screen "PHILIPS Brilliance 220SW", I have little resolution all my icons are big. How can I resolve that ?
I see we can install xorg-xrandr for change the resolution of the screen but I don't able to install it ?

Best regards,
Lordaker
Last edited by lordaker on Fri Jun 08, 2018 8:44 am, edited 1 time in total.

Justin Buist
Posts: 8
Joined: Thu Jan 18, 2018 10:43 pm

Re: Dual Monitors

Thu Jun 07, 2018 6:55 pm

You can set the resolution by modifying the 'Screen' section in /etc/X11/xorg.conf:

Code: Select all

Section "Screen"
        Identifier "screen"
        Device "displaylink"
        Monitor "AOC2"
        SubSection "Display"
                Modes "1920x1080"
        EndSubSection
EndSection
Note that the mode has to be supported by framebuffer so not every possible resolution seems to work. For instance I kept trying to force mine to 1024x768 which just isn't in the cards for that monitor with framebuffer support. I had to "settle" for 1920x1080 instead.

lordaker
Posts: 30
Joined: Wed Sep 20, 2017 8:31 am

Re: Dual Monitors

Fri Jun 08, 2018 9:21 am

My USB 2.0 to VGA (U2-165-VGA) DisplayLink work well. And The max resolution of my second monitor is 1680x1050 (PHILIPS Brilliance 220SW).

Code: Select all

Section "Screen"
    Identifier "screen"
    Device "displaylink"
    Monitor "PHILIPS Brilliance 220SW"
    SubSection	"Display"
    		Mode	"1680x1050"
    EndSubSection
EndSection
But I have always the same display on my second monitor.
I use a DisplayLink USB 2.0 to VGA (U2-165-VGA). I try to install xorg-xrandr but when I put the command
xrandr in my terminal emulator I have the message below:
RandR extension missing

Photo:
Image

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