Monitor DisplayPort loses image after login

R

rmomota

I just got a new DisplayPort cable, was using VGA before, and the system seems alright until login.

When booting with laptop lid closed the monitor shows all boot process even launches LightDM login, working perfectly normal.
Then I insert user and password to login in a XFCE session it still shows the desktop for a second and then gets blank until the monitor goes to sleep.

When trying to configure dual screen the monitor gets detected but never shows image.
I've no xorg configuration for displays as I'm letting the system detection work.

The cable is new and it works perfectly fine until login just as explained before.

With VGA cable in the same monitor I've got no problem at all.
Is there any specific configuration missing for DisplayPorts?
 
I guess that when you entering your session that an configuration is applied which is not compatible with the monitor.

What if you clear out the settings from XFCE?

Also like to share the Xorg log file?
 
rmomota said:
With VGA cable in the same monitor I've got no problem at all.
Is there any specific configuration missing for DisplayPorts?
Click to expand...
The laptop has Displayport and VGA output to the external monitor and previously you used VGA to the monitor instead of Displayport, is that correct?
If the external monitor has multiple inputs, you should be able to cycle through them via buttons/on screen menu on the monitor itself. Perhaps it's not detecting signals from the correct input.

Typically the displayport and vga will show as different xrandr devices; not sure of the exact commands but try:
xrandr --listmonitors
xrandr --listproviders
xrandr -q

to list the possible configurations. Do the commands with the cable in the displayport and in the vga port

www.maketecheasier.com

How to Setup Dual Monitors With XRandR - Make Tech Easier

If you've ever found yourself stumped by resolution issues in Linux, XRandR and ARandR might just be the tools you need to solve your issues.
www.maketecheasier.com www.maketecheasier.com
 
mer said:
If the external monitor has multiple inputs, you should be able to cycle through them via buttons/on screen menu on the monitor itself
Click to expand...
Yes but I can't cycle because it's not detecting any input and with only one active input it detects and switches automatically.

xrandr --listmonitors
Monitors: 2
0: +eDP-1 1366/309x768/174+0+0 eDP-1
1: +DP-1 1920/476x1080/267+1366+0 DP-1

xrandr --listproviders
Providers: number : 1
Provider 0: id: 0x46 cap: 0xb, Source Output, Sink Output, Sink Offload crtcs: 3 outputs: 5 associated providers: 0 name:Intel
 
Trying the same but with Manjaro Linux (different laptop also Intel GPU) and it works
xrandr --listmonitors
Monitors: 2
0: +*LVDS-1 1366/309x768/173+0+312 LVDS-1
1: +DP-3 1920/476x1080/267+1366+0 DP-3

xrandr --listproviders
Providers: number : 1
Provider 0: id: 0x49 cap: 0xf, Source Output, Sink Output, Source Offload, Sink Offload crtcs: 3 outputs: 8 associated providers: 0 name:modesetting

I see some differences here, that LVDS-1 of laptop monitor, in FreeBSD is identified as eDP
and also +DP-3 is identified as +DP-1
I have no idea of what this means.

But I can conclude that there's no problem with the cable nor the monitor.

The Xorg log detects
[ 52.084] (II) intel(0): Output eDP-1 using initial mode 1366x768 +0+0
[ 52.084] (II) intel(0): Output DP-1 using initial mode 1920x1080 +1366+0

ps aux | grep X
... /usr/local/libexec/Xorg :0 -seat seat0 -auth /var/run/lightdm/root/:0 -nolisten tcp vt9 -novtswitch

I really wonder what happens after login that causes the monitor to turn off as it seems no data is sent to DP-1.
 
I QUIT!!!!
It's surely a XFCE4 problem or some other component that gets triggered with session login and impossible to fix without a source code fix.

Both displays work on LightDM and DP turns off when XFCE4 gets launched despite it's detected in all tools, the system gives extended desktop space as it's was On but the screen remains Off.

I'm going back to VGA.

Thanks anyway.
 
You must log in or register to reply here.
Back
Top