Xfce Forum

KitchM

Member

Registered: 2009-08-15

Posts: 304

Dual Monitors Not Working

I plugged my laptop's HDMI port out to another monitor.  When I go into the Display settings there is no other monitor option.  The second monitor flashes on the screen like it is trying to sync up, but does nothing otherwise.  The laptop display stays stable with no change.

How do I get the second monitor to see the laptop?  (I am using the latest Debian Bullseye and Xfce.)

Thank you.

KitchM

Member

Registered: 2009-08-15

Posts: 304

Re: Dual Monitors Not Working

I should mention that I did of course try different HDMI cables, changed resolution and tried rebooting both systems.

ToZ

Administrator

From: Canada

Registered: 2011-06-02

Posts: 11,485

Re: Dual Monitors Not Working

Are you sure your system is recognizing the monitor?
What does "xrandr" say when it's plugged in? Also look at your logs (journal if systemd) while plugging it in.

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KitchM

Member

Registered: 2009-08-15

Posts: 304

Re: Dual Monitors Not Working

It says "Failed to get size of gamma for output default".  There are other items and the current size has an asterisk by it and is correct.  I will attempt to check the log.

KitchM

Member

Registered: 2009-08-15

Posts: 304

Re: Dual Monitors Not Working

Xorg.o.log does not show anything happening.

ToZ

Administrator

From: Canada

Registered: 2011-06-02

Posts: 11,485

Re: Dual Monitors Not Working

It says "Failed to get size of gamma for output default".  There are other items and the current size has an asterisk by it and is correct

Can you post back the xrandr output?

Also, unplug the monitor then start up the settings daemon in debug mode:

XFSETTINGSD_DEBUG=1 xfsettingsd --replace --no-daemon

...hit the enter key a good 5 times after the output has stopped to leave a marker then plug in the monitor. Post back the output.

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KitchM

Member

Registered: 2009-08-15

Posts: 304

Re: Dual Monitors Not Working

xrandr: Failed to get size of gamma for output default
Screen 0: minimum 640 x 480, current 1024 x 768, maximum 1280 x 768
default connected 1024x768+0+0 0mm x 0mm
    1280x720     0.00
    1024x768     0.00*
    800x600       0.00
    1280x768     0.00

Xlib:  extension "GLX" missing on display ":0.0".
xfce4-settings(xsettings): _XSETTINGS_S0 registered on screen 0
xfce4-settings(xsettings): 31 settings changed (serial=0, len=1212)
xfce4-settings(xsettings): resource manager (xft) changed (len=116)
xfce4-settings(displays): Detected CRTC 88.
xfce4-settings(displays): Detected output 89 default.
xfce4-settings(pointers): initialized xi 2.3
xfce4-settings(keyboards): initialized xkb 1.0
xfce4-settings(keyboards): set auto repeat on
xfce4-settings(keyboards): set key repeat (delay=500, rate=50)
xfce4-settings(keyboards): don't set numlock
xfce4-settings(accessibility): AccessXKeys disabled
xfce4-settings(accessibility): stickykeys disabled
xfce4-settings(accessibility): slowkeys disabled
xfce4-settings(accessibility): bouncekeys disabled
xfce4-settings(accessibility): mousekeys disabled

(xfsettingsd:1306): GLib-CRITICAL **: 14:41:29.806: g_str_has_prefix: assertion 'prefix != NULL' failed

(xfsettingsd:1306): GLib-GObject-CRITICAL **: 14:41:29.824: g_value_get_string: assertion 'G_VALUE_HOLDS_STRING (value)' failed

(xfsettingsd:1306): GLib-GObject-CRITICAL **: 14:41:29.844: g_value_get_string: assertion 'G_VALUE_HOLDS_STRING (value)' failed

(xfsettingsd:1306): GLib-GObject-CRITICAL **: 14:41:29.903: g_value_get_string: assertion 'G_VALUE_HOLDS_STRING (value)' failed
xfce4-settings(keyboard-shortcuts): 20 shortcuts loaded
Failed to connect to session manager: Failed to connect to the session manager: SESSION_MANAGER environment variable not defined
xfce4-settings(fontconfig): monitoring 194 paths
xfce4-settings(workspaces): 6 desktop names set from xfconf
xfce4-settings(workspaces): extended names in xfconf, waiting for property-change
xfce4-settings(workspaces): 6 desktop names set from xfconf

KitchM

Member

Registered: 2009-08-15

Posts: 304

Re: Dual Monitors Not Working

As you can see, there was nothing appearing upon plugging into the other monitor.

ToZ

Administrator

From: Canada

Registered: 2011-06-02

Posts: 11,485

Re: Dual Monitors Not Working

As you can see, there was nothing appearing upon plugging into the other monitor.

And xrandr only shows the one monitor after the second is plugged in? If so, your computer is not recognizing the second monitor (bad port?) - you'll need to address that first. Maybe keep a running:

sudo journalctl -f

...when plugging in the second monitor to see if the system recognizes it..

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KitchM

Member

Registered: 2009-08-15

Posts: 304

Re: Dual Monitors Not Working

Thanks ToZ for the help.  It appears that there is no reaction whether plugging in the HDMI cable or not.  I am beginning to think that the issue may be a firmware one.  It worked before the recent upgrade, so perhaps I need to go to Debian on this one.  Thanks again.