0
Not a bug

Headless Linux Black Screen

Craig Kibodeaux 3 years ago updated by Eric Davis 2 years ago 7

Trying the new headless Linux feature, and maybe I'm doing something wrong, but when I connect to the client all I receive is a black screen.

ConnectWise Control Version:
1
Server Affected:
Host Client Affected:
Guest Client Affected:

Answer

Answer
Not a bug

The current client screen capturer only supports 32-bit and 1-bit framebuffers. You can head over to the Feature Request forum to propose or vote for additional bit depth support.

Waiting for information

Good morning,


We're currently investigating a few reports of hosts being presented with a black screen upon connection to headless Linux guest machines, in particular, headless Linux guest machines hosted in AWS (regardless of Linux distro).


If you can, please run our Linux framebuffer diagnostic script on one of the machines on which you're seeing a black screen and update this thread with the output. The script, getLinuxFrameBufferDetails.sh, is available to download from the following KB article:


https://docs.connectwise.com/ConnectWise_Control_Documentation/Get_started/Knowledge_base/Connect_to_a_headless_Linux_machine


Also, please provide more detailed information about the affected Linux guest(s): distro, hosting environment (AWS, GCP, vmware, etc.), client version, and so on.


Regards,

Ben

Server: Ubuntu Server 16.04 LTS - Hosted on Digital Ocean
Host: XUbuntu Desktop 17.10 - Bare Metal
Client: Ubuntu Server 16.04 LTS - Bare Metal


All machines are 64-bit and up to date. Using openjdk-8. ConnectWise Control version 6.4.15083.6507 on all.


sudo ./getLinuxFrameBufferDetails.sh 

[sudo] password for ckibodeaux: 
------------------------------------------------------
Details for Frame Buffer /dev/fb0: 
Width : 1024
Height : 768
Stride : 1024
Bits Per Pixel : 8
Red Offset : 0
Green Offset : 0
Blue Offset : 0
Red Length : 8
Green Length : 8
Blue Length : 8
------------------------------------------------------


I have a raspberry Pi i am trying to conenct to.  I can get the installer to work and it shows up in the access area but when i connect all i get is black screen. 


Details for Frame Buffer /dev/fb0:
Width : 1920
Height : 1080
Stride : 7680
Bits Per Pixel : 32
Red Offset : 16
Green Offset : 8
Blue Offset : 0
Red Length : 8
Green Length : 8
Blue Length : 8


While we don't support installations of the Control client on Pi devices, you might be running the default and/or an older version of Java, which is preventing the client from interrogating/processing the framebuffer.


What version of Java's installed on the Pi?


Also, does /var/log/screenconnect-xxxxxxxxxxxxxxxx log any exceptions (replace the x's with your server's public thumbprint)?


Cheers,

Ben

Installed access client on bare metal Ubuntu 18.04.1 LTS and client shows up on dashboard. When joining the session you can only see a black screen, however keyboard input is being transmitted.


Using openjdk-8 for the host and CW Control version 6.8.20124.6845.

Details for Frame Buffer /dev/fb0:
Width : 1024
Height : 768
Stride : 2048
Bits Per Pixel : 16
Red Offset : 11
Green Offset : 5
Blue Offset : 0
Red Length : 5
Green Length : 6
Blue Length : 5

Error in /var/log/screenconnect-xxx keeps repeating forever when connected to client.

2018-10-19 10:08:56.044 -0500 Exception:
java.lang.IllegalArgumentException
at com.screenconnect.client.ClientScreenCapturer$FrameBufferMonitorManager.captureMonitor(ClientScreenCapturer.java:154)
at com.screenconnect.IncrementalScreenCapturer.run(IncrementalScreenCapturer.java:100)
at com.screenconnect.ScreenCapturer.run(ScreenCapturer.java:59)
at com.screenconnect.CaptureThreadRunner.run(CaptureThreadRunner.java:38)
at com.screenconnect.ThreadRunner.runThread(ThreadRunner.java:74)
at com.screenconnect.ThreadRunner.access$000(ThreadRunner.java:5)
at com.screenconnect.ThreadRunner$1.run(ThreadRunner.java:42)
at java.lang.Thread.run(Thread.java:748)

Experiencing the same issue with a Ubuntu 16/04  LTS on hyper-v 

Details for Frame Buffer /dev/fb0:
Width : 1152
Height : 864
Stride : 2304
Bits Per Pixel : 16
Red Offset : 11
Green Offset : 5
Blue Offset : 0
Red Length : 5
Green Length : 6
Blue Length : 5

2019-01-02 16:52:48.647 +0000 Exception:
java.lang.IllegalArgumentException
at com.screenconnect.client.ClientScreenCapturer$FrameBufferMonitorManager.captureMonitor(ClientScreenCapturer.java:154)
at com.screenconnect.IncrementalScreenCapturer.run(IncrementalScreenCapturer.java:100)
at com.screenconnect.ScreenCapturer.run(ScreenCapturer.java:59)
at com.screenconnect.CaptureThreadRunner.run(CaptureThreadRunner.java:38)
at com.screenconnect.ThreadRunner.runThread(ThreadRunner.java:74)
at com.screenconnect.ThreadRunner.access$000(ThreadRunner.java:5)
at com.screenconnect.ThreadRunner$1.run(ThreadRunner.java:42)
at java.lang.Thread.run(java.base@9-internal/Thread.java:804)

Answer
Not a bug

The current client screen capturer only supports 32-bit and 1-bit framebuffers. You can head over to the Feature Request forum to propose or vote for additional bit depth support.

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