[aklug] Video out to BNC port?

James Zuelow e5z8652 at zuelow.net
Sat Dec 2 12:03:18 AKST 2017

I don't think it's permissions to the port.

I was playing around, and discovered that the TV1 port is live if there 
is a device on the other end when the system boots.  If I connect a 
cable to the BNC port after boot, I can't find a way of activating the port.

So I have a BNC->RCA adapter on the port, and then an RCA video cable to 
the composite video-in port on an overhead projector.

This solution works great!  Almost.  I could see the boot messages on 
the projector, until the framebuffer kicked in.  At that point I was 
still getting video, but it was an unreadable mess.

So easy fix, edit /etc/default/grub and add 'nomodeset' to the kernel 
boot options.  Now I can reliably put console sessions out the BNC 
port.  (aaxine anyone?)

Unfortunately xorg says "no screens found" and errors out when it 
attempts to start in automatic mode.  I have not been able to find the 
magic combination to get X and the browser to display correctly.

And xorg's "automatic" mode has been working so well for me for so many 
years that I've completely forgotten all the nuances in setting up an 
xorg.config file. I wish there was a way of running xrandr when X itself 
isn't running.  xrandr would give me some good hints on what I need.

Since this is a work project and time is important, I have plan B on the 
way.  I've got a BlackMagic Design mini monitor PCI-E card coming that I 
can put into a desktop.  BlackMagic says they have full Linux support, 
so if I can't figure it out I should have an 800 number to call.



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