[arm-allstar] HDMI and the PI

[Ken]

Thanks for the info.  I ended up using-
gpu_mem=64
hdmi_force_hotplug=1
hdmi_drive=2
hdmi_group=1
hdmi_mode=4

with just the force hotplug, the resolution of the display was quite low -
although it did achieve the objective of letting me connect the monitor to
an already-running pi and having it actually work. 

There are a lot of modes you can choose from, as explained in the raspberry
pi site:
https://www.raspberrypi.org/documentation/configuration/config-txt/video.md

I just picked 720P as something that any generic/cheap HDMI monitor ought to
be able to do.
I will probably put this on every one of my RPI's. 

Thanks!
Ken
KE2N