Gdm crashes if HDMI monitor connected

MNT Pocket Reform
1

When I plug a cable into the HDMI connector on my Pocket (I’ve tried a white Raspberry Pi micro-HDMI cable, as well as a generic black micro-HDMI cable I bought somewhere or other) and connect it to a monitor, gdm crashes on launch after drawing the login screen on the internal monitor.

If I have the HDMI connected at power-up, I get a brief flash of something or other just after power-on, so I believe the cable and monitor are good, and I’m just having some software issue.

I’m not quite current on software, but I was current before the most recent issue and subsequent fix. Just haven’t had the time yet.

Any ideas about what I need to do to get this working? A big monitor is a lot easier on the eyes in the evening.

2

So… page 40 of the Operator Handbook notes that “Some processor modules allow you to connect an external display on the HDMI port, but not all of them can drive both the internal and external display at the same time. If your module supports dual display, plugging in an external monitor should just work.”

So apparently the imx8mp doesn’t support two displays?

3

It does support them.