Detecting builtin displays

Hello,

First of all, my apologies if this has been discussed before - I nor google could find

any prior postings. This is also my first post to this list, so please let me know if there's

a more appropriate list to be posting on.

I've been looking at why gnome-settings-daemon always has an inhibitor lock for

"Multiple displays attached".

It seems in libgnome-desktop/gnome_rr.c:_gnome_rr_output_name_is_builtin_display (),

a builtin display is determined by RANDR output names, namely "lvds", "LVDS", "Lvds",

"LCD", and "eDP".

I have a laptop (Dell M4800) that reports its output for the builtin display as "DP-4",

and thus always gets reported as having a builtin display attached, leading to the inhibitor

lock being set for multiple displays attached at all times.

I noticed that output of "xrandr --properties" shows a "ConnectorType" that has a value

"Panel" instead of "DisplayPort" for my builtin display named "DP-4".

Would that be a possibly better way to help determine what is a builtin display instead of

relying upon the RANDR output name alone?

I'm not looking to propose any changes, rather I have a few models of Dell laptops

we use at my office that run into this and I was looking at maintaining some patches for this locally.

I'm wondering if anyone has any advice as to whether "ConnectorType" would be a good direction

to go in, or any ideas for a different direction to look.

Best Regards,

-Brenton