I have seen some comments in this forum that GDI printers would not be expected to work, yet there are apparently some GDI printers that do work (reported in the compatible hardware threads).

So, please could someone post some advice about why GDI printers might or might not work?

(I'm assuming that one would use Oleg's software and configure the output to port as Raw. BTW, the printer I'm trying is a Panasonic KX-P6300.)

Is it anything to do with bidirectional support?
What features of GDI printers would one look at to decide whether to spend time fiddling in the hope of success, or whether there is no hope?