It seems both answers are correct, depending on where you look:
$ edid-decode /sys/class/drm/card0-HDMI-A-1/edid ... Maximum image size: 52 cm x 33 cm ... Detailed mode: Clock 154.000 MHz, 519 mm x 324 mm
Though I suggest we should be using the latter.
It seems both answers are correct, depending on where you look:
$ edid-decode /sys/class/ drm/card0- HDMI-A- 1/edid
...
Maximum image size: 52 cm x 33 cm
...
Detailed mode: Clock 154.000 MHz, 519 mm x 324 mm
Though I suggest we should be using the latter.