Luoshuang's GPULightmass

[kouropalatisk]

@Muchasty

That dude just increased Light Map resolution to 1024 for his walls to have less blured shadow ( more pixels take shadow casting information so the shadow edge will be more defined)
If you want to have very defined shadows using HDRI you could try also tweak HDRI texture parameters such as Brightness Curve (for contrast) + Brigthness (for lightness).

Light Map res at 1024 = already did that.

HDRI
i. brightness curve set to 0.5
ii. brightness contrast set to 0.5

I also set the above to 2, still no luck