Created attachment 92080 [details]
Xorg.0.log with xf86-video-ast

xf86-video-ast seems to be better:

[    30.563] (II) AST(0): EDID (in hex):
[    30.563] (II) AST(0):     00ffffffffffff0009d10b7945540000
[    30.563] (II) AST(0):     291201030e2f1a782e3585a656489a24
[    30.563] (II) AST(0):     125054a56bba710081008140950f8180
[    30.563] (II) AST(0):     9500b3000101944380907238284080c8
[    30.563] (II) AST(0):     3500dc0c1100001e000000ff00414138
[    30.563] (II) AST(0):     31313033393032360a20000000fd0032
[    30.563] (II) AST(0):     4c1e5e15000a202020202020000000fc
[    30.563] (II) AST(0):     0042656e5120453232303048440a00f8
[    30.563] (II) AST(0): EDID vendor "BNQ", prod id 30987