amd radeon - laptop - lvds showing nothing with hdmi+vga

[hd66]

hello

i dont know if it's normal but..

running free amd driver or proprietary driver, LMDE can't show on all three screens on laptop :
both vga + hdmi plugged are working wel, but then lvde just shows blank screen, from the moments both external screen are plugs, until computer is powered off.

just tried with windows, all three works well at the same time.. why?
xorg.0.log
dmesg
lspci
are in the attached archive (form refused to accept "original filenames or sizes")

thank you!
ver hard to attach simple texts files btw, too large or invalid extension.