So I did test the setup with "CRT Emudriver & CRT Tools 2.0 beta 15
(Crimson 16.2.1 non-GCN* cards) for Windows 7/8/10 64-bits"
I just think that I should have tried this one too "CRT Emudriver & CRT Tools 2.0 beta 15
(Catalyst 12.6) for Windows 7/8/10 64-bits",
as my HD 6450 seems to be supported by both. (The Catalyst driver gives me a BSOD with "PAGE_FAULT_IN_NONPAGED_AREA" on atikmdag.sys )
Anyway, the result is very strange :
When I follow the guidelines, as soon as I enable "EDID emulation" I have a "rolling unsynced" windows 10 desktop on TV, UNTIL I push "Activate composite sync".
Then, I have no more desktop : only a black screen... but it's synced : I see it on the sony TV GUI ! (AV1 is displayed in green on the top left corner without rolling effect)
Moreover : when I change resolution with Windows10 internal tool, from 240x192 to 768x512 (or any in between) : it "works" too ! Still a blackscreen, but I see scanlines changing on Sony GUI.
For a moment I thought : maybe it's because I have 2 displays and 2 graphics card. So I stopped "extended desktop" between the LCD and the TV, and chose "TV only".
I also tried "generic 15 KHz" profile instead of "arcade 15KHz". I tried the "csync workaround" : change polarities to "1" instead" of "0" in the "base" Modeline.
Still blackscreen.
Then I thought : let's forgot windows desktop, and try to output groovymame on the TV (after modifying the screen setting in mame.ini ) : switchres seems happy, I even see the game on the "alt-tab" preview, I can interact "blindly" ... but TV stays black.
After all that I don't know what to think.
It seems Radeon HD 6450 may not be able to activate composite sync, because of its hardware.
But Windows and Linux "misbehave" in different ways, and Windows "CRT Emudriver" seems *so close* to work.