Comment # 15 on bug 1191515 from Stefan Dirsch

--- working
--- black screen on HDMI monitor
[...]
- (II) modeset(G0): glamor X acceleration enabled on NV167
- (II) modeset(G0): glamor initialized
- (II) modeset(G0): Output HDMI-1-1 has no monitor section
- (II) modeset(G0): EDID for output HDMI-1-1
+ (II) modeset(G0): Refusing to try glamor on llvmpipe
+ (EE) modeset(G0): glamor initialization failed
+ (II) modeset(G0): ShadowFB: preferred YES, enabled YES
+ (II) modeset(G0): Double-buffered shadow updates: off
+ (II) modeset(G0): Output HDMI-1-2 has no monitor section
+ (II) modeset(G0): EDID for output HDMI-1-2
[...]
+ (II) Loading sub module "shadow"
+ (II) LoadModule: "shadow"
+ (II) Loading /usr/lib64/xorg/modules/libshadow.so
+ (II) Module shadow: vendor="X.Org Foundation"
+       compiled for 1.20.13, module version = 1.1.0
+       ABI class: X.Org ANSI C Emulation, version 0.4
[...]
- Setup complete
-   DRI driver: nouveau
-   VDPAU driver: nouveau
[...]
- randr: falling back to unsynchronized pixmap sharing
- (II) modeset(G0): Allocate new frame buffer 1920x1080 stride

That would mean that before nouveau driver was being used for 2D acceleration
for some reason. This makes no sense to me.
Your xrandr output looks good. No idea, why the screen stays black.