Comment 12 for bug 1878421

from journal log this looks wrong:

Mai 14 12:12:04 frank-G5-U20 /usr/lib/gdm3/gdm-x-session[1526]: xf86EnableIOPort
s: failed to set IOPL for I/O (Operation not permitted)
Mai 14 12:12:04 frank-G5-U20 /usr/lib/gdm3/gdm-x-session[1526]: (II) modeset(0):
 using drv /dev/dri/card0
Mai 14 12:12:04 frank-G5-U20 /usr/lib/gdm3/gdm-x-session[1526]: (WW) Falling bac
k to old probe method for fbdev
Mai 14 12:12:04 frank-G5-U20 /usr/lib/gdm3/gdm-x-session[1526]: (II) Loading sub
 module "fbdevhw"
Mai 14 12:12:04 frank-G5-U20 /usr/lib/gdm3/gdm-x-session[1526]: (II) LoadModule:
 "fbdevhw"
Mai 14 12:12:04 frank-G5-U20 /usr/lib/gdm3/gdm-x-session[1526]: (II) Loading /usr/lib/xorg/modules/libfbdevhw.so

...
Mai 14 12:12:04 frank-G5-U20 /usr/lib/gdm3/gdm-x-session[1526]: (EE) open /dev/f
b0: Permission denied
Mai 14 12:12:04 frank-G5-U20 /usr/lib/gdm3/gdm-x-session[1526]: (II) modeset(G0)
: using drv /dev/dri/card1
Mai 14 12:12:04 frank-G5-U20 /usr/lib/gdm3/gdm-x-session[1526]: (WW) VGA arbiter
: cannot open kernel arbiter, no multi-card support
...
Mai 14 12:12:05 frank-G5-U20 /usr/lib/gdm3/gdm-x-session[1526]: (EE) modeset(G0): glamor initialization failed

but here it looks like monitor is correctly found (like in gnome-preferences)

Mai 14 12:12:05 frank-G5-U20 /usr/lib/gdm3/gdm-x-session[1526]: (II) modeset(G0)
: EDID for output HDMI-1-2
Mai 14 12:12:05 frank-G5-U20 /usr/lib/gdm3/gdm-x-session[1526]: (II) modeset(G0)
: Manufacturer: HPN Model: 363a Serial#: 16843009
Mai 14 12:12:05 frank-G5-U20 /usr/lib/gdm3/gdm-x-session[1526]: (II) modeset(G0)
: Year: 2019 Week: 41
Mai 14 12:12:05 frank-G5-U20 /usr/lib/gdm3/gdm-x-session[1526]: (II) modeset(G0)
: EDID Version: 1.3
Mai 14 12:12:05 frank-G5-U20 /usr/lib/gdm3/gdm-x-session[1526]: (II) modeset(G0)
: Digital Display Input