Bug#918457: xserver-xephyr: multi-screen setup with xinerama and RANDR extensions: extra screens not directly usable
Package: xserver-xephyr
Version: 2:1.19.2-1+deb9u5
Severity: normal
Dear Maintainer,
I'm trying to use Xephyr to test my awesome (WM) multi-screen setup.
As per instructions found on the Internet I spawned a Xephyr server with 2 screens and the Xinerama and RANDR extensions activated:
Xephyr -screen 960x540+0+0 -screen 960x540+960+0 +extension RANDR +xinerama :1 &
This spawns 2 windows side-by-side (due to the +X+Y panning information, but also works without it and has the same issue), labeled :1.0 and :1.1
However, when I ask xrandr about the screens, it sees only one screen/output
DISPLAY=:1 xrandr
xrandr: Failed to get size of gamma for output default
Screen 0: minimum 160 x 160, current 1920 x 540, maximum 1600 x 1200
default connected 960x540+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
1600x1200 0.00
1400x1050 0.00
1280x960 0.00
1280x1024 0.00
1152x864 0.00
1024x768 0.00
832x624 0.00
800x600 0.00
720x400 0.00
480x640 0.00
640x480 0.00
640x400 0.00
320x240 0.00
240x320 0.00
160x160 0.00
960x540 0.00*
So when I start awesome (WM) on this display, it detects only the first screen/output
DISPLAY=:1 awesome &
Now if I attempt to start an xterm on the first screen, it works correctly
DISPLAY=:1.0 xterm &
I can even move this terminal toward the right screen and it becomes visible on the second (:1.1) screen, so perhaps Xinerama is working.
However, If I attempt to start an xterm on the second screen directly, it fails (even without awesome)
DISPLAY=:1.1 xterm &
xterm: Xt error: Can't open display: :1.1
My feeling so far is that the second (possibly any extra) display is not properly advertised or registered. Perhaps the RANDR extension is not working properly?
Xephyr doesn't seem to output anything, I wasn't able to find any option that would make it more verbose.
-- System Information:
Debian Release: 9.6
APT prefers stable-updates
APT policy: (500, 'stable-updates'), (500, 'stable')
Architecture: amd64 (x86_64)
Foreign Architectures: i386
Kernel: Linux 4.9.0-8-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE=en_US:en (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
Versions of packages xserver-xephyr depends on:
ii libaudit1 1:2.6.7-2
ii libbsd0 0.8.3-1
ii libc6 2.24-11+deb9u3
ii libdbus-1-3 1.10.26-0+deb9u1
ii libdrm2 2.4.74-1
ii libepoxy0 1.3.1-2
ii libgcrypt20 1.7.6-2+deb9u3
ii libgl1-mesa-glx [libgl1] 13.0.6-1+b2
ii libpixman-1-0 0.34.0-1
ii libselinux1 2.6-3+b3
ii libsystemd0 232-25+deb9u6
ii libudev1 232-25+deb9u6
ii libx11-6 2:1.6.4-3+deb9u1
ii libx11-xcb1 2:1.6.4-3+deb9u1
ii libxau6 1:1.0.8-1
ii libxcb-glx0 1.12-1
ii libxcb-icccm4 0.4.1-1
ii libxcb-image0 0.4.0-1+b2
ii libxcb-keysyms1 0.4.0-1+b2
ii libxcb-randr0 1.12-1
ii libxcb-render-util0 0.3.9-1
ii libxcb-render0 1.12-1
ii libxcb-shape0 1.12-1
ii libxcb-shm0 1.12-1
ii libxcb-util0 0.3.8-3+b2
ii libxcb-xf86dri0 1.12-1
ii libxcb-xkb1 1.12-1
ii libxcb-xv0 1.12-1
ii libxcb1 1.12-1
ii libxdmcp6 1:1.1.2-3
ii libxfont2 1:2.0.1-3+deb9u1
ii libxshmfence1 1.2-1+b2
ii xserver-common 2:1.19.2-1+deb9u5
Versions of packages xserver-xephyr recommends:
ii libgl1-mesa-dri 13.0.6-1+b2
xserver-xephyr suggests no packages.
-- no debconf information
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