Recently I tested it and it worked. Now it doesn't work.

Choosing view - vr mode opens a fullscreen window, but it is completely black.

This is the complete output after clicking on vr mode:

Using breakpad crash handler
Setting breakpad minidump AppID = 250820
Forcing breakpad minidump interfaces to load
Looking up breakpad interfaces from steamclient
Calling BreakpadMiniDumpSystemInit
Installing breakpad exception handler for appid(steam)/version(1428965940)
Fontconfig warning: "/home/chris/.local/share/Steam/bin/panorama/etc/fonts/conf.d/41-repl-os-win.conf", line 148: Having multiple values in <test> isn't supported and may not work as expected
Fontconfig warning: "/home/chris/.local/share/Steam/bin/panorama/etc/fonts/conf.d/41-repl-os-win.conf", line 160: Having multiple values in <test> isn't supported and may not work as expected
Installing breakpad exception handler for appid(steam)/version(1428965940)

(steamwebhelper:26944): Gtk-WARNING **: Unable to locate theme engine in module_path: "adwaita",

(steamwebhelper:26944): Gtk-WARNING **: Unable to locate theme engine in module_path: "adwaita",
Compiled against SDL version 2.0.4 and linked against SDL version 2.0.4
/usr/share/themes/Adwaita/gtk-2.0/gtkrc:1163: error: unexpected identifier `direction', expected character `}'

(steamwebhelper:26944): Gtk-WARNING **: Unable to locate theme engine in module_path: "adwaita",

(steamwebhelper:26944): Gtk-WARNING **: Unable to locate theme engine in module_path: "adwaita",
/usr/share/themes/Adwaita/gtk-2.0/gtkrc:1163: error: unexpected identifier `direction', expected character `}'
COpenGLSurface::BInitialize: Current session is 
Installing breakpad exception handler for appid(steamwebhelper)/version(20150413151658)
Installing breakpad exception handler for appid(steamwebhelper)/version(1428938218)
Installing breakpad exception handler for appid(steamwebhelper)/version(20150413151658)
Installing breakpad exception handler for appid(steamwebhelper)/version(1428965940)
Installing breakpad exception handler for appid(steamwebhelper)/version(1428965940)
Installing breakpad exception handler for appid(steam)/version(1428965940)
Installing breakpad exception handler for appid(steam)/version(1428965940)
sh: /usr/bin/alienware_wmi_control.sh: No such file or directory
[0415/185318:ERROR:renderer_main.cc(227)] Running without renderer sandbox
Installing breakpad exception handler for appid(steam)/version(1.0)
Installing breakpad exception handler for appid(steam)/version(1.0)
Warning, someone is using SetHTTPRequestRequiresVerifiedCertificate on Linux, where it doesn't work, and we won't actually verifyAdding activate event to a panel(CommunityMenu) without a tab or selection index, the gamepad and keyboard can't get here.
Adding activate event to a panel(CommunityGameHub) without a tab or selection index, the gamepad and keyboard can't get here.
sh: /usr/bin/alienware_wmi_control.sh: No such file or directory
Installing breakpad exception handler for appid(steam)/version(1428965940)
HTTP Response for http://store.steampowered.com/api/featuredcategories/?extra=controller,&trailer=1&f=l: 200, 34757
HTTP Response for http://store.steampowered.com/api/messages/?cc=DE&l=english&gids=6912293361054424900,3978417740430800456: 200, 1069
HTTP Response for http://store.steampowered.com/api/messages/?cc=DE&l=english&gids=6912293361054424900,3978417740430800456: 200, 1069
HTTP Response for https://store.steampowered.com/api/featured/?cc=DE&l=english&f=l: 200, 35048
Installing breakpad exception handler for appid(steam)/version(1428965940)

OpenVR/bin/linux32/vrserver uses up exactly 100% of one cpu core.

Tried bith SteamVR current and SteamVR beta, with and without runtime, with intel and radeonsi. Everywhere it's the same: Just a completely black fullscreen window with 100% cpu usage from vrserver.