I have a kiosk-style host running Ubuntu Server 14.04. I'm trying to set it up to play some videos, TV-like. Sometimes it needs to play Youtube playlists and other web-based video streaming services etc., so a browser window seems to be necessary.For this purpose I installed a barebones X.org without a desktop environment and it works.However, because the administration is over network and the host doubles as a a file and web server (this is a home project), I'm a bit security conscious and I'd like to run X as non-root. I already checked https://wiki.ubuntu.com/X/Rootless, but it seems dated: running X with -nohwaccess complains:/usr/bin/Xorg vt8 -retro -sharevts -nohwaccess -logfile /tmp/Xorg.U.log :1...Fatal server error:(EE) Unrecognized option: -nohwaccessIf I take the flag off, it starts but fails right away:Loading extension GLXxf86EnableIOPorts: failed to set IOPL for I/O (Operation not permitted)Edit: Oops, I can't apparently read! The FATAL error why Xorg terminates is not that, it's this, just after the xf86EnableIOPorts warning:(--) Depth 24 pixmap format is 32 bppUnable to retrieve masterFatal server error:[ 38106.045] (EE) AddScreen/ScreenInit failed for driver 0Whereas running with sudo, it emits:(--) Depth 24 pixmap format is 32 bppRADEON(0): [DRI2] Setup complete... and so forth.It seems like a permission problem, but I've set all the rights mentioned in the wiki article:videoplayer@yuunagi:/usr/bin$ ls -la /dev/tty8crw-rw---- 1 videoplayer root 4, 8  1 13 02:09 /dev/tty8 /dev/event/* have o+rw set,The user videoplayer belongs to both video and audio groups:videoplayer@yuunagi:/usr/bin$ cat /etc/group | grep videoplayeraudio:x:29:videoplayervideo:x:44:videoplayervideoplayer:x:999:What I am missing here?Edit: Btw. before anybody points it out: I have KMS enabled. Kernel log says so, (open-source Radeon drivers with DRM in function) and X.org logs says so: [KMS] Kernel modesetting enabled.Edit2: strace reveals the following:Opening a GPU device file succeeds:open(/dev/dri/card0, O_RDWR)          = 9After that, there's tens of succeeding ioctrls to that file, like this:ioctl(9, 0xc0106407, 0x7fff66772190)    = 0And then, last succeeding ioctl:ioctl(9, TUNER_SET_CONFIG, 0x7fff667722b0) = 0After that, a fail:ioctl(9, 0x641e, 0)  = -1 EACCES (Permission denied)Unable to retrieve masterBtw. the accessed GPU dev file has following permissions:videoplayer@yuunagi:/usr/bin$ ls -la /dev/dri/card0crw-rw----+ 1 root video 226, 0  1 13 02:09 /dev/dri/card0
Running X without root
ubuntu;xorg