libGL error: failed to open drm device: Permission denied

[Ales]

After some update (unfortunately I'm not sure what) if I try to play a videofile (e.g. mpv movie.mkv) I get this error:

libGL error: failed to open drm device: Permission denied

I think from this message is not very clear why is that.

I figured out I was not in "video" group: "id user_name"

I had to do this: "usermod -aG video user_name " and then restart X (logout, login). After that it works again.

So I suspect there is some problem there. Why libGL cannot be used without membership in video group or why a regular user is not in video group.

ProblemType: Bug
DistroRelease: Ubuntu 15.10
Package: xorg 1:7.7+7ubuntu4
ProcVersionSignature: Ubuntu 4.2.0-25.30-generic 4.2.6
Uname: Linux 4.2.0-25-generic x86_64
ApportVersion: 2.19.1-0ubuntu5
Architecture: amd64
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CompositorRunning: None
Date: Thu Jan 28 12:54:51 2016
DistUpgraded: Fresh install
DistroCodename: wily
DistroVariant: ubuntu
DkmsStatus: fglrx-core, 15.201, 4.2.0-25-generic, x86_64: installed
ExtraDebuggingInterest: I just need to know a workaround
GraphicsCard:
 Intel Corporation Haswell-ULT Integrated Graphics Controller [8086:0a16] (rev 0b) (prog-if 00 [VGA controller])
   Subsystem: Hewlett-Packard Company Device [103c:2248]
InstallationDate: Installed on 2015-10-23 (96 days ago)
InstallationMedia: Kubuntu 15.10 "Wily Werewolf" - Release amd64 (20151021)
MachineType: Hewlett-Packard HP ProBook 450 G2
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.2.0-25-generic root=UUID=c9e0c6ee-c8a4-4d1a-a46e-a3b79c38f774 ro
SourcePackage: xorg
Symptom: display
UdevLog: Error: [Errno 2] No such file or directory: '/var/log/udev'
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 11/26/2015
dmi.bios.vendor: Hewlett-Packard
dmi.bios.version: M74 Ver. 01.16
dmi.board.name: 2248
dmi.board.vendor: Hewlett-Packard
dmi.board.version: KBC Version 67.24
dmi.chassis.type: 10
dmi.chassis.vendor: Hewlett-Packard
dmi.modalias: dmi:bvnHewlett-Packard:bvrM74Ver.01.16:bd11/26/2015:svnHewlett-Packard:pnHPProBook450G2:pvrA3008CD10003:rvnHewlett-Packard:rn2248:rvrKBCVersion67.24:cvnHewlett-Packard:ct10:cvr:
dmi.product.name: HP ProBook 450 G2
dmi.product.version: A3008CD10003
dmi.sys.vendor: Hewlett-Packard
version.compiz: compiz N/A
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.64-1
version.libgl1-mesa-dri: libgl1-mesa-dri 11.0.2-1ubuntu4
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 11.0.2-1ubuntu4
version.xserver-xorg-core: xserver-xorg-core 2:1.17.2-1ubuntu9.1
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.9.2-1ubuntu1
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:7.5.0+git20150819-0ubuntu1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20150808-0ubuntu4
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.11-1ubuntu3
xserver.bootTime: Wed Jan 27 22:49:34 2016
xserver.configfile: /etc/X11/xorg.conf
xserver.errors: Screen 1 deleted because of no matching config section.
xserver.logfile: /var/log/Xorg.0.log
xserver.outputs:
 product id 1125
 vendor LGD
xserver.version: 2:1.17.2-1ubuntu9.1

[Andreas Mohr (andi)]

Encountered very similar things (error message usability issue).
--> filed improvement suggestion at https://bugs.freedesktop.org/show_bug.cgi?id=98163

[Daniel van Vugt (vanvugt)]

Thank you for reporting this bug to Ubuntu.
Ubuntu 15.10 (wily) reached end-of-life on July 28, 2016.

See this document for currently supported Ubuntu releases:
https://wiki.ubuntu.com/Releases

We appreciate that this bug may be old and you might not be interested in discussing it any more. But if you are then please upgrade to the latest Ubuntu version and re-test. If you then find the bug is still present in the newer Ubuntu version, please add a comment here telling us which new version it is in and change the bug status to Confirmed.