Auto screen lock doesnt work

[Shoham Peller]

Under System Settings -> Brightness & Lock, I set the Lock to be ON, and the "Lock Screen After" to 30 seconds (see attached screenshot), But the screen doesn't lock after 30 seconds, or never.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: xorg 1:7.7+1ubuntu8.1
ProcVersionSignature: Ubuntu 3.13.0-39.66-generic 3.13.11.8
Uname: Linux 3.13.0-39-generic x86_64
NonfreeKernelModules: nvidia
.proc.driver.nvidia.gpus.0: Error: [Errno 21] Is a directory: '/proc/driver/nvidia/gpus/0'
.proc.driver.nvidia.registry: Binary: ""
.proc.driver.nvidia.version:
 NVRM version: NVIDIA UNIX x86_64 Kernel Module 331.113 Mon Dec 1 21:08:13 PST 2014
 GCC version: gcc version 4.8.2 (Ubuntu 4.8.2-19ubuntu1)
.tmp.unity.support.test.0:

ApportVersion: 2.14.1-0ubuntu3.10
Architecture: amd64
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CompositorRunning: compiz
CompositorUnredirectDriverBlacklist: '(nouveau|Intel).*Mesa 8.0'
CompositorUnredirectFSW: true
CurrentDesktop: Unity
Date: Sun Apr 26 20:56:18 2015
DistUpgraded: Fresh install
DistroCodename: trusty
DistroVariant: ubuntu
ExtraDebuggingInterest: Yes
GraphicsCard: NVIDIA Corporation GT215 [GeForce GT 240] [10de:0ca3] (rev a2) (prog-if 00 [VGA controller])
InstallationDate: Installed on 2014-11-05 (172 days ago)
InstallationMedia: Ubuntu 14.04.1 LTS "Trusty Tahr" - Release amd64 (20140722.2)
MachineType: Gigabyte Technology Co., Ltd. H55M-UD2H
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.13.0-39-generic root=UUID=df2c797a-098e-4429-8213-9df0751f2de2 ro quiet splash
SourcePackage: xorg
Symptom: display
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 08/20/2010
dmi.bios.vendor: Award Software International, Inc.
dmi.bios.version: F11
dmi.board.name: H55M-UD2H
dmi.board.vendor: Gigabyte Technology Co., Ltd.
dmi.board.version: x.x
dmi.chassis.type: 3
dmi.chassis.vendor: Gigabyte Technology Co., Ltd.
dmi.modalias: dmi:bvnAwardSoftwareInternational,Inc.:bvrF11:bd08/20/2010:svnGigabyteTechnologyCo.,Ltd.:pnH55M-UD2H:pvr:rvnGigabyteTechnologyCo.,Ltd.:rnH55M-UD2H:rvrx.x:cvnGigabyteTechnologyCo.,Ltd.:ct3:cvr:
dmi.product.name: H55M-UD2H
dmi.sys.vendor: Gigabyte Technology Co., Ltd.
version.compiz: compiz 1:0.9.11.3+14.04.20141104-0ubuntu1
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.56-1~ubuntu2
version.libgl1-mesa-dri: libgl1-mesa-dri 10.1.3-0ubuntu0.4
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 10.1.3-0ubuntu0.4
version.nvidia-graphics-drivers: nvidia-graphics-drivers N/A
version.xserver-xorg-core: xserver-xorg-core 2:1.15.1-0ubuntu2.7
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.8.2-1ubuntu2
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:7.3.0-1ubuntu3.1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.910-0ubuntu1.4
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.10-1ubuntu2
xserver.bootTime: Sun Apr 26 20:17:25 2015
xserver.configfile: default
xserver.errors:
 open /dev/fb0: No such file or directory
 Server terminated successfully (0). Closing log file.
xserver.logfile: /var/log/Xorg.0.log
xserver.outputs:

xserver.version: 2:1.15.1-0ubuntu2.7

[Shoham Peller (shoham-peller)]

After debugging a bit, the bug seems in gnome. The code successfully runs:
    g_settings_set (self->priv->lock_settings, "lock-delay", "u", delay);
and in the shell I can indeed see:
    $ gsettings get org.gnome.desktop.screensaver lock-delay
    uint32 30

So maybe there's something wrong with gnome? Or maybe gnome can't lock the unity session?