@Rober, I think they are different.
I found there is a solution that can fix the issue. https://wiki.archlinux.org/index.php/Touchpad_Synaptics#Xorg.log.0_shows_SynPS.2F2_Synaptics_touchpad_can_not_grab_event_device.2C_errno.3D16 I have add GrabEventDevice=0 option to xorg.conf and it works fine now. Mouse cursor now can move after session is changed. ** Changed in: oem-priority Status: Incomplete => Confirmed -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to unity-greeter in Ubuntu. https://bugs.launchpad.net/bugs/1399096 Title: Touchpad lost function after switch from guest to user account Status in OEM Priority Project: Confirmed Status in unity-greeter package in Ubuntu: New Bug description: Reproduce steps: 1) Change account to guest by click guest account on the menu. 2) Change account to user again 3) Touchpad lost its function. When the touchpad becomes malfunction, there are some messages in /var/log/Xorg.0.log [ 282.908] (WW) synaptics: SynPS/2 Synaptics TouchPad: can't grab event device, errno=16 [ 282.940] [dix] couldn't enable device 11 [ 282.940] setversion 1.4 failed: Permission denied ProblemType: Bug DistroRelease: Ubuntu 14.04 Package: xserver-xorg-input-synaptics 1.7.4-0ubuntu1 ProcVersionSignature: Ubuntu 3.13.0-41.69stella1-generic 3.13.11.10 Uname: Linux 3.13.0-41-generic x86_64 ApportVersion: 2.14.1-0ubuntu3.2 Architecture: amd64 CurrentDesktop: Unity Date: Thu Dec 4 02:25:41 2014 DistUpgraded: Fresh install DistributionChannelDescriptor: # This is a distribution channel descriptor # For more information see http://wiki.ubuntu.com/DistributionChannelDescriptor canonical-oem-stella-neihu-trusty-amd64-20141125-0 DistroCodename: trusty DistroVariant: ubuntu InstallationDate: Installed on 2014-12-04 (0 days ago) InstallationMedia: Ubuntu 14.04 "Trusty" - Build amd64 LIVE Binary 20141125-01:45 Lsusb: Bus 001 Device 003: ID 0bda:5776 Realtek Semiconductor Corp. Bus 001 Device 002: ID 8087:8000 Intel Corp. Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 003 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub MachineType: Hewlett-Packard HP 15 Notebook PC ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.13.0-41-generic root=UUID=f7c1e040-6471-4e14-9e77-bb406b63fad3 ro quiet splash video.use_native_backlight=1 radeon.modeset=0 nouveau.modeset=0 vt.handoff=7 SourcePackage: xserver-xorg-input-synaptics UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 10/28/2014 dmi.bios.vendor: Insyde dmi.bios.version: F.32 dmi.board.asset.tag: Type2 - Board Asset Tag dmi.board.name: 2211 dmi.board.vendor: Hewlett-Packard dmi.board.version: 86.45 dmi.chassis.asset.tag: Chassis Asset Tag dmi.chassis.type: 10 dmi.chassis.vendor: Hewlett-Packard dmi.chassis.version: Chassis Version dmi.modalias: dmi:bvnInsyde:bvrF.32:bd10/28/2014:svnHewlett-Packard:pnHP15NotebookPC:pvr097F120000005F00001620100:rvnHewlett-Packard:rn2211:rvr86.45:cvnHewlett-Packard:ct10:cvrChassisVersion: dmi.product.name: HP 15 Notebook PC dmi.product.version: 097F120000005F00001620100 dmi.sys.vendor: Hewlett-Packard version.compiz: compiz 1:0.9.11.2+14.04.20140714-0ubuntu1 version.ia32-libs: ia32-libs N/A version.libdrm2: libdrm2 2.4.52-1 version.libgl1-mesa-dri: libgl1-mesa-dri 10.1.3-0ubuntu0.1 version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A version.libgl1-mesa-glx: libgl1-mesa-glx 10.1.3-0ubuntu0.1 version.xserver-xorg-core: xserver-xorg-core 2:1.15.1-0ubuntu2 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 2:2.99.910-0ubuntu1.1stella3 version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.10-1ubuntu2 xserver.bootTime: Thu Dec 4 02:21:16 2014 xserver.configfile: default xserver.errors: xserver.logfile: /var/log/Xorg.0.log xserver.outputs: product id 17900 vendor AUO xserver.version: 2:1.15.1-0ubuntu2 To manage notifications about this bug go to: https://bugs.launchpad.net/oem-priority/+bug/1399096/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp