Comment 0 for bug 1504220

I'm using a Lenovo laptop with an intel/nvidia Optimus compatible graphics solution. While being able to use prime-select to switch between those cards with Ubuntu 14.X and official nvidia driversit stopped working when switching to ubuntu 15.04 and newer drivers. I'm not sure when the problem first arises, but I'm stucking with it for almost 5 month.
In the meanwhile I stumbled upon errors in xorg.log pointing to insufficient permissions related to DRM and intel driver. I switched to a newer kernel 4.1.x and the xorg.log error had gone, but the general problem remains. A month ago I switched to a wily daily build to test if the bug still exists there. I did a fresh install but the problem is still the same.

ProblemType: Bug
DistroRelease: Ubuntu 15.10
Package: xorg 1:7.7+7ubuntu4
ProcVersionSignature: Ubuntu 4.2.0-14.16-generic 4.2.2
Uname: Linux 4.2.0-14-generic x86_64
NonfreeKernelModules: nvidia
.proc.driver.nvidia.registry: Binary: ""
.proc.driver.nvidia.version:
 NVRM version: NVIDIA UNIX x86_64 Kernel Module 355.11 Wed Aug 26 16:35:41 PDT 2015
 GCC version: gcc version 5.2.1 20151003 (Ubuntu 5.2.1-21ubuntu2)
ApportVersion: 2.19-0ubuntu1
Architecture: amd64
Date: Thu Oct 8 18:18:55 2015
DistUpgraded: Fresh install
DistroCodename: wily
DistroVariant: ubuntu
DkmsStatus:
 bbswitch, 0.7, 4.2.0-10-generic, x86_64: installed
 bbswitch, 0.7, 4.2.0-14-generic, x86_64: installed
 nvidia-355, 355.11, 4.2.0-14-generic, x86_64: installed
GraphicsCard:
 Intel Corporation 3rd Gen Core processor Graphics Controller [8086:0166] (rev 09) (prog-if 00 [VGA controller])
   Subsystem: Lenovo Device [17aa:21fc]
 NVIDIA Corporation GF108M [GeForce GT 620M] [10de:0de8] (rev a1) (prog-if 00 [VGA controller])
   Subsystem: Lenovo Device [17aa:21fc]
InstallationDate: Installed on 2015-09-12 (26 days ago)
InstallationMedia: Ubuntu 15.10 "Wily Werewolf" - Alpha amd64 (20150911)
MachineType: LENOVO 33643EG
ProcEnviron:
 LC_CTYPE=de_DE.UTF-8
 TERM=linux
 PATH=(custom, no user)
 LANG=de_DE.UTF-8
 SHELL=/usr/bin/zsh
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.2.0-14-generic.efi.signed root=UUID=55cf0b06-9493-479a-a524-07e52d5be60a ro noprompt persistent quiet splash vt.handoff=7
SourcePackage: xorg
UdevLog: Error: [Errno 2] No such file or directory: '/var/log/udev'
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 04/09/2015
dmi.bios.vendor: LENOVO
dmi.bios.version: GAETA0WW (2.60 )
dmi.board.asset.tag: Not Available
dmi.board.name: 33643EG
dmi.board.vendor: LENOVO
dmi.board.version: Not Available
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Not Available
dmi.modalias: dmi:bvnLENOVO:bvrGAETA0WW(2.60):bd04/09/2015:svnLENOVO:pn33643EG:pvrThinkPadS430:rvnLENOVO:rn33643EG:rvrNotAvailable:cvnLENOVO:ct10:cvrNotAvailable:
dmi.product.name: 33643EG
dmi.product.version: ThinkPad S430
dmi.sys.vendor: LENOVO
version.compiz: compiz 1:0.9.12.2+15.10.20151002-0ubuntu1
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.64-1
version.libgl1-mesa-dri: libgl1-mesa-dri 11.0.0-1ubuntu1
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 11.0.0-1ubuntu1
version.nvidia-graphics-drivers: nvidia-graphics-drivers-* N/A
version.xserver-xorg-core: xserver-xorg-core 2:1.17.2-1ubuntu9
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+git20150808-0ubuntu3
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.11-1ubuntu3
xserver.bootTime: Thu Oct 8 18:15:17 2015
xserver.configfile: /etc/X11/xorg.conf
xserver.errors:

xserver.logfile: /var/log/Xorg.0.log
xserver.version: 2:1.17.2-1ubuntu9