Ubuntu 15.10의 Bumblebee(Primus 및 Optirun) 오류

Question

터미널(primus 및 optirun cmd가 있는 모든 프로그램에서 동일한 결과):

$ primusrun steam
2015/10/28 17:41:41 socat[2135] E connect(5, AF=1 "/var/run/bumblebee.socket", 27): No such file or directory
Running Steam on ubuntu 15.10 64-bit
STEAM_RUNTIME is enabled automatically
Installing breakpad exception handler for appid(steam)/version(1445896823)
primus: fatal: failed to connect to Bumblebee daemon: Tiedostoa tai hakemistoa ei ole
[2015-10-28 17:41:43] Startup - updater built Oct 26 2015 14:20:15
[2015-10-28 17:41:43] Opted in to client beta 'publicbeta' via beta file
You are in the 'publicbeta' client beta.