install the package http://launchpadlibrarian.net/262502497/xserver- xorg-core-lts-vivid_1.17.1-0ubuntu3.1~trusty1.1_amd64.deb and tested again, this issue has gone.
** Tags removed: verification-needed ** Tags added: verification-done -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to xorg-server in Ubuntu. https://bugs.launchpad.net/bugs/1586260 Title: System freeze & no display if set External monitor as primary (Performance mode) Status in xorg-server package in Ubuntu: Fix Released Status in xorg-server-lts-vivid package in Ubuntu: Invalid Status in xorg-server source package in Trusty: Invalid Status in xorg-server-lts-vivid source package in Trusty: Fix Committed Status in xorg-server source package in Xenial: New Status in xorg-server-lts-vivid source package in Xenial: Invalid Status in xorg-server source package in Yakkety: Fix Released Status in xorg-server-lts-vivid source package in Yakkety: Invalid Bug description: [Impact] System freeze & no display if set External monitor as primary (Performance mode) [Test case] 1. Setup Graphic mode to Performance mode 2. Plug External monitor with HDMI 3. Set display mode to External monitor only is pass 4. Set display mode to Extend/ Mirror mode Expected results: External monitor can be set as primary normally Actual results: System freeze & no display if set External monitor as primary (Performance mode) [Regression potential] Unknown right now, upstream review pending. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xorg-server/+bug/1586260/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : [email protected] Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp
