Assuming the bug is in journal-1.txt, it looks like the nouveau kernel graphics driver that's crashing. To solve that I suggest installing an official Nvidia driver from the 'Additional Drivers' app.
** Package changed: xorg (Ubuntu) => linux (Ubuntu) ** Summary changed: - Xorg freeze + [nouveau] Xorg freeze ** Tags added: nouveau ** Summary changed: - [nouveau] Xorg freeze + [nouveau] Screen freeze -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xorg in Ubuntu. https://bugs.launchpad.net/bugs/2080814 Title: [nouveau] Screen freeze To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2080814/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : ubuntu-x-swat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp
