I met with the same bug in Ubuntu 16.04.1 (amd64): 2 NVIDIA adapters with DVI and HDMI connectors on each of them, 4 identical Samsung monitors, 4th monitor is dead, 3rd is sometimes garbled, sometimes is OK. All the error messages described by Martin are the same. Luckily in #2 he provided the method which cures the bug with ATI cards in Fedora. I decided to try it with Nouveau driver in Ubuntu and it worked! I downloaded the sources using 'apt-get source xserver-xorg-video-nouveau', found the string in drmmode_display.c which checks whether HAS_DIRTYTRACKING2 is defined and fixed it. Then I compiled the driver and replaced '/usr/lib/xorg/modules/drivers/nouveau_drv.so' with the fixed version. After reboot all 4 monitors were working on login screen, '~/.config/monitors.xml' was created properly and all monitors were present when I logged in. I'm attaching the patch. Maybe the developers will notice it and fix the Nouveau driver? (BTW, ATI driver in Ubuntu 16.04 seems already fixed - I checked its sources and the mentioned string is already in place in drmmode_display.c)
** Patch added: "Fixes improper handling of 3rd and 4th monitors" https://bugs.launchpad.net/ubuntu/+source/xorg-server/+bug/1597437/+attachment/4802770/+files/nouveau_drv.patch ** Package changed: xorg-server (Ubuntu) => xserver-xorg-video-nouveau (Ubuntu) -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xorg-server in Ubuntu. https://bugs.launchpad.net/bugs/1597437 Title: X with nouveau driver, 2 nvidia cards, 4 monitors, does not use all monitors To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-nouveau/+bug/1597437/+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
