I GOT ENLIGHTENED. I know what changed since yesterday. I don't have my printer installed in the multisesat ubuntu, so I'm ocassionally booting into my Debian install where I have my multiseat setup based on a Xephyr approach, where both monitors are connected to the two heads of JUST ONE of the graphics cards. So today the monitor of seat-1 was connected to TWO cards. Hence seat0 saw two monitors and extended its desktop to both, and seat-1 also saw one monitor. When I unplugged the reduntant cable, it all behaves like yesterday: seat-1 wouldn't come back after resume. That's good and bad news: the good news it that the world still works as it is supposed, the bad news is that the seat-1 resume problem remains. I need a break...
-- You received this bug notification because you are a member of Ubuntu Multiseat, which is subscribed to the bug report. https://bugs.launchpad.net/bugs/1209008 Title: [SRU] X doesn't work for video cards with non-KMS drivers on non-seat0 seats Status in X.Org X server: Fix Released Status in xorg-server package in Ubuntu: Fix Released Status in xorg-server source package in Trusty: Fix Committed Bug description: [Impact] * In Xorg-server versions older than 1.16, if Xorg is started as a non-seat0 X server (i.e. if it was started with "-seat XXXX" option where "XXXX" != "seat0"), it only probes platform bus for graphics devices, leaving devices with non-KMS drivers (like NVIDIA proprietary drivers and old ones like xf86-video-siliconmotion) unreachable. Patch "xfree86_allow_fallback_to_pci_bus_probe_for_non_seat0.patch" from lp:~ubuntu-multiseat/xorg-server/trusty-matchseat fixes this. * systemd-logind has no intrinsic mechanism to assign non-KMS graphics devices to seats. In this case, one should tag another seat device (keyboard, USB hub, etc.) in udev as "master-of-seat", and provide a suitable xorg.conf for that seat. In order to avoid that a given xorg.conf affects other seats, it should be passed to Xorg via "-config xorg.conf.custom" option, which requires X server command line customization support in DM in use (GDM, for example, has no such support). Patch "xfree86_add_matchseat_key_to_xorg_conf.patch" from lp:~ubuntu- multiseat/xorg-server/trusty-matchseat introduces a new MatchSeat key for xorg.conf sections "Device", "Screen", and "ServerLayout", which will target a given seat only. Example file /etc/X11/xorg.conf.d/90-seat-1.conf: Section "Device" Identifier "card0" Driver "nvidia" Option "NoLogo" "True" # This section will only apply for seat-1 MatchSeat "seat-1" EndSection * systemd-logind can't handle any VT switching for non-seat0 seats, but Xorg-server older than 1.16 still opens VT even if it's started as a non-seat0 X server. This may lead to a race condition between X servers: if a non-seat0 one is started before a seat0 one, the former "steals" VTs from the later. If a seat0 X server can't open VTs, systemd-logind can't activate sessions for seat0, leaving user without sound or usb input support, for example. Patch "xfree86_keep_non_seat0_from_touching_vts.patch" from lp :~ubuntu-multiseat/xorg-server/trusty-matchseat fixes this. [Test Case] * Set up a multiseat system where your non-seat0 seats use non-KMS video drivers (you may need to tag another device in udev as "master- of-seat" in order to achieve it). * When LightDM/GDM tries to start a Xorg server for your non-seat0 seats, it will end up with the following error: "(EE) No devices found". * After applying xfree86_allow_fallback_to_pci_bus_probe_for_non_seat0.patch, you can configure your seats in LightDM by setting appropriate "xserver- config" properties for each seat. However, you can't configure them in GDM. * After applying xfree86_add_matchseat_key_to_xorg_conf.patch, configure your seats properly and restart LightDM/GDM services (or reboot your computer) repeatedly. In some iterations, it may happen that logind can't activate graphical sessions for seat0. If it occurs, check output of command "ps -FC Xorg" and you'll see that a non-seat0 Xorg server has a lower PID than seat0 one. Moreover, the non-seat0 has opened a TTY, while the seat0 hasn't. [Regression Potential] * Very low. All these patches were well tested in xorg-server "trusty" package available in ppa:ubuntu-multiseat/ppa. To manage notifications about this bug go to: https://bugs.launchpad.net/xorg-server/+bug/1209008/+subscriptions -- Mailing list: https://launchpad.net/~ubuntu-multiseat Post to : ubuntu-multiseat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-multiseat More help : https://help.launchpad.net/ListHelp
