Comment 24 for bug 1209008

Revision history for this message
Laércio de Sousa (lbssousa) wrote : Re: [Bug 1209008] Re: [SRU] X doesn't work for video cards with non-KMS drivers on non-seat0 seats

Andrzej, please paste here the xorg.conf you've written for your NVIDIA
card, as well as your /var/log/Xorg.1.log, when you use the proprietary
driver.

Em sáb, 13 de dez de 2014 19:20, Andrzej Pietrasiewicz <
<email address hidden>> escreveu:

> ** Tags added: verification-failed
>
> --
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> 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.
>
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