Bug 19223

Summary:	Parallel X servers do not work
Product:	xorg	Reporter:	Arie Skliarouk <skliarie>
Component:	Driver/nouveau	Assignee:	Nouveau Project <nouveau>
Status:	RESOLVED INVALID	QA Contact:	Xorg Project Team <xorg-team>
Severity:	normal
Priority:	medium	CC:	nsoranzo
Version:	git
Hardware:	Other
OS:	All
Whiteboard:
i915 platform:		i915 features:

Description Arie Skliarouk 2008-12-21 13:21:35 UTC

ubuntu 8.10 has a nice feature of switching users using fast-user-switch. If I understand correctly, it somehow stops the current X-Windows server without destroying already open windows, and then starts the new X-Windows server, on behalf of user you want to switch to.

For some reason, stopping of Nouveau-powered X-Server always returns faulure, with following error message in /var/log/Xorg.0.log

Fatal server error:
xf86OpenConsole: VT_WAITACTIVE failed: Interrupted system call

Because of that, the fast-user-switch never proceeds to second part of starting another X-Windows, and instead returns to the previous X session with obscure error about inability to start X-Windows.

Card: 
01:00.0 VGA compatible controller: nVidia Corporation NV34 [GeForce FX 5200] (rev a1)

driver: xserver-xorg-video-nouveau 1:0.0.10~git20081124-0~ppa1

Comment 1 Arie Skliarouk 2008-12-21 13:32:42 UTC

I think I have misunderstood the way the fast user switching works...

Turns out the system starts separate X-Windows server just for the new user. In case of Nouveau, the Xorg.20.log shows following error message:

...
drmOpenDevice: open result is 10, (OK)
drmOpenByBusid: drmOpenMinor returns 10
drmOpenByBusid: drmGetBusid reports pci:0000:01:00.0
(II) [drm] DRM interface version 1.0
(EE) [drm] Could not set DRM device bus ID.
(EE) NOUVEAU(0): [dri] DRIScreenInit failed.  Disabling DRI.

Fatal server error:
AddScreen/ScreenInit failed for driver 0

And the fast switch fails with error of unability to start X-server.

Comment 2 Pekka Paalanen 2008-12-21 14:19:02 UTC

Currently Nouveau does not support multiple X servers running parallel. Nouveau requires DRM/DRI support, and the X server needs to get to be the DRI master for that. This would require multi-master support throughout the graphics stack, and it is still under development. This is not (yet) a Nouveau-specific bug, Nouveau is just the only driver that refuses to start a second X server at all (other drivers only miss DRI support on other X servers).

Changed the summary to a little more descriptive.

Comment 3 Ilia Mirkin 2013-08-18 18:09:18 UTC

It appears that this bug report has laid dormant for quite a while. Sorry we haven't gotten to it. Since we fix bugs all the time, chances are pretty good that your issue has been fixed with the latest software. Please give it a shot. (Linux kernel 3.10.7, xf86-video-nouveau 1.0.9, mesa 9.1.6, or their git versions.) If upgrading to the latest isn't an option for you, your distro's bugzilla is probably the right destination for your bug report.

In an effort to clean up our bug list, we're pre-emptively closing all bugs that haven't seen updates since 2011. If the original issue remains, please make sure to provide fresh info, see http://nouveau.freedesktop.org/wiki/Bugs/ for what we need to see, and re-open this one.

Thanks,

The Nouveau Team

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