DRI can only be used by one X server at a time, so compiz can only used by one user

[unggnu]

Binary package hint: compiz

I am using Gutsy. If I create a second desktop user with admin rights and change between session to him compiz isn't activated even if desktop effects are activated. If I de- and activate them again I got after some time the error message: "Desktop effects could not be enabled". It is only possible to use compiz for the second user if I deactivate compiz for the first one and restart X.

[Freedesktop-farnz (freedesktop-farnz)]

Created an attachment (id=3116)
Xorg.0.log

This is the Xorg log for the first instance of the server.

[Freedesktop-farnz (freedesktop-farnz)]

Created an attachment (id=3117)
Xorg.1.log

This is the Xorg log for the second instance of the server (the one that
doesn't have a full set of acceleration).

[Freedesktop-farnz (freedesktop-farnz)]

Created an attachment (id=3118)
xorg.conf

In case it's relevant, my xorg.conf - any other relevant files can be supplied.

[Dan Ballard (haplo)]

I'm using 6.8.99.15 with a i915 graphics chip and am also experienceing the same
problem. It's kind of a bummer since I normally rin my games of a second X
session becasue with the instability of binary games and the beta i915 driver
they crash a bunch and I prefer it not taking down my main X session. Oh well
for now. Still, thanks for getting the i915 working :)

[Ns03ja (ns03ja)]

I get the same issue with a Radeon 7500 Mobility. Interestingly though, I
still get EXA acceleration and such for both X servers, even if no 3D
acceleration is available for the second X server. I believe the proprietary
NVidia drivers can 3D accelerate 2+ X servers, although I don't have access to
any NVidia hardware at the moment, so I can't check for sure, but it should be
possible for Radeons too.

[unggnu (unggnu)]

Binary package hint: compiz

I am using Gutsy. If I create a second desktop user with admin rights and change between session to him compiz isn't activated even if desktop effects are activated. If I de- and activate them again I got after some time the error message: "Desktop effects could not be enabled". It is only possible to use compiz for the second user if I deactivate compiz for the first one and restart X.

[Travis Watkins (amaranth)]

This is because DRI can only be used by the one X server.

[unggnu (unggnu)]

I experiencing the same issue. I have an Intel 915 chipset and it isn't possible to use Compiz for more than one user.
I am using Ubuntu 7.10 Testing.

[Travis Watkins (amaranth)]

Since this would require a rather large change in the way 3d works on X it's not something we can ever do in Ubuntu and probably won't be happening upstream any time soon.

[rettichschnidi (rettichschnidi)]

I'm currently using Tribe5 and I found exactly this "problem". Since there are "Desktop Effects" enabled by default, there should be at least a notice in "gnome-appearance-properties" -> "Desktop Effects" that they are only available for the first user of the X-Server-session.
A simple "Desktop effects could not be enabled" is IMHO not sufficient enough to let the user understand why there is no eye candy.

[Kyle M Weller (kylew)]

i can confirm this issue, and I dont believe desktop effects should be in gutsy if more than 1 user cannot use it... Also, here is an idea for a quick fix, on switching users have the switch user applet disable desktop effects for the current session to enable on the other users session. This is a simple yet effective way untill we can find a fix for allowing X to handle more.

[Jeremy Visser (jeremy-visser)]

Huh? This has historically worked fine for me. I have previously run games simultaneously on different X servers — e.g. I used to run Xgl with Compiz on :0, and run Quake 3 at the same time on :1. I can also have multiple users logged on with both running Compiz.

[Travis Watkins (amaranth)]

It only works with nvidia and (I think) fglrx. The intel and ati drivers are the ones with this problem.

[Jeremy Visser (jeremy-visser)]

Typical. I have never regretted the day I chose NVIDIA. :)

[Alexander Nevskiy (kepkin)]

I can't afford a 12'' laptop with nvidia...

[Brandon Sandrowicz (bsandrow)]

Travis, if it works for nvidia and ati's proprietary drivers, then how is this a limitation of the X-Server? Wouldn't it just be a limitation of specific drivers? and even if it's a limitation of X that they worked around, it means that a work-around is possible.

Just to add to the discussion, since there is no specific information here, is this link:

http://forum.compiz-fusion.org/showthread.php?t=6944

Supposedly this will be solved with DRI2, but I don't know when that is planned by the X.org folks. Which also comes back to the question of how the nvidia / ati (fglrx) drivers work yet other don't if this really is just a limitation of DRI.

[Brandon Sandrowicz (bsandrow)]

Also wanted to add support for rettichschnidi's suggestion. If Hardy Heron is pushed out the door with Desktop Effects enabled and there is a known limitation of X that you can't run Desktop Effects as a second user when "Switching Users," it makes no sense to leave it at a cryptic error message.

Users that don't know any better will just get frustrated and have a degraded user experience if they run into this problem with only an error message of "Sorry, couldn't do that" without some explanation of why. Just saying that "2 users can't use desktop effects at the same time" would be enough to allow people an idea of what is going on, rather than just forcing them to run into the brick wall of nothing but "it won't work."

[Travis Watkins (amaranth)]

This is a problem that needs changes in the drm, dri, and ddx. The nvidia driver avoids this by not using the drm or dri frameworks. I believe fglrx has the same problems as the open source drivers as they use the same infrastructure.

[Nicolò Chieffo (yelo3)]

I have also an intel 965 card, and I can run compiz also in a secondary X session. I have not tried more than 2 sessions, tough.

[ibizatunes (ibizatunes)]

 have a ATI Radeon 9200, and i have the same issue..... on 8.04 and 7.10
i like kyle's idea "here is an idea for a quick fix, on switching users have the switch user applet disable desktop effects for the current session to enable on the other users session. This is a simple yet effective way untill we can find a fix for allowing X to handle more"

[ibizatunes (ibizatunes)]

Just having a think about this problem, it should be given some a reasonably high priority to be fixed!!

1st reason is ubuntu (dell) sell laptop / desktops, with Intel open source drivers installed, Its not expectable if you buy a pc and there is a major driver issue like this (this issue needs to be fixed, i cant tell friends to buy ubuntu desktop / laptops if only 1 person can user the machine, then have to reboot, then another person can use it) - not acceptable, user wont buy the product
2nd can potentially can effect ubuntu desktop sales
3rd reason, is that ubuntu (linux in general) works on older machine much better than new hardware does, if desktop effects can be enable (it shouldnt have such a major flaw in the drivers)

[ibizatunes (ibizatunes)]

Just having a think about this problem, it should be given some a reasonably high priority to be fixed!!

1st reason is Ubuntu (dell) sell laptop / desktops, with Intel open source drivers installed, Its not expectable if you buy a pc and there is a major driver issue like this (this issue needs to be fixed, i cant tell friends to buy ubuntu desktop / laptops if only 1 person can user the machine, then have to reboot, then another person can use it) - not acceptable, user wont buy the product
2nd can potentially can effect ubuntu desktop sales
3rd reason, is that Ubuntu (linux in general) works on older machine much better than new hardware does, if desktop effects can be enable (it shouldn't have such a major flaw in the drivers)

[ibizatunes (ibizatunes)]

Sorry about the double post
One more point! ubuntu has 10million + users, i would expect that this issue affect at least 5% of the total, that is 50k worth of users (at least)
it affect them even if they dont know about the flaw, this need to be fix asap!!

[Timo Aaltonen (tjaalton)]

A couple of things:

1) this bug is a well known limitation, so no need to confirm anything. Thank you.
2) raising the bug importance doesn't make it fixed any sooner. Upstream is working on the infrastructure as we speak. We should have something ready for Intrepid.

kyle: temporarily falling back to metacity would put all the apps on the first virtual screen, so it's definately not an option.

[Nicolò Chieffo (yelo3)]

are you sure this is an xorg limit? since it works with intel, this
should be only an ati driver problem

[Brandon Sandrowicz (bsandrow)]

Nicolo: I'm running intel drivers, and I can only get Compiz-Fusion to run as the first user that logs into X. I'm on a ThinkPad X41.

[Nicolò Chieffo (yelo3)]

I'm sure I did it: I did system, exit, switch users, and then selected
another user. It also worked switching the desktop with ctrl-alt-f7.
they both had compiz ruinning.

[Travis Watkins (amaranth)]

That is...not possible. It requires drm multi-master support which is still on a user branch in fd.o git because work only just started on it.

[Nicolò Chieffo (yelo3)]

I'm sorry, it works for me, I made a video with my cellphone as a proof

[Travis Watkins (amaranth)]

This must be some early April Fools' Day joke or something, that is _not possible_. You must have an nvidia card for that to be working unless you've built drm, mesa, Xorg, and intel from certain git branches.

[Nicolò Chieffo (yelo3)]

Intel x3100 here, and april fools day is tomorrow!
The only thing is that I'm running kernel 2.6.25-rc6 from fedora 9.
might it be that?

[Brandon Sandrowicz (bsandrow)]

Could it be possible that he's running some other Intel driver that
doesn't use DRM?

[Adam K Kirchhoff (adamk-voicenet)]

All intel drivers use the DRM.

Nicolò, could we see your /var/log/Xorg.0.log file?

Adam

[Nicolò Chieffo (yelo3)]

If you need it yes, but I've just done a test. Booting with the ubuntu kernel does not work. It works only using the fedora 9 kernel
So it must be something new in 2.6.25 kernels

I have attached the second X session log, which says "DRM open master succeeded."

[Travis Watkins (amaranth)]

airlied must have pushed the multi-master stuff to rawhide, he is the one working on it for the intel driver. That's good news then, means we'll be able to use it in intrepid. :)

[Nicolò Chieffo (yelo3)]

This means that the kernel support is enough for this feature!

[Brandon Sandrowicz (bsandrow)]

Nicolo, I know this is a little off-topic here, but any
links/howto/instructions on how you've setup Ubuntu to boot to the
Fedora 9 kernel? I'd like to get 'multi-master' working on my laptop
if it's available now. Or are you just dual-booting Fedora 9 and
Ubuntu with the same /home mounted or something?

[Travis Watkins (amaranth)]

No, this needs driver support too because the drm interface was redesigned. He must be actually using fedora 9.

[Nicolò Chieffo (yelo3)]

I'm using ubuntu with fedora 9 kernel.
I downloaded the rpm,
I extracted it to /
I executed update-initramfs -k
all and I executed update-grub

[nadavkav (nadavkav)]

i confirm this issue with ubuntu 8.10 on
 VGA compatible controller: Intel Corporation 82915G/GV/910GL Integrated Graphics Controller (rev 04)

[unggnu (unggnu)]

Closing since current -intel, -radeon and noveau should support DRI2.

[unggnu (unggnu)]

Couldn't this bug be closed, at least with Lucid?

All three big graphic drivers (-intel,-radeon and -nouveau) support DRI2 so this is no problem anymore.