Please attach your xorg log and your dmesg.

Created attachment 29761 [details]
the dmesg

Created attachment 29762 [details]
/var/log/Xorg.0.log

I tried it now with GNOME and it's the same symptoms, black screen.
This worked fine in ubuntu 9.10 so it's a regression.

(well, not black screen, black desktop when I have compiz, desktop OK with metacity, applications windows are always OK).

This is more likely a 3D driver issue.

using the mesa from ubuntu karmic, 7.6.0~git20090817.

it's definitely mesa. If I compile certain older versions of mesa it works.

I attempted to bisect it, but it's a nightmare because older versions of mesa depend on older versions of some libraries (dri2proto, libdrm) potentially with some compilation flags. I put really a lot of effort but I didn't manage to bisect it to the end.

my current problem is that bisect wants me to test versions around february and they all completely freeze my Xorg and I must reset the computer every time. I skip them, get a version close to that one and it's again the same thing, very tiring. I don't know if they were actually buggy if I'm compiling something wrong.

7a1dbcabf3f2599c90665e7fdbdba8698528841a 2009-02-17 -> when enabling 3d no windows, just background+mouse. can't switch to VT. SKIP.

0a8cba9a65e6ec1159a08725d2101e7eabb4526b -> when enabling 3d no windows, just background+mouse. can't switch to VT. SKIP.

5325f8624093bb1ec30d581b4ff64218ceab99f9 -> when enabling 3d no windows, just background+mouse. can't switch to VT. SKIP.

646325a5efb3cf4157623d115d6d8fa36f0b357d -> when enabling 3d no windows, just background+mouse. can't switch to VT. SKIP.

Well here is what I wrote down about all the versions that I tried, well for sure some versions work so the problem is really in mesa. Maybe if you tell me how to get past this bad series of freezes now I can try going on but I'm really tired of this by now :-(

git bisect bad 69c7fc128c59bf72df461dbd583bf9794d9ed34d

git bisect good bf1e6581a56884c383e5446d84c56b39a7f4e0a0

git bisect good 126d62edd18f22ff9e744efea81e0383cd0a19c5

git bisect bad 6be2bc56af5c0d281d07e427863789e949904db1

git bisect good 609cc9c1395a9417e56224c8754d799f8b7a5573 2009-01-22 18:18:04

7a1dbcabf3f2599c90665e7fdbdba8698528841a 2009-02-17 -> when enabling 3d no windows, just background+mouse. can't switch to VT. SKIP.

0a8cba9a65e6ec1159a08725d2101e7eabb4526b -> when enabling 3d no windows, just background+mouse. can't switch to VT. SKIP.

5325f8624093bb1ec30d581b4ff64218ceab99f9 -> when enabling 3d no windows, just background+mouse. can't switch to VT. SKIP.

646325a5efb3cf4157623d115d6d8fa36f0b357d -> when enabling 3d no windows, just background+mouse. can't switch to VT. SKIP.

e1a8852aa49b535a4fcec4eefda3fb7f8e57a5cc 2009-04-17 00:37:53 -> GOOD

65fe0c86ffcff99f9f09606d462bf3731ea0c308 2009-04-19 -> X crashes when turning on 3d. SKIP.

466c78c93538f2853449124c06274d538830cd5a 2009-04-22 -> ## black background but X freeze. counting BAD..

0e8c6e56e467864249dfa311be1eef4dfc381f2a 2009-05-16 19:03:46 -> GOOD

2f9189d538ac56bd241ccc8f8f82bc4fdd779aa6 2009-05-28 11:40:58 -> BAD

545e574cd9a2a659cd9a93879dff8884bd247558 2009-06-07 08:51:32 -> BAD

00a216fd1e4ea284df9df71128b0e496816cab4d -> BAD 2009-07-16 16:28:58

396b4043f085ec09a074447bbbb835c53aa82b7b 2009-06-20 00:36:50 -> BAD (and unrelated crash during use)

a6a11e1dc019ad54e0c4c9d1de46ca6ca48528c3 2009-07-10 19:01:04 -> BAD

c5c19919ce627b98d8aab4284da1694573bcccd4 2009-07-15 20:17:07 -> BAD

aa99a765c15392d06e3a33d4eda377c58bc6afec 2009-07-23 19:48:04 -> BAD

c4903ee27f29b39a493701d35b38941249117a54 2009-07-28 9:49:40 ->BAD

7f8f486b36dc42a3818546c704321320fcdbc94b 2009-08-07 18:35:55 -> BAD

aa2514d12d17189b2b6e9ffc51c7092fe35b309d ? 2009-08-18 23:18 -> BAD

0d7bed9f8973547b675c35c0083996e946d7cecb 2009-08-28 00:50:44 -> GOOD

(I didn't get all those commit MD5s from bisect. some I did, some I just picked myself in gitk because the one that bisect gave me didn't compile for X or Y reason so I tried to narrow the search myself. I also did several runs of bisect)

One thing that tends to be problematic for git bisect is commits from non-master branches which were merged to master. It's probably a good idea to start with testing only merge commits, until the problem is isolated between two consecutive merge commits and/or genuine master commits.

seems to be the same issue as in bug #24406, also this other ubuntu bug:
https://bugs.launchpad.net/ubuntu/+source/compiz/+bug/444139

also mentioned in that ubuntu forums thread:
http://ubuntuforums.org/showthread.php?t=1278410

I'll try reducing resolution, bit depth, virtual desktop size but I guess this bug can be marked duplicate of bug #24406.

what's interesting is that really, it works fine with older mesa, not new ones.

I use 1280x1024 resolution.

I can confirm that reducing my resolution from 1280x1024 to 1024x768, the desktop is not anymore black when desktop effects are activated.

So it appears to be a video memory exhaustion. It seems mesa requires more video memory than it used to.

According to the forums and bugs that I linked it seems that enabling KMS fixes it as well (maybe when enabling KMS less video memory is needed for some reason?).

well besides video memory exhaustion it could also be some max texture size hit somewhere I guess.

Note that in the other bug people say that enabling KMS makes the problem go away.

Emmanuel Touzery, Ubuntu Karmic reached EOL on April 30, 2011. For more on this, please see https://wiki.ubuntu.com/Releases .

If this is reproducible in a supported release, it will help immensely if you filed a new report with Ubuntu by ensuring you have the package xdiagnose installed, and that you click the Yes button for attaching additional debugging information running the following from a terminal:
ubuntu-bug xorg

Also, please feel free to subscribe me to it.

For more on why this is helpful, please see https://wiki.ubuntu.com/ReportingBugs.