karmic gnome-display-properties hangs for external monitor mode 1280x1024

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This problem is affecting me as well, but I don't get a blank screen, but can only see the background image. The gnome panels disappear, and you can only use ALT-F2 to get a command window to change the settings.

Setting the screen res back to 1024x768 doesn't cure the problem, but setting the screens to mirrored and then back top this res does get the external monitor working again, and this is 100% reproducible.

I'm using the x86_64 bit version, so it would appear to be across the board.

More info
Machine Dell XPS1330
Graphics card:
00:02.0 VGA compatible controller: Intel Corporation Mobile GM965/GL960 Integrated Graphics Controller (rev 0c)
 Subsystem: Dell Device 0209
 Flags: bus master, fast devsel, latency 0, IRQ 30
 Memory at fea00000 (64-bit, non-prefetchable) [size=1M]
 Memory at e0000000 (64-bit, prefetchable) [size=256M]
 I/O ports at eff8 [size=8]

I have attached the .xsessions-error file which shows a compiz error.

As nick mentioned about compiz, I have tried:
    apt-get remove --purge compiz*

and then reboot the machine and then I used gnome-display-properties, this time it works! both 1280x1024 and 1024x768
so the problem must come from compiz.

So which process I should backtrace for you?

similar issues have been fixed recently do you still get the bug using compiz in karmic?

FYI I'm having the same bug with my Acer Aspire One D150. If I plug in the external monitor, hit "detect monitors", both screens goes black, and the netbook freezes. If I turn on the netbook with the external monitor plugged in, both monitors works mirrored, and at 800x600. If I try to change any monitor preference (like position or size), the netbook freezes.

I then tried disabling desktop effects (i.e. no compiz), and everything worked perfectly, at the maximun resolution (netbook at 1024x600, external LCD at 1680x1050)

HTH.

I'm also having the same problem on a asus eeepc 1000h with ubuntu 9.10 .

When connecting an external monitor the system freezes, not even when I remove the monitor again the system resumes. I have to restart the computer. If the monitor is attached to the eeepc when booting it is detected and used. The resolution on the eeepc lcd gets set to 640x480 though. If I try to change the resolution on the eeepc lcd the system hangs again.

Following the advice from supojc and nick and removing all compiz-related solved the problem.

Same here on Asus eeepc 1005HA on Ubuntu 9.10,

a solution is:
*) Connect VGA cable before login
*) If you're already logged in, connect VGA cable, logout an then login again

After that you can easily edit resolutions of your screens with gnome-display-properties, but compiz doesn't seem to work properly because my gnome-terminal has lost trasparency and mplayer shows white windows when playing video with "-vo xv",
I'm able to watch video only with "-vo x11" driver.

Note: removing VGA cable and restarting gdm solves all the problem related to compiz.

Hope that someone can fix this.

Bye.

OK seems that I can give you more informations on this bug.

If I disable compiz's effects using "Apperance" from Menu, I can make some test without having freeze using VGA:

NOTE: all the tests are not done in display cloning mode.

this is a normal output obtained from command "compiz --replace" without external monitor connected and/or enabled:

Checking for Xgl: not present.
xset q doesn't reveal the location of the log file. Using fallback /var/log/Xorg.0.log
Detected PCI ID for VGA:
Checking for texture_from_pixmap: present.
Checking for non power of two support: present.
Checking for Composite extension: present.
Checking screen 1Comparing resolution (1024x600) to maximum 3D texture size (2048): Passed.
Checking for Software Rasterizer: Not present.
Checking for nVidia: not present.
Checking for FBConfig: present.
running under gnome seesion, checking for gnomecompat
Checking for Xgl: not present.
Starting gtk-window-decorator

All gone ok, compiz works great without vga enabled.

This is the output of "compiz --replace" (disabling first Effects from Apperance's Menu) enabling VGA with "1280x1024" resolution:
Checking for Xgl: not present.
xset q doesn't reveal the location of the log file. Using fallback /var/log/Xorg.0.log
Detected PCI ID for VGA:
Checking for texture_from_pixmap: present.
Checking for non power of two support: present.
Checking for Composite extension: present.
Checking screen 1Comparing resolution (2304x1024) to maximum 3D texture size (2048): Failed.
aborting and using fallback: /usr/bin/metacity

As you can see there's a problem with resolution, the maximum 3D texture size appear to be: 2048 but I'm using 2304x1024 = 1024x600 (LVDS1) + 1280x1024 (VGA1)

Now it's ok no freeze because "compiz --replace" checks the maximum 3D texture size and reverts back to metacity.
That's another test, because I read from compiz output that the max 3D texture size is: 2048, before try to enable compiz effects I've manual set VGA1 resolution to "1024x768", this is the output of "compiz --replace":

Checking for Xgl: not present.
xset q doesn't reveal the location of the log file. Using fallback /var/log/Xorg.0.log
Detected PCI ID for VGA:
Checking for texture_from_pixmap: present.
Checking for non power of two support: present.
Checking for Composite extension: present.
Checking screen 1Comparing resolution (2048x768) to maximum 3D texture size (2048): Passed.
Checking for Software Rasterizer: Not present.
Checking for nVidia: not present.
Checking for FBConfig: present.
running under gnome seesion, checking for gnomecompat
Checking for Xgl: not present.
Starting gtk-window-decorator

As you can see all appear to be good but it's not true, screen freezes and I've to disconnect VGA and manually restart gdm.

This is my last test using "800x600" resolution for VGA1 before enabling Compiz's Effects:
Checking for Xgl: not present.
xset q doesn't reveal the location of the log file. Using fallback /var/log/Xorg.0.log
Detected PCI ID for VGA:
Checking for texture_from_pixmap: present.
Checking for non power of two support: present.
Checking for Composite extension: present.
Checking screen 1Comparing reso...

ok, searching launchpad and googling a lot,
I found this bug is an effect caused by bug: https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/438000
also reported into bug on freedesktop.org: http://bugs.freedesktop.org/show_bug.cgi?id=22076

As you can see the real problem is a bug/limitation on mesa-lib, you can avoid it by putting your external Monitor (VGA1) "below" your current screen (LDVS1),

NOTE: You've always "2048x2048 maximum 3D texture size" limitation so check if your vertical size will not overcome 2048, example: In my case vertical size is: 640 + 1024 = 1664 that doesn't overcome 2048 :-)

I've tested it and now it works great with compiz too,

this an example script that you can use to switch correctly on (without freeze) your external monitor:

#!/bin/bash

lvdsres="1024x600"
vgares="1280x1024"

if [ -e ~/.vgaconnected ]
then
xrandr --output VGA1 --off --output LVDS1 --mode $lvdsres && rm ~/.vgaconnected
else
xrandr --output LVDS1 --mode $lvdsres --output VGA1 --mode $vgares --rate 60 --below LVDS1 &> ~/.xrand.log && touch ~/.vgaconnected
fi

Let me know if this solution solved your problems too!

bye.

using an older thinkpad x40 and karmic and having this same problem. it seems Alessandro Arrichiello is correct and now i've got things working with compiz. the trick seems to be you have to settle for lowering the resolution so that neither width nor height sums to < 2048.

for example this won't work (except if screens stacked vertically):

vga1: 1024x768
lvds1: 1024x768

this will work no matter how screens are positioned:

vga1: 1024x768
lvds1: 800x600

i did not use the script above, i just made settings in System->Preferences->Display that followed the < 2048 rule.

excuse me while i revel in my dual screen awesome. :-)

Thank you for taking the time to report this bug and helping to make Ubuntu better. A new version of GNOME Control Center is available on Maverick and we are wondering if this bug is still an issue for you with that version? Could you please test and comment back? Thanks in advance.

We are closing this bug report because it lacks the information we need to investigate the problem, as described in the previous comments. Please reopen it if you can give us the missing information, and don't hesitate to submit bug reports in the future. To reopen the bug report you can click on the current status, under the Status column, and change the Status back to New. Thanks again!.

It has been fixed, thanks.