Bug#766786: To avoid the artefacts produced by using bugreporter

[Graeme Vetterlein]

I'll attach the original test file I created and attempted to move to 
the wheezy box, in groups of 4-5 lines:

--

Graeme
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root at vjessie:/mnt# uname -a
Linux vjessie 3.16-2-amd64 #1 SMP Debian 3.16.3-2 (2014-09-20) x86_64 GNU/Linux

root at vjessie:/mnt# dpkg -l | grep xdm
ii  libxdmcp6:amd64         1:1.1.1-1        amd64            X11 Display Manager Control Protocol library
ii  xdm                     1:1.1.11-1       amd64            X display manager
root at vjessie:/mnt# dpkg -l | grep gdm
ii  gdm3                    3.14.0-1         amd64            GNOME Display Manager
ii  gir1.2-gdm3             3.14.0-1         amd64            GObject introspection data for the GNOME Display Ma
ii  libgdm1                 3.14.0-1         amd64            GNOME Display Manager (shared library)
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This is an issue with jessie but not wheezy.

XDMCP connections to Jessie+gdm3 fail after a few seconds, while Jessie+xdm work fine.


Environment:

real machine (DNS name= "real.home") runs Fedora20 , and qemu+kvm.

Virtual machines exist (e.g vdebain.home [wheezy] , vjessie.home )

Normal usage would be on "real.home" on another console (ALT-F3 etc) start:

       X :2 -query 10.116.1.53     (address of vjessie)

If vjessie is running xdm , this works fine. If vjessie runs gdm3 it works for
about a minute, then just keeps dropping back to black X sreen (with X cursor)

SETUP:

On jessie:

   install xdm, choose xdm as the default display manger.
   Edit /etc/X11/xdm/xdm.config: (comment out the disable requestPort]

! Comment out this line if you want to manage X terminals with xdm
! GPV (previously was NOT commented) DisplayManager.requestPort:	0

*restart"

root at vjessie:/etc/X11/xdm# lsof -i:177
COMMAND PID USER   FD   TYPE DEVICE SIZE/OFF NODE NAME
xdm     906 root    4u  IPv6   1923      0t0  UDP *:xdmcp 

From "real.home" :

ALT-F3

	X :2 -query vjessie.home

On ALT-F1, a xmd logon screen appears. 
After giving userid+password, a jessie screen (need to authenticate to manage color managed console)
pops up and requires a passsword [ this is new and does not happen in wheezy ] after authenticating
a normal desktop appears and works fine.

On jessie, do:

   dpkg-reconfigure xdm

And choose gmd3

    	   start-stop-daemon: pid value must be a number greater than 0
	   Try 'start-stop-daemon --help' for more information.

*restart*

Get gdm3 logon, after giving password, you get prompted with jessie screen (need
to authenticate to manage color managed console) , after authenticating, you get a normal
jessie (gdm) desktop. Start an xterm and wait a minute or so. You get dropped back to a plain black
X terminal (cursor is big X).
...from this point on, after switching to another console (one real.home), about once a minute , it switches back to
ALT-F1 and the blank X terminal. This pattern repeats.


In vjessie:/var/log/messages: there are messages about "out of video memory" (which may well relate to what is happening)


Oct 25 18:33:53 vjessie gdm-Xorg-:0[3495]: Out of video memory: Could not allocate 4378332 bytes
Oct 25 18:33:53 vjessie gdm-Xorg-:0[3495]: - 0th attempt
Oct 25 18:33:53 vjessie gdm-Xorg-:0[3495]: - OOM at 1109 986 24 (= 3280422 bytes)
Oct 25 18:33:53 vjessie gdm-Xorg-:0[3495]: Cache contents:  null null null null null null null null null null null null null null null null null null null null null null null null null null null null null null null null null null null null null null null null null null null null null null null null  339  333  330  350  338  343  336  355 1015  354  739  976 1016  977 1011 1003     total: 16
Oct 25 18:33:53 vjessie gdm-Xorg-:0[3495]: Out of video memory: Could not allocate 4378332 bytes
Oct 25 18:33:57 vjessie gdm-Xorg-:0[3495]: qxl_surface_create: Bad bpp: 1 (1)
Oct 25 18:34:22 vjessie gdm-Xorg-:0[3495]: qxl_surface_create: Bad bpp: 1 (1)
Oct 25 18:34:38 vjessie gdm-Xorg-:0[3495]: qxl_surface_create: Bad bpp: 1 (1)


But **NOTE** these messages are on vjessie.home. This is an XDMCP type login, so the Xterminal is on "real.home" where there are NO
messages. The virtual machine (vjessie) had a QXL display with 64Mb ... note qxl_surface in the above message.
I wonder if gdm is attepting to use the wrong display?

Using gmd3 via SPICE, seems to work fine (wheezy was very poor in this mode)
but it is something like 100 times faster using XDMCP.