screen size wrong while using kvm switch

Bug #238263 reported by Mike P.
This bug report is a duplicate of:  Bug #213895: Ubuntu failes to work with KVM switch. Edit Remove
8
Affects Status Importance Assigned to Milestone
xorg (Ubuntu)
Won't Fix
Undecided
Unassigned

Bug Description

Screen size wrong while using KVM switch in 8.04.
Used same hardware with 7.10 with no problems.
Sees nvidia card correctly and lists plug and play Westinghouse 19" monitor at the correct resolution of 1400 x 900, but the desktop is much bigger than the actual screen. Works correctly connecting monitor directly to the box.
Mandriva doesn't have this problem, so it seems like a Kubuntu issue.
Doesn't matter if I use nvidia's driver or not.
Also works correctly using the KVM switch when booted from the live cd.
Amd 939 4000+
nvidia 7300 256mb
1gb ram
linkskey 4 port kvm model LKV-S04ASK

Thanks,
Mike P.

Revision history for this message
SD (sfdawson) wrote :

Any work arounds for this bug? I'm getting it as well using a Dell 19" LCD.

Revision history for this message
Mike P. (mp2beach) wrote :

It seems I have gotten mine to work again by not only cold starting the box, but by cold starting the monitor and switch at the same time. It almost sounds silly, but everything is working fine now - when before nothing else worked.

Mike P.

Revision history for this message
Dereck Wonnacott (dereck) wrote :

Thank you for taking the time to report this bug and helping to make Ubuntu better. Could you include the following information please? Then set the bug status to 'new' to signify that it is ready for triage / review.

Resolution, rate, or other parameter expected
Resolutions, rates, or other parameters actually obtained

/etc/X11/xorg.conf
/var/log/Xorg.0.log
output of sudo ddcprobe
output of xrandr

Changed in xorg:
status: New → Incomplete
Revision history for this message
Mike P. (mp2beach) wrote :
Download full text (27.2 KiB)

As I said, things seem to be working, but the times I have timed out on the log-on screen the problem re-appears till I reboot.
Before everything seemed to be listed properly with the right nvidia video driver and screen resolution (1440x900), but looked like it was 640x480
After many hours over many days and many cold and warm boots later, I sorta gave up. Several days after that I boot up and EVERYTHING WORKED!
Still don't know why.

Here is the info requested:

/etc/X11/xorg.conf
/var/log/Xorg.0.log
output of sudo ddcprobe
output of xrandr

 xorg.conf

# xorg.conf (X.Org X Window System server configuration file)
#
# This file was generated by dexconf, the Debian X Configuration tool, using
# values from the debconf database.
#
# Edit this file with caution, and see the xorg.conf manual page.
# (Type "man xorg.conf" at the shell prompt.)
#
# This file is automatically updated on xserver-xorg package upgrades *only*
# if it has not been modified since the last upgrade of the xserver-xorg
# package.
#
# If you have edited this file but would like it to be automatically updated
# again, run the following command:
# sudo dpkg-reconfigure -phigh xserver-xorg

Section "InputDevice"
 Identifier "Generic Keyboard"
 Driver "kbd"
 Option "XkbRules" "xorg"
 Option "XkbModel" "pc105"
 Option "XkbLayout" "us"
EndSection

Section "InputDevice"
 Identifier "Configured Mouse"
 Driver "mouse"
 Option "CorePointer"
EndSection

Section "Device"
 Identifier "Configured Video Device"
 Driver "nvidia"
 Option "NoLogo" "True"
EndSection

Section "Monitor"
 Identifier "Configured Monitor"
EndSection

Section "Screen"
 Identifier "Default Screen"
 Monitor "Configured Monitor"
 Device "Configured Video Device"
 Defaultdepth 24
EndSection

Section "ServerLayout"
 Identifier "Default Layout"
  screen "Default Screen"
EndSection
Section "Module"
 Load "glx"
EndSection

/var/log/Xorg.0.log

X.Org X Server 1.4.0.90
Release Date: 5 September 2007
X Protocol Version 11, Revision 0
Build Operating System: Linux Ubuntu (xorg-server 2:1.4.1~git20080131-1ubuntu9.2)
Current Operating System: Linux kubuntu 2.6.24-19-generic #1 SMP Wed Jun 18 14:15:37 UTC 2008 x86_64
Build Date: 13 June 2008 01:10:57AM

 Before reporting problems, check http://wiki.x.org
 to make sure that you have the latest version.
Module Loader present
Markers: (--) probed, (**) from config file, (==) default setting,
 (++) from command line, (!!) notice, (II) informational,
 (WW) warning, (EE) error, (NI) not implemented, (??) unknown.
(==) Log file: "/var/log/Xorg.0.log", Time: Sun Jul 6 16:23:15 2008
(==) Using config file: "/etc/X11/xorg.conf"
(==) ServerLayout "Default Layout"
(**) |-->Screen "Default Screen" (0)
(**) | |-->Monitor "Configured Monitor"
(**) | |-->Device "Configured Video Device"
(==) Automatically adding devices
(==) Automatically enabling devices
(==) No FontPath specified. Using compiled-in default.
(WW) The directory "/usr/share/fonts/X11/cyrillic" does not exist.
 Entry deleted from font path.
(==) FontPath set to:
 /usr/share/fonts/X11/misc,
 /usr/share/fonts/X11/100dpi/:unscaled,
 /usr/share/fonts/X11/75dpi/:unscaled,
 /usr/share/fonts/X11/Type1,
 /usr/sha...

Revision history for this message
AlanQ (alan-q) wrote :

I think I might be able to shed some more light on this issue.

I have only noticed this problem in the last few days.
First on a machine running 8.04, then on a machine running 7.04 (I'm guessing because some part of X.org in 7.04 has recently been updated via Update Manager).

See also:
http://ubuntuforums.org/archive/index.php/t-437194.html
http://ubuntuforums.org/showthread.php?t=846128
https://help.ubuntu.com/community/XORGHardy
The first two describe a similar problem. The third may describe part of the cause.

Earlier versions of X.org would create the /etc/xorg.conf file during installation.
This is fine until you change some of your video hardware.
Later versions of X.org now use 'dynamic recognition' of video hardware during boot.
Of course, if the machine is connected via a KVM switch and does not have 'sight' of the monitor during boot, X.org will default to 'safe' settings.
My assumption is that, prior to the very latest version, X.org would fall back on the xorg.conf file if it couldn't see the monitor.
Perhaps the X.org guys decided that, not 'seeing' the monitor might mean that an old monitor had been plugged in. In which case, using the settings in xorg.conf could damage the monitor.
This, of course, doesn't help those of us simply using a KVM switch.

Short term solution (tested and working for me):
Give the booting machine focus via the KVM until it's up.

Revision history for this message
Dereck Wonnacott (dereck) wrote :
Revision history for this message
Dereck Wonnacott (dereck) wrote :
Revision history for this message
Dereck Wonnacott (dereck) wrote :
Revision history for this message
Dereck Wonnacott (dereck) wrote :
Revision history for this message
Dereck Wonnacott (dereck) wrote :

Seems to have the needed info to have some developer eyes.

Please use attachments rather than comments for outputs next time though. :) It makes it easier to read when dealing with many bugs a day. I have attached them for you this time.

Changed in xorg:
status: Incomplete → Confirmed
Revision history for this message
Timo Aaltonen (tjaalton) wrote :

There's nothing that can be done. KVM's don't store the EDID data so that the machines not being focused would know what resolution the monitor can handle. Closing the bug.

Changed in xorg:
status: Confirmed → Won't Fix
Revision history for this message
Wawrzyniec Niewodniczański (wawrzek) wrote :

There is quite easy (theoretical) resolution - allow user to specify edid information in config file.

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