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Martin Hope
Toto
Asked: 2010-10-22 07:01:20 +0800 CST
  • 3

I've experiences some configuration "resets" after ubuntu crashes:

  • Display configuration changed (I'd changing through /usr/bin/nvidia-settings)
  • Hibernation/Suspension turned on again (I'd disabled it)

In order to prevent those, I would like to know how exactly ubuntu recovers from crashes.

Background: I'm particulary intereseted in this topic because I've ubuntu connected to displays showing information across a public building. And it's pretty embarassing when the display config is all messed up and sometimes going all black (resolution not supported).

10.04 configuration
Martin Hope
Toto
Asked: 2010-10-08 09:34:44 +0800 CST
  • 3

I tried to change the resolution using the following commands (found here):

Use xrandr to check the current configuration and available modes:

$ xrandr
Screen 0: minimum 64 x 64, current 800 x 600, maximum 32000 x 32000
VBOX1 connected 800x600+0+0 0mm x 0mm
   800x600        60.0*+
   640x480        59.9

Use cvt to get the proper modeline for 1280x800:

$ cvt 1280 800
# 1280x800 59.81 Hz (CVT 1.02MA) hsync: 49.70 kHz; pclk: 83.50 MHz
Modeline "1280x800_60.00"   83.50  1280 1352 1480 1680  800 803 809 831 -hsync +vsync

Create the new mode using xrandr --newmode:

$ xrandr --newmode "1280x800_60.00"   83.50  1280 1352 1480 1680  800 803 809 831 -hsync +vsync

Use xrandr again to check that the mode was created successfully:

$ xrandr
Screen 0: minimum 64 x 64, current 800 x 600, maximum 32000 x 32000
VBOX1 connected 800x600+0+0 0mm x 0mm
   800x600        60.0*+
   640x480        59.9  
  1280x800_60.00 (0x11a)   83.0MHz
        h: width  1280 start 1352 end 1480 total 1680 skew    0 clock   49.4KHz
        v: height  800 start  803 end  809 total  831           clock   59.5Hz

However, when I try to add the new mode to the display with xrandr --addmode I get the following error:

$ xrandr --addmode VBOX1 1280x800_60.00
X Error of failed request:  BadMatch (invalid parameter attributes)
  Major opcode of failed request:  150 (RANDR)
  Minor opcode of failed request:  18 (RRAddOutputMode)
  Serial number of failed request:  18
  Current serial number in output stream:  19

Of course, if I try to set the new resolution for my current display it fails (the mode isn't associated to te display):

$ xrandr --output VBOX1 --mode 1280x800_60.00
xrandr: cannot find mode 1280x800_60.00
10.04 configuration xrandr
Martin Hope
Toto
Asked: 2010-10-07 07:05:07 +0800 CST
  • 3

Hardware

I have the following hardware configuration:

  • PC running Ubuntu 10.04
  • Onboard video card with one VGA output (Intel P4M800 - Via Unichrome)
  • VGA splitter: 1 input, 4 outputs. Up to 2048x1536 (according to spec)
  • One 42'' TV/Monitor connected to the splitter via its VGA input
  • Two 32'' TV/Monitor connected to the splitter via its VGA input

Problem

With that configuration, Ubuntu only shows 640x480 and 800x800 as possible resolutions. However, if I connect any of the TV/Monitor directly to the PC (via VGA) then Ubuntu shows a long list of possible resolution (I tried several of them and they worked fine).

It seems that X Window System automatic configuration is not working properly. How do I manually configure it? What info should knows of the different devices involved beforehand?

Context: The monitors are intalled in public spaces across one building to display dynamic information that is processed in the PC (a Flash presentation running in Firefox in fullscreen mode).

Update:

I tried the following, as the link provided in the answers said:

  1. Get the modeline for the resolution using cvt

  2. Created the new mode using xrandr --newmode

  3. Added the mode to the output display using xrandr --addmode

  4. Tried to change the resolution using xrandr --output ... --mode ...

But I get this: xrandr screen cannot be larger than 800x600 (desired size ...)

xorg video display