Can't change resolution: “xrandr: Configure crtc 0 failed”

Question

I connect to a Ubuntu host using TeamViewer. It's resolution is currently 800x600. I would like to change it's resolution to 1024x768, but I get this error:

xrandr: Configure crtc 0 failed

The command was:

xrandr --output Virtual1 --mode 1024x768

I've searched for a solution, but I haven't found any.

The result for xrandr --verbose is:

Screen 0: minimum 1 x 1, current 800 x 600, maximum 8192 x 8192
Virtual1 connected primary 800x600+0+0 (0x4f) normal (normal left inverted right x axis y axis) 0mm x 0mm
    Identifier: 0x47
    Timestamp:  351902893
    Subpixel:   horizontal rgb
    Gamma:      1.0:1.0:1.0
    Brightness: 1.0
    Clones:    
    CRTC:       0
    CRTCs:      0
    Transform:  1.000000 0.000000 0.000000
                0.000000 1.000000 0.000000
                0.000000 0.000000 1.000000
               filter: 
  800x600 (0x4f) 42.750MHz -HSync +VSync *current +preferred
        h: width   800 start  850 end  900 total  950 skew    0 clock  45.00KHz
        v: height  600 start  650 end  700 total  750           clock  60.00Hz
  1360x768 (0x50) 85.500MHz +HSync +VSync
        h: width  1360 start 1424 end 1536 total 1792 skew    0 clock  47.71KHz
        v: height  768 start  771 end  777 total  795           clock  60.02Hz
  1280x800 (0x51) 83.500MHz +HSync -VSync
        h: width  1280 start 1352 end 1480 total 1680 skew    0 clock  49.70KHz
        v: height  800 start  803 end  809 total  831           clock  59.81Hz
  1152x864 (0x52) 108.000MHz +HSync +VSync
        h: width  1152 start 1216 end 1344 total 1600 skew    0 clock  67.50KHz
        v: height  864 start  865 end  868 total  900           clock  75.00Hz
  1280x768 (0x53) 79.500MHz -HSync +VSync
        h: width  1280 start 1344 end 1472 total 1664 skew    0 clock  47.78KHz
        v: height  768 start  771 end  778 total  798           clock  59.87Hz
  1024x768 (0x54) 65.000MHz -HSync -VSync
        h: width  1024 start 1048 end 1184 total 1344 skew    0 clock  48.36KHz
        v: height  768 start  771 end  777 total  806           clock  60.00Hz
  800x600 (0x55) 40.000MHz +HSync +VSync
        h: width   800 start  840 end  968 total 1056 skew    0 clock  37.88KHz
        v: height  600 start  601 end  605 total  628           clock  60.32Hz
  640x480 (0x56) 25.175MHz -HSync -VSync
        h: width   640 start  656 end  752 total  800 skew    0 clock  31.47KHz
        v: height  480 start  489 end  492 total  525           clock  59.94Hz
Virtual2 disconnected (normal left inverted right x axis y axis)
    Identifier: 0x48
    Timestamp:  351902893
    Subpixel:   horizontal rgb
    Clones:    
    CRTCs:      1
    Transform:  1.000000 0.000000 0.000000
                0.000000 1.000000 0.000000
                0.000000 0.000000 1.000000
               filter: 
Virtual3 disconnected (normal left inverted right x axis y axis)
    Identifier: 0x49
    Timestamp:  351902893
    Subpixel:   horizontal rgb
    Clones:    
    CRTCs:      2
    Transform:  1.000000 0.000000 0.000000
                0.000000 1.000000 0.000000
                0.000000 0.000000 1.000000
               filter: 
Virtual4 disconnected (normal left inverted right x axis y axis)
    Identifier: 0x4a
    Timestamp:  351902893
    Subpixel:   horizontal rgb
    Clones:    
    CRTCs:      3
    Transform:  1.000000 0.000000 0.000000
                0.000000 1.000000 0.000000
                0.000000 0.000000 1.000000
               filter: 
Virtual5 disconnected (normal left inverted right x axis y axis)
    Identifier: 0x4b
    Timestamp:  351902893
    Subpixel:   horizontal rgb
    Clones:    
    CRTCs:      4
    Transform:  1.000000 0.000000 0.000000
                0.000000 1.000000 0.000000
                0.000000 0.000000 1.000000
               filter: 
Virtual6 disconnected (normal left inverted right x axis y axis)
    Identifier: 0x4c
    Timestamp:  351902893
    Subpixel:   horizontal rgb
    Clones:    
    CRTCs:      5
    Transform:  1.000000 0.000000 0.000000
                0.000000 1.000000 0.000000
                0.000000 0.000000 1.000000
               filter: 
Virtual7 disconnected (normal left inverted right x axis y axis)
    Identifier: 0x4d
    Timestamp:  351902893
    Subpixel:   horizontal rgb
    Clones:    
    CRTCs:      6
    Transform:  1.000000 0.000000 0.000000
                0.000000 1.000000 0.000000
                0.000000 0.000000 1.000000
               filter: 
Virtual8 disconnected (normal left inverted right x axis y axis)
    Identifier: 0x4e
    Timestamp:  351902893
    Subpixel:   horizontal rgb
    Clones:    
    CRTCs:      7
    Transform:  1.000000 0.000000 0.000000
                0.000000 1.000000 0.000000
                0.000000 0.000000 1.000000
               filter: 

It seems, that the 1024x768 resolution is supported. Why isn't it available?

I've tried arandr too, but it gives the same error.

The other resolutions are also not working, only 800x600

---

The result for xtrace xrandr --output Virtual1 --mode 1024x768 is uploaded: http://pastebin.com/AVnbDtQa

If I run xrandr --fb 1024x768 then the it gets pixelerated, and some parts does not fit into the screen.

If I run X -configure I get this error:

(EE) 
Fatal server error:
(EE) Server is already active for display 0
    If this server is no longer running, remove /tmp/.X0-lock
    and start again.
(EE) 
(EE) 
Please consult the The X.Org Foundation support 
     at http://wiki.x.org
 for help. 
(EE) 

I would like to avoid rebooting, if possible.

---

The result for xrandr -d :0 is:

Screen 0: minimum 1 x 1, current 800 x 600, maximum 8192 x 8192
Virtual1 connected primary 800x600+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
   800x600       60.00*+  60.32  
   1360x768      60.02  
   1280x800      59.81  
   1152x864      75.00  
   1280x768      59.87  
   1024x768      60.00  
   640x480       59.94  
Virtual2 disconnected (normal left inverted right x axis y axis)
Virtual3 disconnected (normal left inverted right x axis y axis)
Virtual4 disconnected (normal left inverted right x axis y axis)
Virtual5 disconnected (normal left inverted right x axis y axis)
Virtual6 disconnected (normal left inverted right x axis y axis)
Virtual7 disconnected (normal left inverted right x axis y axis)
Virtual8 disconnected (normal left inverted right x axis y axis)