[RESOLVED] Can't select native resolution of 1366x768 monitor

[Mountain Man]

I'm trying to configure a monitor with a native resolution of 1366x768, but Kubuntu is insisting on setting it to 1368x768. I can't even get it to recognize the correct resolution from the command line:

$ cvt 1366 768
# 1368x768 59.88 Hz (CVT) hsync: 47.79 kHz; pclk: 85.25 MHz
Modeline "1368x768_60.00"  85.25 1368 1440 1576 1784 768 771 781 798 -hsync +vsync

I've tried setting things manually in xorg.conf but no joy. No matter what I do, the KDE screen size and rotate tool and NVIDIA X Server Settings won't give me the option for 1366x768.

The monitor is a ViewSonic VA1931wa-LED.

Any suggestions?

[Snowhog]

Re: Can't select native resolution of monitor

Open a console and type:

xrandr

invoked without any option, it will dump the state of the outputs,
showing the existing modes for each of them, with a '+' after the pre‐
ferred mode and a '*' after the current mode.

Then type:

man xrandr

and review for the options to set your screen size.

[Mountain Man]

Re: Can't select native resolution of monitor

O.K., here's the problem, 1366x768 isn't listed as one of the modes:

$ xrandr
xrandr: Failed to get size of gamma for output default
Screen 0: minimum 320 x 240, current 1368 x 768, maximum 1368 x 768
default connected 1368x768+0+0 0mm x 0mm
  1368x768    50.0* 
  1360x768    51.0   52.0 
  1024x768    53.0   54.0   55.0 
  960x600    56.0 
  960x540    57.0 
  840x525    58.0   59.0   60.0   61.0 
  832x624    62.0 
  800x600    63.0   64.0   65.0   66.0   67.0   68.0 
  800x512    69.0 
  720x450    70.0 
  680x384    71.0   72.0 
  640x512    73.0   74.0 
  640x480    75.0   76.0   77.0   78.0   79.0   80.0 
  576x432    81.0   82.0   83.0   84.0 
  512x384    85.0   86.0   87.0 
  416x312    88.0 
  400x300    89.0   90.0   91.0   92.0 
  320x240    93.0   94.0   95.0

Okay, simple enough, I just add a new mode, right? Nope. When I run cvt to get the modeline value, it changes the horizontal resolution:

$ cvt 1366 768
# 1368x768 59.88 Hz (CVT) hsync: 47.79 kHz; pclk: 85.25 MHz
Modeline "1368x768_60.00"  85.25 1368 1440 1576 1784 768 771 781 798 -hsync +vsync

So where do I get the correct values for the modeline, and why won't simply setting things in xorg.conf work?

Here's what I have in xorg.conf:

Section "Module"
  Load      "glx"
EndSection

Section "Monitor"
  Identifier   "Monitor0"
  VendorName   "ViewSonic"
  ModelName   "VA1931wa-LED"
  HorizSync    24.0 - 82.0
  VertRefresh   50.0 - 75.0
EndSection

Section "Device"
  Identifier   "Device0"
  Driver     "nvidia"
  VendorName   "NVIDIA Corporation"
  BoardName   "GeForce 7800 GS"
  Option     "NoLogo"	"True"
EndSection

Section "Screen"
  Identifier   "Screen0"
  Device     "Device0"
  Monitor    "Monitor0"
  DefaultDepth  24
  SubSection   "Display"
    Depth    24
    Modes   "1366x768"
  EndSubSection
EndSection

[Snowhog]

Re: Can't select native resolution of monitor

Read this: 1080i on 1366x768 resolution problems

1366 x 768 is not a broadcast standard in any way shape or form.

Standard EDID codes dont exist for 1366 x 768 resolution ...

I don't think you are going to get Linux to recognize/accept the 1366x768 resolution. :P

[Mountain Man]

Re: Can't select native resolution of monitor

I don't think you are going to get Linux to recognize/accept the 1366x768 resolution. :P

Well crap.

Thanks for your help.

Edit: Based on the article you posted, it suggested that a 1366x768 monitor could cleanly display a 1280x768 image, so I set things to that resolution, and apparently it can. Good enough.

Here's my final xorg.conf that seems to be working out well in case it helps anybody in the future:

# nvidia-settings: X configuration file generated by nvidia-settings
# nvidia-settings: version 270.29 (buildd@roseapple) Fri Feb 25 14:43:24 UTC 2011

Section "Module"
  Load      "glx"
EndSection

Section "Monitor"
  # HorizSync source: edid, VertRefresh source: edid
  Identifier   "Monitor0"
  VendorName   "Unknown"
  ModelName   "ViewSonic VA1931 Series"
  HorizSync    24.0 - 82.0
  VertRefresh   50.0 - 75.0
  ModeLine    "1280x768_60.00" 79.500 1280 1344 1472 1664 768 771 781 798 -hsync +vsync
  Option     "DPMS"
EndSection

Section "Device"
  Identifier   "Device0"
  Driver     "nvidia"
  VendorName   "NVIDIA Corporation"
  BoardName   "GeForce 7800 GS"
  Option     "NoLogo" "True"
EndSection

Section "Screen"
  Identifier   "Screen0"
  Device     "Device0"
  Monitor    "Monitor0"
  DefaultDepth  24
  Option     "TwinView" "0"
  Option     "TwinViewXineramaInfoOrder" "CRT-0"
  Option     "metamodes" "1280x768_60 +0+0"
  SubSection   "Display"
    Depth    24
  EndSubSection
EndSection

[Guest]

A resolution of 1366x768 can be made to work by copy-pasting the following into /etc/X11/xorg.conf:

Section "ServerLayout"
    Identifier     "Layout0"
    Screen      0  "Screen0" 0 0
    InputDevice    "Keyboard0" "CoreKeyboard"
    InputDevice    "Mouse0" "CorePointer"
    Option         "Xinerama" "0"
EndSection

Section "Files"
EndSection

Section "InputDevice"

    # generated from default
    Identifier     "Mouse0"
    Driver         "mouse"
    Option         "Protocol" "auto"
    Option         "Device" "/dev/psaux"
    Option         "Emulate3Buttons" "no"
    Option         "ZAxisMapping" "4 5"
EndSection

Section "InputDevice"

    # generated from default
    Identifier     "Keyboard0"
    Driver         "kbd"
EndSection

Section "Monitor"
    Identifier     "Monitor0"
    VendorName     "Unknown"
    ModelName      "DFP-0"
    HorizSync       28.0 - 67.0
    VertRefresh     50.0 - 75.0
    ModeLine       "1366x768" 85.50 1366 1440 1584 1792 768 771 777 795 +hsync +vsync
    Option         "DPMS"
EndSection

Section "Device"
    Identifier     "Device0"
    Driver         "nvidia"
    VendorName     "NVIDIA Corporation"
    BoardName      "ION"
EndSection

Section "Screen"
    Identifier     "Screen0"
    Device         "Device0"
    Monitor        "Monitor0"
    DefaultDepth    24
    Option         "UseEdidDpi" "FALSE"
    Option         "ModeDebug" "true"
#    Option         "ExactModeTimingsDVI" "true"
#    Option         "ModeValidation" "NoWidthAlignmentCheck, NoDFPNativeResolutionCheck"
#    Option "ModeValidation"    "AllowInterlacecModes, NoTotalSizeCheck,AllowNon60HzDFPModes,NoEdidMaxPClkCheck,NoVertRefreshCheck,NoHorizSyncCheck,NoDFPNativeResolutionCheck,NoVesaModes,NoEdidModes,NoXServerModes,NoPredefinedModes,NoMaxSizeCheck,NoVirtualSizeCheck,NoMaxPclkCheck,NoVertRefreshCheck"
    Option         "ModeValidation" "NoWidthAlignmentCheck, NoDFPNativeResolutionCheck, NoVesaModes, NoEdidModes, NoXServerModes, AllowNonEdidModes, NoPredefinedModes"
#    Option         "UseEDID" "False"
    Option         "TwinView" "0"
    Option         "metamodes" "1366x768 +0+0"
    SubSection     "Display"
        Depth       24
    EndSubSection
EndSection