This problem is probably pretty specific to my hardware, but I'm getting frustrated with my limited knowledge on things I might try to solve it, so I post it anyway and hope for help :)

I've got a new Samsung Series 9 Notebook (intel HD4000 graphic chip), and am running a pretty fresh Ubuntu 12.10 (dual boot with Windows 7) on it. Most things work fine except for my external monitor (Samsung SyncMaster). It is connected to my Notebook via an HDMI-D to VGA adapter (stupid combination, I know, but it's the only one I could find hardware for).

In /var/log/Xorg.0.log, I find for it probed modes with resolutions between 640x480 and 1280x1024, but not the one I want to use, which is 1920x1200. 1024x768 seems to be the only resolution in the EDID. I used cvt to get the modeline for 1920x1200. Output:

# 1920x1200 59.88 Hz (CVT 2.30MA) hsync: 74.56 kHz; pclk: 193.25 MHz
Modeline "1920x1200_60.00"  193.25  1920 2056 2256 2592  1200 1203 1209 1245 -hsync +vsync

If I feed xrandr with these values, my monitor changes to some resolution which doesn't even fill the full screen, and is skewed and flickering (even after using the screens auto-adjust). (The maximum dot clock frequency of my screen is 175 MHz, according to /var/log/Xorg.0.log).

I booted into Windows to get a better modeline from there, but it also didn't support other resolutions than the ones between 640x480 and 1280x1024. I connected my screen to my old laptop where it used to be working (nvidia graphic card, no adapter nedded, VGA to VGA) and got modelines there with cvt (same output as above), and under Windows -- output:

"1920x1200" 153,900 1920 1968 2000 2080 1200 1203 1209 1235 +hsync -vsync

This modeline works better than the cvt one, and after some auto-adjustement of the monitor one can almost manage to fit it to the actual size of the screen, but the display is very blurry (barely sharp enough to read text).

Using modeline generators from the web with the data from my monitor gives things like

Modeline "1920x1200@60i" 87.66 1920 1952 2280 2312 1200 1227 1233 1261 interlace

which don't even lead to output.

Has anybody experienced similar problems, or has an idea what to do? I really need an external screen for my work, and would greatly appreciate any hints...

1 Answer 1


For Samsung Syncmaster S24B750

Source: https://www.mythtv.org/wiki/Modeline_Database and http://www.samsung.com/us/support/owners/product/LS24B750VSG/ZA (manual)

Section "Monitor"
    Identifier  "SAMSUNG"
    HorizSync   20-200
    VertRefresh 30-120
    ModeLine "1920x1080@60" 148.50 1920 2008 2052 2200 1080 1084 1089 1125 +hsync +vsync

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