28 August 2007 by Lars
X11, modelines, and new monitors
I finally figured out the correct way, regardless of Linux distribution tools, on how to configure an unknown/new monitor. It turns out that Xorg will use I2C tools to query the monitor. Among other things, the monitor will report sync rates, size, age, name, etc. Most importantly, it will report all that is needed to write a new modeline in xorg.conf:
(II) MGA(0): Supported additional Video Mode: (II) MGA(0): clock: 146.2 MHz Image Size: 473 x 296 mm (II) MGA(0): h_active: 1680 h_sync: 1784 h_sync_end 1960 h_blank_end 2240 h_border: 0 (II) MGA(0): v_active: 1050 v_sync: 1053 v_sync_end 1059 v_blanking: 1089 v_border: 0 (II) MGA(0): Ranges: V min: 56 V max: 75 Hz, H min: 30 H max: 83 kHz, PixClock max 150 MHz
We can take this information, and create the monitor and mode sections in the xorg.conf file:
Section "Monitor" Identifier "Monitor[0]" UseModes "Modes[0x]" ModelName "E228WFP (ANALOG)" VendorName "DELL" DisplaySize 473 296 Option "DPMS" HorizSync 30-83 VertRefresh 56-75 EndSection
and
Section "Modes" Identifier "Modes[0x]" Modeline "1680x1050" 146.20 1680 1784 1960 2240 1050 1053 1059 1089 EndSection
If you want to second-guess the monitor, you can always go to the XFree86 Modeline Generator to tweak it.
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