Emc vs modern lcd monitors

Alex Deucher alexdeucher at gmail.com
Mon Aug 15 14:09:46 PDT 2011

2011/8/15 gene heskett <gheskett at wdtv.com>:
> On Monday, August 15, 2011 04:20:49 PM Mark Wagner did opine:
>> On Sat, Aug 13, 2011 at 05:50, gene heskett <gheskett at wdtv.com> wrote:
>> > Greetings all;
>> >
>> > One of the problems that was confusing me recently is that I had
>> > replaced the old samsung crt monitor with a much newer cheap AOC lcd
>> > that runs at 1360x724 at best, but under the vesa driver on an ati
>> > x1650 video card, it apparently is running in 1024x768. آ This
>> > results in a pixel that is far from square unless I use a button on
>> > the monitor which shrinks the display sideways, leaving 2" wide black
>> > stripes on the sides.
>> >
>> > From Xorg.0.log:
>> >
>> > (II) VESA(0): SAMSUNG: Using hsync range of 30.00-81.00 kHz
>> > (II) VESA(0): SAMSUNG: Using vrefresh range of 55.00-75.00 Hz
>> > (II) VESA(0): SAMSUNG: Using maximum pixel clock of 90.00 MHz
>> > (II) VESA(0): Not using mode "1360x768" (no mode of this name)
>> > <---native
>> Looks to me like the server is telling you it doesn't know how to
>> generate a resolution of 1360x768.  If this was a CRT, I'd say to
>> provide a custom modeline in the xorg.conf file.  Since you've got a
>> LCD, I don't know if this is the correct solution or not.
> None of my machines have an xorg.conf with a sample modeline for that.
> Could someone post an example I could try please?
> Or even better, are there docs someplace that would describe how to do
> that?  I just looked at the modeline description in a man xorg.conf, and
> that lacks the specifics I'd need to make a quasi-intelligent first guess.

The problem with vesa is that you are limited to standard vesa modes
that are implemented in the vbios.  You cannot define arbitrary modes.
 For that you need to use a real driver specific to your video chip.


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