[intel] problems with ddc monitor detection.

Marcos Dione mdione at except.com.ar
Wed Apr 23 08:44:55 PDT 2008


    hi all. first of all, cc: me when answering, as I'm not suscribed to
the list.

    I've bought a couple of intel d495gcpe motherboards, which came with
the integrated Intel 82945 video card. those are attached to matching
samsung syncmaster 943nwx 19' widescreen lcd's. both are using ubuntu
7.04 feisty, which has the inter driver version 1.9.94-1ubuntu5. both
mother boards have the same bios.

    the problem is that on of the machines detects correctly the monitor
and outputs the asked resolution of 1440x900, which is the native
resolution of these lcd's. the other one fails to do so and outputs a
4:3 resolution, which is no good with this lcd's.

    I determined that the only difference between these two is that the
second, failing one seemd to not support ddc2 transfers. here are the
relevant snips of output from get-edid in both machines:

working one:
        Monitor and video card combination does not support DDC1 transfers
        Monitor and video card combination supports DDC2 transfers

failing one:
        Monitor and video card combination does not support DDC1 transfers
        Monitor and video card combination does not support DDC2 transfers

    is not a monitor or cable problem, as I used the ones in the other
machine to rule that out.

    as ddc fails, I tried to force the resolution, even disabling ddc
detection via the ddc option of the intel driver, but it fails. I also
tried using 915resolution, but no fun. I built a modeline in the other
machine and used that, but the resolution gets discarded because it
exceeds the horizontal freq, even if I put a range ridicously big
(10-200).

    let alone that the motherboard mus be defective in some way (maybe
the ddc line is broken, but I can't make my provider replace the mobo),
is there any other way to make the board output the desired resolution
(1440x900) irrespective of what's attached to it? 

    please, remember to cc: me any answers. saludos, 

	Marcos.

-- 
        Marcos Dione |           |/_
    [ 浪人 - ronin ] |         .(_)
mdione at except.com.ar | http://except.com.ar/



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