[PLUG] External monitor remains black

[John Jason Jordan]

In my peregrinations through the web I came across the possibility of
modifying the EDID in the monitor, as well as the possibility of adding
a line in xorg.conf to force the driver to read the EDID from a file.
The former can be done with a shareware tool called Powerstrip.
Unfortunately, it runs only on Windows, and I have no Windows on the
laptop. It is also scary.

As for getting the EDID into a file, I did that with a utility called
monitor-edid. Here is the ASCII version:

00 ff ff ff ff ff ff 00 24 4d 87 28 00 00 00 00 00 0f 01 03 80 21 15 78
0a bc a5 98 58 55 8b 28 24 50 54 00 00 00 01 01 01 01 01 01 01 01 01 01
01 01 01 01 01 01 1c 2f 90 d0 60 1a 0f 40 20 30 13 00 4b cf 10 00 00 19
45 27 90 d0 60 1a 0f 40 20 30 13 00 4b cf 10 00 00 19 00 00 00 0f 00 b3
0a 32 b3 0a 28 14 01 00 32 0c 00 00 00 00 00 fe 00 4c 50 31 35 34 57 30
32 2d 54 4c 30 36 00 bf 

Not very helpful, eh?

I can get the physical properties of the laptop display with xrandr (I
think). But I don't know how to put them into a file that the nVidia
driver will be able to understand. If you can remember anything about
how you did it, I'd be interested.


On Sun, 28 Nov 2010 15:59:08 -0800
Jason Barnett <jason.barnett71 at gmail.com> dijo:

>FYI, it is possible to force X to read the edid from a file instead of
>the monitor.  Had to do this for a couple of years with my Viewsonic
>monitor, finally I modified my monitor's firmware to match what the
>driver was wanting (different checksum) and have not had any problems
>sense.
>
>If you want details, let me know and I'll dig through my notes as I
>have forgotten the syntax for doing this..
>Jason
>
>On Sun, Nov 28, 2010 at 3:00 PM, John Jason Jordan
><johnxj at comcast.net>wrote:
>
>> On Sun, 28 Nov 2010 13:55:32 -0800
>> Bill Barry <bill at billbarry.org> dijo:
>>
>> >On Sun, Nov 28, 2010 at 12:57 PM, John Jason Jordan
>> ><johnxj at comcast.net>wrote:
>> >
>> >> I want as much screen real estate as possible for my presentation.
>> >> The projector will project 1400x1050 and can accept from my
>> >> computer up to 1600x1200. Therefore, I want my laptop to do
>> >> 1400x1050 or higher, in a 4:3 ratio. The nVidia driver offers me
>> >> only 1680x1050, 1280x1050, or 1280x960, and lower resolutions.
>> >> Thus, with the nVidia driver I can project 1680x1050, which will
>> >> be distorted to the audience, or I can project 1280x960, which
>> >> will not be distorted to the audience, but gives me less screen
>> >> real estate than the projector is capable of.
>> >>
>> >> The nouveau driver gives me options of 1680x1050 or 1400x1050, and
>> >> lesser resolutions. By setting my laptop to 1400x1050 I can
>> >> project an undistorted 1400x1050 to the audience. My laptop will
>> >> be slightly distorted, but I am looking at it right now and it is
>> >> tolerable. After the presentation I can set my laptop back to
>> >> 1680x1050.
>>
>> >So there is a problem getting the nVidia driver into the resolution
>> >you want and a problem getting the nouveau driver to display on two
>> >monitors. Why not reverse the problem. Go back to the nVidia driver
>> >at 1280x960 and get dual monitors working. Then try to find out why
>> >the nVidia driver is not offering you the resolution you want. It
>> >seems the resolution problem would be easier to solve.
>>
>> That is what I tried to do from the beginning. By reading Xorg.0.log
>> I finally determined that the nVidia driver was misinterpreting the
>> EDID data from the laptop screen. In other words, fixing the
>> resolution problem in the nVidia driver required a bugfix from
>> nVidia. Meantime, I knew that the nouveau driver would give me the
>> resolution I wanted because the Lucid live CD uses the nouveau
>> driver and it offered me 1400x1050. I also knew that it was possible
>> to get the nouveau driver to connect to the projector because others
>> have done so. And from reading the troubleshooting page on nouveau's
>> site I'm pretty sure I can fix what is wrong. I've just had other
>> things to do so far today. But before the day is out I'll probably
>> have the external monitor working. (Crossing fingers.)
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