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[vox-tech] Flat Panel and Linux
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[vox-tech] Flat Panel and Linux



I can't get my IBM T55D (digital flat panel, awesome picture under NT) to work
with linux.

Been searching around for hints (not many) found this link
http://slashdot.org/articles/00/02/19/1217254.shtml on slashdot.org, but I can't
make heads or tails of it (click on the link and then search the page for T55D).
I'd email the people involved in the thread but the email address is "anonymous
coward".

I'd really love to use this monitor.  Could someone please take a look at the
thread and see if you can decipher it?

>>>>>>>>>  thread below  <<<<<<<<<<<

LCD Monitors and Linux (digital, not analog) (Score:0)
by Anonymous Coward on Saturday February 19, @03:45PM EST (#29)

On a related note, does anyone have information on which (if any) digital flat
panel monitors work with Linux? I'm using an IBM T55D, and there's a horrendous
kludge to get it to work with XFree86 and the Matrox G200 (involves loadlin, DOS
stuff, and framebuffer driver). I'm trying to get it to work with a Guillemot
Hercules 3D Prophet DDR-DVI. The NVidia GeForce 256 X Server works fine with a
CRT monitor, but I can't get anything except junk to display on the LCD (it does
text mode just fine, though, and the VGA 16 server works in 640x480 so things
like XF86Setup will display). Horrors, I tried it on a Windows box and I think
it queries the flat screen for specs, because it worked perfectly without
needing any monitor info files. Any solutions or suggestions for working video
card/digital lcd combinations under Linux?


Re:LCD Monitors and Linux (digital, not analog) (Score:0)
by Anonymous Coward on Saturday February 19, @04:10PM EST (#34)

Adjust the output timings on your video card so that you are driving the panel
at no more than 60Hz. This is the native refresh rate of the panel itself, and
driving it any faster simply makes the internal Analog to Digitial Converter
inject that much more noise. Use the CRT, perhaps, and xvidtune to come up with
modelines that arrive at the resoltion and timing you desire (hint: 1024x768
60Hz would probably be the configuration you want),

I work at a large company that makes LCD panels, and I spend my days writing
embedded software to make them work. I've seen it all before, so in this case I
am guessing the monitor you have does not support high refresh rates, so you
have to make sure you are not taking modelines from a "real" multisync monitor
and trying to drive the LCD monitor. BTW, yes, Windows can check the monitor via
DDC2 EDID to determine the best refresh rates and resolutions, and I remember
reading that XFree86 does not really support this, and it is also entirely
possible that the monitor you have did not implement it properly. Finally,
someone said this already: Go Digital! Analog LCD is inferior on almost all
counts (except maybe price)

Re:LCD Monitors and Linux (digital, not analog) (Score:0)
by Anonymous Coward on Saturday February 19, @04:41PM EST (#38)

>Adjust the output timings on your video card so that you are driving the panel
at no more than 60Hz.

I spent all day trying to get it to work. I nabbed the monitor .inf file from
floppy and it had a 48.4,60,+,+ entry for 1024x768 16 bit (the only entry
actually). I assume that's horiz, vert, and positive hsync and vsync.

>so you have to make sure you are not taking modelines from a "real" multisync
monitor and trying to drive the LCD monitor

I tried bunches of them -- I found one that looked similar from a 14" IBM LCD
laptop screen (range was 31.5-48.5, 60) but no go.

>Finally, someone said this already: Go Digital!

DVI card and the monitor is DVI also. =)

What company do you work for, and have you had success getting any of the
digital monitors to work under Linux?

Is there some other setting that digital screens need?

Re:LCD Monitors and Linux (digital, not analog) (Score:0)
by Anonymous Coward on Saturday February 19, @10:29PM EST (#62)

Update -- managed to get it working with framebuffer console driver.

Used the vga=792 line in lilo for a 1024x768x24 bit screen, and that worked
okay. Then fbset -x for the lines in X.

Section "Monitor"
        Identifier "LCD Panel 1024x768"
        VendorName "IBM"
        ModelName "T55D"
      HorizSync 31.5-60 # guesses
      VertRefresh 30-80 # guesses
  Mode "1024x768"
        # D: 78.653 MHz, H: 59.949 kHz, V: 75.694 Hz
        DotClock 78.654
          HTimings 1024 1056 1184 1312
        VTimings 768 772 776 792
        Flags "-HSync" "-VSync"
EndMode
EndSection

Section "Screen"
        Driver "fbdev"
        Device "My Video Card"
        Monitor "LCD Panel 1024x768"
        DefaultColorDepth 32
    Subsection "Display"
                Depth 32
                  Modes "default"
                ViewPort 0 0
        EndSubsection
EndSection

Only the 32bit mode worked in X. I guess the normal driver isn't doing something
right since these same settings just display junk...

(I'm not sure it's even using the 1024x768 setting since it has "default"...)



Jay Strauss
jstrauss@bazillion.com
(h) 773.935.5326
(c) 312.617.0264



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