dvi cabling again! - X

This is a discussion on dvi cabling again! - X ; I got a LG L1930B lcd monitor a couple of days ago & it works very well with an analog cable. Switched to a DVI-D cable & linux has a problem. The system has a Matrox G550 & running SuSE ...

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  1. dvi cabling again!

    I got a LG L1930B lcd monitor a couple of days ago & it works very well
    with an analog cable. Switched to a DVI-D cable & linux has a problem.

    The system has a Matrox G550 & running SuSE 9.2 with their 2.6.8-24.5
    kernel.

    Getting to X works but crashes when getting out; also don't think the
    problem is with X (xorg 6.8.1) as the initial splash screen also goes
    crazy which may imply a problem with graphics in general?

    Is it also an ncurses problem?

    At first I thought it was a problem with doing 24 bit X but problems
    remain using 16 bit X config.

    All is well when using the old reliable analog vga cable. So is the
    kernel not doing something well with digital signals?

    WinXP has not encountered any problem with the switch to the DVI-D
    cable, only linux or just SuSE 9.2.

    Have read about DVI cabling problems in the newsgroup but no solution
    appears to have been found &/or *acknowledged*.


  2. Re: dvi cabling again!

    On Thu, 16 Dec 2004 16:05:35 -0600, lew@csus_abcdefg.edu staggered into
    the Black Sun and said:
    > I got a LG L1930B lcd monitor a couple of days ago & it works very
    > well with an analog cable. Switched to a DVI-D cable & linux has a
    > problem. The system has a Matrox G550 & running SuSE 9.2 with their
    > 2.6.8-24.5 kernel.


    Matrox, so you're probably using the mga X server. Did you read the man
    page for mga? I'll quote an excerpt:

    Support for the second head on G400 cards requires a binary-only
    "mga_hal" module that is available from Matrox ,
    and may be on the CD supplied with the card. That module also provides
    various other enhancements, and may be necessary to use the DVI
    (digital) output on the G550 (and other cards).

    > Getting to X works but crashes when getting out; also don't think the
    > problem is with X (xorg 6.8.1) as the initial splash screen also goes
    > crazy which may imply a problem with graphics in general?


    Yep. First thing to do is to try the evil binary-only mga_hal X server
    and see if it works better. Read the README that comes with that X
    server and follow its advice.

    > Is it also an ncurses problem?


    No. ncurses is a library that provides useful capabilities to
    console-based applications. It has nothing to do with X, although you
    can run ncurses applications in an xterm/konsole.

    > All is well when using the old reliable analog vga cable. So is the
    > kernel not doing something well with digital signals?


    This isn't a kernel problem; it's an X problem.

    > Have read about DVI cabling problems in the newsgroup but no solution
    > appears to have been found &/or *acknowledged*.


    If mga_hal works for you, say so in a followup to this message so that
    http://groups.google.com/advanced_group_search will preserve it for
    others who may have the same question. HTH,

    --
    Matt G|There is no Darkness in Eternity/But only Light too dim for us to see
    Brainbench MVP for Linux Admin / mail: TRAP + SPAN don't belong
    http://www.brainbench.com / Hire me!
    -----------------------------/ http://crow202.dyndns.org/~mhgraham/resume

  3. Re: dvi cabling again!

    begin Dances With Crows wrote:

    > On Thu, 16 Dec 2004 16:05:35 -0600, lew@csus_abcdefg.edu staggered into
    > the Black Sun and said:
    >> I got a LG L1930B lcd monitor a couple of days ago & it works very
    >> well with an analog cable. Switched to a DVI-D cable & linux has a
    >> problem. The system has a Matrox G550 & running SuSE 9.2 with their
    >> 2.6.8-24.5 kernel.

    >
    > Matrox, so you're probably using the mga X server. Did you read the man
    > page for mga? I'll quote an excerpt:
    >
    > Support for the second head on G400 cards requires a binary-only
    > "mga_hal" module that is available from Matrox ,
    > and may be on the CD supplied with the card. That module also provides
    > various other enhancements, and may be necessary to use the DVI
    > (digital) output on the G550 (and other cards).
    >


    mga_hal is supplied with SuSE, on DVD and CD

    I have a dual-monitor setup working, right out of the box. I did *not* go to
    the Matrox site to get any drivers, since it seems SuSE supplies working
    ones

    < snip >

    --
    Microsoft's Guide To System Design:
    Let it get in YOUR way. The problem for your problem.


  4. Re: dvi cabling again!

    On 2004-12-16, Dances With Crows wrote:
    > On Thu, 16 Dec 2004 16:05:35 -0600, lew@csus_abcdefg.edu staggered into
    > the Black Sun and said:
    >> I got a LG L1930B lcd monitor a couple of days ago & it works very
    >> well with an analog cable. Switched to a DVI-D cable & linux has a
    >> problem. The system has a Matrox G550 & running SuSE 9.2 with their
    >> 2.6.8-24.5 kernel.

    >
    > Matrox, so you're probably using the mga X server. Did you read the man
    > page for mga? I'll quote an excerpt:
    >
    > Support for the second head on G400 cards requires a binary-only
    > "mga_hal" module that is available from Matrox ,
    > and may be on the CD supplied with the card. That module also provides
    > various other enhancements, and may be necessary to use the DVI
    > (digital) output on the G550 (and other cards).


    ummmm, I'm not doing Dual-head, just the lcd monitor. Also the 4.1
    drivers don't work either.

    >
    >> Getting to X works but crashes when getting out; also don't think the
    >> problem is with X (xorg 6.8.1) as the initial splash screen also goes
    >> crazy which may imply a problem with graphics in general?

    >
    > Yep. First thing to do is to try the evil binary-only mga_hal X server
    > and see if it works better. Read the README that comes with that X
    > server and follow its advice.
    >


    I am using the binary-only mga from the install; even tried the 4.1
    binary-only from matrox which didn't work either.

    The readme file for 4.1 says to use "option 'digitalscreen1' 'yes'"
    for possibly dual-head but was not clear; will try tho.

    >> Is it also an ncurses problem?

    >
    > No. ncurses is a library that provides useful capabilities to
    > console-based applications. It has nothing to do with X, although you
    > can run ncurses applications in an xterm/konsole.
    >


    Still doesn't explain why the messed-up splash screen where one only
    see some "blocks" of color & nothing else.

    >> All is well when using the old reliable analog vga cable. So is the
    >> kernel not doing something well with digital signals?

    >
    > This isn't a kernel problem; it's an X problem.
    >
    >> Have read about DVI cabling problems in the newsgroup but no solution
    >> appears to have been found &/or *acknowledged*.

    >
    > If mga_hal works for you, say so in a followup to this message so that
    > http://groups.google.com/advanced_group_search will preserve it for
    > others who may have the same question. HTH,
    >


    I now remember that yast showed 2 monitors with 1 as "unknown" which may
    be the reason things went wrong; will see what happens when I remove
    the 2nd unknown monitor. It is probably the linux version of mga
    installs for dual-head without letting the user choose not to do dual-head
    like in windowd.


  5. Re: dvi cabling again!

    lew@csus_abcdefg.edu wrote:
    > I got a LG L1930B lcd monitor a couple of days ago & it works very well
    > with an analog cable. Switched to a DVI-D cable & linux has a problem.
    >
    > The system has a Matrox G550 & running SuSE 9.2 with their 2.6.8-24.5
    > kernel.
    >
    > Getting to X works but crashes when getting out; also don't think the
    > problem is with X (xorg 6.8.1) as the initial splash screen also goes
    > crazy which may imply a problem with graphics in general?
    >

    This is a known problem of the G550, afaik unresolved.
    Go to matrox forum for more info
    http://www.matrox.com/mga/support/forum/agree.cfm
    then enter linux forum

  6. Re: dvi cabling again!

    In article <32md4vF3nmu9iU1@individual.net>, Ed Koan wrote:
    > lew@csus_abcdefg.edu wrote:
    >> I got a LG L1930B lcd monitor a couple of days ago & it works very well
    >> with an analog cable. Switched to a DVI-D cable & linux has a problem.
    >>
    >> The system has a Matrox G550 & running SuSE 9.2 with their 2.6.8-24.5
    >> kernel.
    >>
    >> Getting to X works but crashes when getting out; also don't think the
    >> problem is with X (xorg 6.8.1) as the initial splash screen also goes
    >> crazy which may imply a problem with graphics in general?
    >>

    > This is a known problem of the G550, afaik unresolved.
    > Go to matrox forum for more info
    > http://www.matrox.com/mga/support/forum/agree.cfm
    > then enter linux forum


    Thanks, I will check the forum more carefully.

    I "just" finished checking the logs for X in /var/log & there was
    a Xorg.0.0.log (a log of a good X, probably using the vga cable)
    & a Xorg.0.0.log where it was the "latest" X attempt.

    It looked like the driver loaded ok & HAL also got loaded. A couple
    of things were different as the Xorg.0.0.log said that "RAC" was
    loaded while the bad X didn't load the "RAC" (whatever that is).

    The biggie was that the "bad" X had the last line saying:
    "SetClientVersion 0 8" which is when the blank display occured.
    The "good" X log didn't have any line referring to SetClientVersion!

    I am more confused now as it does look like the Matrox driver loaded
    ok as well as the HAL got installed ok........

    Will now try to track *SetClientVersion" for X & why it shows up
    & by whom.

    Should have looked at the expanded log but sometimes the grub init
    graphics display for OS selection shows up clearly & other times it
    is garbage which also confused me as it would indicate a possible
    video card problem.


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