*BSD News Article 57696


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From: j@uriah.heep.sax.de (J Wunsch)
Newsgroups: comp.unix.bsd.freebsd.misc
Subject: Re: XFree312 doesn't restore text mode
Date: 23 Dec 1995 14:50:22 GMT
Organization: Private BSD site, Dresden
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References: <4bbggc$ndq@gemini.coi.pw.edu.pl> <4bc1cf$phk@gemini.coi.pw.edu.pl> <4bc4op$pud@gemini.coi.pw.edu.pl>
Reply-To: joerg_wunsch@uriah.heep.sax.de (Joerg Wunsch)
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gjb@ogg.ii.pw.edu.pl (Grzegorz J. Blinowski) writes:

> The problem seems to be related to the sc0 driver, it reports
> sc0: .. VGA MONO .. early during the boot phase,
> a quick peek into the source code, reveals that
> the VGA type detection is automatic (I may be wrong here)
> So why the VGA type is incorrectly determined ???

Since your VGA misdetects your monitor as a monochrome one.

This happens for example for some monitors that are attempting to
automatically determine whether the input signal is on the BNC or the
VGA connector.  While there is no input signal at all (e.g.  after a
hardware reset), they toggle every few seconds between both input
sources until a signal is found.  If the VGA's monitor probe happens
just in the moment where the monitor was looking at the wrong input
source, the VGA fails to ``see'' the monitor ID pins, and silently
assumes a monochrome monitor.

Another combination where i found such a misbehaviour was a monitor
with power management.  On each hardware reset, both sync signals drop
at the monitor's input, so the monitor decides to go to bed.  This
caused the monitor to turn its power supply off, and therefore also to
remove the power from the monitor ID pins.  Same as above, the VGA
detected a ``monochhrome'' monitor in 8 out of 10 attempts.

(Btw., the latter example was nothing less than a deluxe HP
Netserver!)

-- 
cheers, J"org

joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE
Never trust an operating system you don't have sources for. ;-)