X problem with 386ix 2.0.2 and mono VGA screen

[George A. Durden]

In article <232 at inpnms.UUCP> logan at inpnms.UUCP (Jim Logan) writes:
}In article <1990Feb19.195600.7778 at hcr.uucp> jeff at hcr.uucp (Jeffrey Roberts) writes:
}# I recently encountered an interesting problem while installing
}# 'X' windows version 1.1.1 under 386ix 2.0.2.  The installation went
}# smoothly and a new kernel was built and installed with no difficulty.
}# When 'X' is started up from any virtual terminal, ie: console, vt01 etc..
}# 'X' starts up with no problem.  If I switch to another virtual terminal
}# I can see the cursor but nothing else, ie: any characters that I type
}# are invisible.  I can switch back to the 'X' window and everything
}# looks fine.  When I leave 'X' my initial virtual terminal goes into this
}# state as well which is a problem because the only way to fix the problem
}# is to reboot the machine.  This is difficult when you cannot see what
}# you are typing.
}# 
}# This only happens when a mono VGA monitor is used.
}
}Not true.  This also happens to me when I use X with an EGA
}board.  I intend to look through the documentation to see if
}there is an ioctl() call that can be used to re-initialize the
}screen(s).  I'll let you in on it if I find anything.
}

Boy am I familiar with these bugs. First, let me comment on the X/mono
bug. I just spent a few weeks tracking this down. We, Dell, produce a
UNIX product based on ISC 2.0.2. I assumed the bug was in the Xvga
server management of the VGA controller state in vt switching. I was
wrong. The bug is in the UNIX console driver. I have fixed it in our
UNIX product Dell UNIX 1.1 update 1.1.2 and will be feeding it back
to ISC so they can provide it to their customers. I believe that a
similar problem could cause the EGA bug. The deal is for you folks
with source, the register values in the table used for reloading
the fonts for a monochrome VGA are incorrect. Sorry can't be more
specific due to Licensing Agreements (ya know the deal). You can
cause the same failure without X by starting a vpix session on
a vt and running some graphics app (ex. flight sim) and then doing
a vt flip to a UNIX vt. Notice the cursor is positioned properly,
just no characters on screen (due to lack of fonts for controller
to utilize).

 A workaround is to do:
	stty ENH_C80x25		# Change mode to anything else
 then do:
	stty VGA_MONO80x25	# Changing back causes font reload

 voila - everythings okay (at least until you vt flip into X and out
         again...)

 or

 on one of the blank VTs, start vpix and quit. Voila - fixed again.


 Hope this helps...
 Contact me via email for more discussion of this or other topics.

 George
-- 
	George A. Durden	
	Dell Computer Corporation	P#: (512) 338-8621
	9505 Arboretum Blvd.		!s: cs.utexas.edu!dell!durden
	Austin, Texas 78759		@s: durden at dell.dell.com