DVI output for GeoForce 8400 GS to ViewSonic VX2235wm LCD monitor doesn't work

Jonathan Kamens jik at kamens.brookline.ma.us
Tue Jan 12 15:27:44 UTC 2010

My old 32-bit system, on which I was running bleeding-edge Rawhide, died
when folks working in my house fried my motherboard by plugging a sheetrock
saw into my UPS (brilliant!).  I've replaced my old system with a home-built
system with an Asus P5Q SE2 motherboard and a GeoForce 8400 GS graphics
controller.  To allow things to stabilize for a while before going back to
bleeding-edge, I'm now running F12 with updates-testing rather than Rawhide.
Also, I've switched to 64-bit.


My monitor, a ViewSonic VX2235wm LCD, has both VGA and DVI inputs.  With my
old system, I was using VGA, since my graphics controller didn't have DVI
out.  The GeoForce, however, has DVI out, so I'd like to start using it.
The problem is that when I try to switch from VGA to DVI, the monitor claims
that it's getting no digital signal.  This could be due to any number of
different problems, e.g.:


.         Broken monitor

.         Broken graphics controller

.         Bad / incompatible DVI cable

.         Incompatibility between the kind of DVI signal the controller is
generating and the kind of signal the monitor accepts (I hear rumors that
this kind of thing happens, but I know very little about the various video
out formats and therefore have no insight into it or how to diagnose it)

.         Known bug / non-support for DVI output in kernel and/or X driver

.         Regression in kernel and/or X driver

.         Me doing something stupid


I'm hoping there's somebody here who can help me narrow down the
possibilities so that I know whether I should file a bug about this, replace
some hardware, just live with it, or what.


Here's some additional information that is probably relevant:


.         I've got no xorg.conf file (i.e., I'm using whatever settings the
X server determines automatically).

.         My SMOLT profile is at

.         When I connect the monitor with just DVI and reboot the system,
the BIOS and GRUB screens (well, I'm sure about the BIOS screens but less
certain about the GRUB screen) render just fine through DVI, but then the
screen goes blank.

.         When the DVI cable is not plugged in, xrandr says that it's not
plugged in.  When it is plugged in, xrandr acknowledges that it has been
plugged in.

.         I'm not certain, but I believe that when I unplug the DVI cable
after it has been plugged in, xrandr doesn't notice that it has been

.         Judging from my Xorg.0.log
(http://stuff.mit.edu./~jik/misc/Xorg.0.log.txt), the X server notices when
the DVI cable is inserted or removed.

.         When I open System > Preferences > Display with both VGA and DVI
connected, it acknowledges that there are two monitors connected.  If I then
tell it to mirror my screens, apply the changes, and either unplug the VGA
cable or use the monitor menu to switch to DVI input, the monitor goes
blank.  Ditto of I tell it that I want to extend my display to both screens.


I think that's everything I've got.  So, does anybody have any insights or






-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.fedoraproject.org/pipermail/test/attachments/20100112/16f5bd7b/attachment-0001.html 

More information about the test mailing list