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Old 04-23-06, 07:34 PM   #1
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Join Date: Apr 2006
Posts: 6
Unhappy 1.0-8756 fails to detect internal dual-link TMDS on 7900GT

I am trying to get an IBM T221 monitor working with a 7900GT card.
This monitor worked fine at 1920x1200@41Hz with an ATI Radeon 8500 in a
different system.

But it does not work very well with the linux nvidia driver 1.0-8756.
I took the xorg.conf used for the Radeon and made the minimal changes required
to convert it over to using the nvidia card. In particular I did not change
the modeline.

Also, there is one problem with the T221 monitor - it does not report an EDID
that the Xorg server can understand. So, I have had to use the following

Option "UseEDID" "false"
Option "ExactModeTimingsDVI" "true"
Option "ConnectedMonitor" "dfp"


I have found that if I start up the Xorg server with another DVI monitor
connected to the 7900GT and then switch it over to the T221, the display is
fine. BUT, if I start the X server with the T221 connected, it fails.

I have run X -logverbose 6 for both the "good" (works when connected to another
DVI monitor first) and the "bad" (connected to the T221 to start). I will
attach the logs, but I can summarize the difference here - it is only two line:


(--) NVIDIA(0): DFP-0: Internal Dual Link TMDS
(--) NVIDIA(0): DFP-0: Native FlatPanel Scaling is supported


(--) NVIDIA(0): DFP-0: Internal Single Link TMDS
(--) NVIDIA(0): DFP-0: Native FlatPanel Scaling is not supported

For what it is worth - the "bad" output is identical to the log output when
there is no cable connected to the card's DVI port at all.

I could not find an option listed in the NVIDIA Readme that would allow me to
force the driver to detect the Dual-Link TMDS.

Obviously, booting with one monitor and switching to the T221 is not feasible,
so I really, really need the driver to work and will be happy to test a beta

Xorg.0.log-verbose-good - log of a good boot connected to another monitor 1st
Xorg.0.log-verbose-bad - log of a failed boot connected to the T221
xorg.conf - conf file, minimal changes from a working Radeon vers

Thank you
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