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Old 11-22-07, 11:49 AM   #8
mc42
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Join Date: May 2006
Posts: 4
Lightbulb Re: Request for new Sticky about resolution issue!

After some googling I discovered that all our GeForce FX (5200)
have a broken TMDS encoder that works below the DVI specification.
(see: http://en.wikipedia.org/wiki/Digital_Visual_Interface
"The DVI specification mandates a fixed single link maximum pixel clock frequency of 165 MHz")

The lower maximal frequency is detected by the driver and the right timing for monitor is blocked, i.e.:
Code:
#(--) NVIDIA(0): Detailed Timings:
#(--) NVIDIA(0):   1680 x 1050 @ 60 Hz
#(--) NVIDIA(0):     Pixel Clock      : 146.25 MHz
#(--) NVIDIA(0):     HRes, HSyncStart : 1680, 1784
#(--) NVIDIA(0):     HSyncEnd, HTotal : 1960, 2240
#(--) NVIDIA(0):     VRes, VSyncStart : 1050, 1053
#(--) NVIDIA(0):     VSyncEnd, VTotal : 1059, 1089
#(--) NVIDIA(0):     H/V Polarity     : -/+
The best solution for this I found, is to use (119MHz) reduced blanking modeline.

In the Section "Monitor":
Option "ExactModeTimingsDVI" "true"
Modeline "1680x1050rb" 119.00 1680 1728 1760 1840 1050 1053 1059 1080 -hsync +vsync

Section "Device":
Option "ModeValidation" "NoDFPNativeResolutionCheck"

and in the SubSection "Display" write:
Modes "1680x1050rb"

If that for some reason doesn't work, you can try the

Option "ModeValidation" "NoMaxPClkCheck"

but as zander wrote, this may kill the TMDS encoder on the card a bit sooner than the new 3D AMD open source drivers arrives

Last edited by mc42; 11-22-07 at 03:19 PM. Reason: typo
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