ATI Drivers report bogus dot_clock to xvidtune

Greg Stark gsstark at
Tue Mar 28 09:31:00 PST 2006

When I ran xvidtune It reports the dot clock is 1976225.70Mhz. Of course
that's wrong, my graphics card is not capable of driving a 1.9 petahertz

I suspect this is the root cause of the problems I have and another user has
reported with using mythtv with an ATI card. Since mythtv attempts to sync to
the vertical refresh it gets *very* confused trying to match this refresh

I'm not sure if this is a display bug in xvidtune or a bug in the driver so I
wrote a little test program to print the output from XF86VidModeGetModeLine:

dot_clock: 1976225695
 hdisplay: 3520
 hsyncstart: 3568
 hsyncend: 3600
 htotal: 3680
 vdisplay: 1200
 vsyncstart: 1203
 vsyncend: 1209
 vtotal: 1235
 flags: 80000000
 privsize: 0
rate: 434832.268747

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