The symptom is that mythtv can't play video smoothly, instead it plays for a few frames then stops for about a second. Then resumes and then stops... The cause I believe is that it's trying to sync to a bogus refresh rate it's calculating based on bogus data returned by XF86VidModeGetModeLine. Also, in XVidTune it says "Pixel Clock (Mhz): 1976225.70" which of course is ridiculous. If my graphics card could handle a 1.9 petahertz signal it would be doing something more exciting than driving my monitors. I wrote a small C program to test the output of XF86VidModeGetModeLine and this is the result it output: 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 And mythtv has trouble keeping up with a 434khz frame rate...
Created attachment 5105 [details] Test program
it looks like the modeline struct is just never getting filled in properly. can you attach your config file and log so I can figure out what path this is hitting?
I think this is caused by MergedFB, see corresponding thread on the xorg list.
This should be fixed by e742aeb28c7d9d6e75932c408bcc7c44af52e303 I assume. If not reopen.
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