multiple displays with different refresh rates

Loïc Le Loarer loic.le-loarer at
Tue Feb 7 14:07:09 PST 2012

Hi All,

I'm trying to play two videos on one X server with two screens with
different refresh rates (120Hz and 60Hz) without tearing.
Currently I'm using XvShmPutImage with the send_event argument set to
true on Xv ports with the XV_SYNC_TO_VBLANK attribute set.
The problem is that I'm receiving completion events for both screen at
the rhythm of the slowest screen, as if one on two event of the
fastest screen were dropped.

Do you have an idea of where I should look ?

I have verified that using only one screen is working correctly (even
the fastest at 120Hz) and that I have enough bandwidth because if I
ask for completion events only on the fastest screen and update the
slowest one on two, the speed is correct except that I have tearing on
the slowest screen.

I'm using and ubuntu 10.4 with a recent nvidia driver.

Do you have idea of what's wrong or if I'm doing the correct thing to
reach my goal ?

Thanks for your help.

Best regards,

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