[mythtv-users] Tearing and the mythical VBlank ioctl

[William Uther]

Hi,
   My myth box has been tearing during playback.  It was pointed out 
that starting mythfrontend with the "-v playback" option would give me 
debugging information: and I found out that I didn't have DRI drivers 
for my savage chipset.  I installed the latest savage drivers, version 
of Xorg, etc.  Then I got this error:

 > DRMVideoSync: VBlank ioctl did not work, unimplemented in this driver?

I posted on the savage driver mailing list and it was confirmed that 
this was unimplemented as yet.

So....  I then went out and bought myself a cheap nVidia card.  I 
figured that hardware shouldn't be an issue here - getting the vblank 
information is a fairly basic function.  So I bought myself the 
cheapest nVidia I could find - a Gigabyte board with an nVidia MX 4000 
chipset.

I managed to get the nVidia drivers installed (2.6.10 kernel requires a 
patched nVidia driver, sigh).  I then started up myth with the -v 
playback option and got:

 > nVidiaVideoSync: VBlank ioctl did not work, unimplemented in this 
driver?

WTF?!?  The nVidiaVideoSync method was written to work with those 
nVidia drivers, wasn't it?

Does anyone actually implement this ioctl?  Has anyone managed to get 
either DRMVideoSync or nVidiaVideoSync to work?  If so, what chipset 
and driver combination did you use?

Frustrated,

Will          :-}

--
Dr William Uther                            National ICT Australia
Phone: +61 2 9385 6357             School of Computer Science and 
Engineering
Email: willu at cse.unsw.edu.au             University of New South Wales
Web: http://www.cse.unsw.edu.au/~willu/        Sydney, Australia