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[directfb-dev] Re: Flipping troubles - videolayer, crtc2
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[directfb-dev] Re: Flipping troubles - videolayer, crtc2



Hi,
> > > 
> > > After placing DFBM_BACKVIDEO to dlc.buffermode (as what Denis 
> > > suggested), flipping works.  However the resulting video 
> was shaky 
> > > and still has tearing.  I tested this with the i810 
> gfxdriver which 
> > > I wrote so I'm not sure if this is due to the i810's 
> implementation 
> > > of FlipBuffers.
> > > 
> > > If I use your old implementation, but just add an extra 
> instruction 
> > > to flip, ie. draw to frame, copy/blit from frame to primary, then 
> > > flip primary, the resulting video was smooth and steady.
> > > 
> > > Tony
> > > 
> > > 
> > This is same behaviour as on mga. But this happens only for 
> overlay. 
> > It look for me that I'm getting pointer to wrong buffer. 
> Simply try to 
> > set backbuffer into main memory. Than on mga overlay is not 
> updated at 
> > all. JS
> 
> Setting backbuffer to main memory disregards the FlipBuffer() 
> command, but instead calls dfb_back_to_front_copy(), which is 
> essentially a blit command.  Is the blit for YUV planars 
> fixed in 0.9.11?  Maybe this is the reason why flipping from 
> a system backbuffer does not work.
> 

After upgrading to latest CVS with YV12 BitBlt support the "new"
implementation with backbuffer in system memory works OK.

So let me summarize (all is for videolayer):
1) front buffer & back buffer in video memory, frame written directly to
back buffer by sw -> has big troubles, looks like wrong buffer is
obtained or displayed
2) front buffer in video memory & back buffer in system memory, frame
written directly by sw to back buffer -> works OK
3) front buffer & back buffer in video memory, frame written into
temporary surface (in system memory) than blit to back buffer -> works
OK

The code is same for all cases. Difference between case 1 and 2 is only
change in buffer mode during layer config.

Any suggestion how to do more investigation? So far it looks for me like
that there is sm strange around FLIP inside dfb.


						JS






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