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PxP and VSYNC; Image tearing

Question asked by Brandon Schaefer on Nov 10, 2016
Latest reply on Jan 2, 2018 by Brandon Schaefer

processor: i.MX7

kernel: 4.1.15

 

Hello,

 

I'm having issues preventing tearing to occur when displaying to an LCD panel. We are using pxp hardware via v4l2 output node to perform rotation of images and display them. I attempted to use FBIO_WAITFORVSYNC and MXCFB_WAIT_FOR_VSYNC, which didn't improve the tearing issue.

 

Does pxp hardware/driver handle syncing to LCDIF to prevent this issue? I know this issue can be solved by double buffering fb device and swapping pages, but I was hoping a similar solution could be possible using only v4l2 API and PxP.

 

EDIT: Seems like I need to configure pxp to output to a framebuffer device, though I'm still learning about PxP driver interface. Is this possible with v4l2 API or will I need to use /dev/pxp_device?

 

Let me know if my last assumption is incorrect, as I'd rather not make this more complicated than it needs to be. 

 

Thanks for the help,

 

Brandon

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