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iMX6 HW decimator not working when capturing interlaced video over mipi

Question asked by edison.fernandez on Aug 3, 2017
Latest reply on Aug 22, 2017 by Anuradha Ranasinghe

Hi,

 

I've been working on adding support to capture 1080i60 video from the MIPI interface on an iMX6 board. For this I'm using the Toshiba TC358743 and I'm able to properly capture and deinterlace the video, this by setting params.csi_mem.interlaced properly in true so the IMDAC channel gets properly configured for interlaced video.

I need to be able to reduce the framerate and for this purpose I'm using the hardware decimator so I just drop frames right from the capture. I'm doing so by  using the IPUx_CSI0_SKIP register. I can conform it works as expected when I'm capturing any progressive resolution, however, when capturing 1080i, the IDMA channel doesn't get any data so I end up with dqueue timeout error. I also tested the decimator capturing 1080i60 but with a GS2971 which uses the parallel interface and it works with no problem so my guess is that the issue could be related to the mipi interface when capturing interlaced video. 

The weird part is that I checked the error registers and they don't report any error.

 

Has anyone seen such behaviour before? To me it looks like all the frames are being dropped.

 

Any help would be really appreciated.

 

Regards,

Edison

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