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Black flashes in video on high-resolution display (IPU)

Question asked by Wouter Vanhauwaert on Jul 4, 2018
Latest reply on Jul 15, 2018 by Joan Xie

We are having some issues playing full-resolution video's on our imx53 1920x1080 platform.

It gives some IPU int errors,resulting in black video's once in a while (no signal). As we are streaming our video without closing down the receiver, eventually, it ends up in complete black-out of the screen.

We're on 2.6.35-maintain kernel.

Applying a patch based on 

ENGR00133034 ipuv3: fix black flash issue during high resolution video playback

Basically only:

/*
* non-interleaving format need enlarge burst size
* to work-around black flash issue.
*/
if (((dma_chan == 23) || (dma_chan == 27) || (dma_chan == 28))
&& ((pixel_fmt == IPU_PIX_FMT_YUV420P) ||
(pixel_fmt == IPU_PIX_FMT_YUV420P2) ||
(pixel_fmt == IPU_PIX_FMT_YVU422P) ||
(pixel_fmt == IPU_PIX_FMT_YUV422P) ||
(pixel_fmt == IPU_PIX_FMT_NV12))) {
_ipu_ch_param_set_burst_size(dma_chan, 64);
} else {
_ipu_ch_param_set_burst_size(dma_chan, 32);
}

gives a huge relieve for video playing. No black screens afterwards. But we seem to face an issue with the normal video framebuffer...

It's like every odd column of 16 pixels width is overwriting column next to it. Video itself is fine. Would anyone know what to change next to above change? burst_size is changed to 32, but what to change to avoid above problem?

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