[meta-freescale] IPU alpha blending problems on mx6

[Andrea Picaro]

Hello,
We use an imx6 quad processor to run a Qt application on fb0, then
application runs gstreamer pipeline to play video on overlay buffer fb1.
Our system was previously based on kernel 3.0.35 and using mfw_isink it
worked perfectly up to 1080p. Now we are porting on kernel 4.1.15 with
Yocto Morty branch. Qt5.7 app on fb0 and play video through gstreamer on
fb1 using imxg2dvideosink.
We use alpha blending with separate alpha buffers to uncover only the video
rectangle on fb1.
In this configuration system is unstable with hdmi turning off and on
repeatedly giving errors:
[ 1568.833307] imx-ipuv3 2400000.ipu: warning: wait for bg sync eof timeout
[ 1572.143078] imx-ipuv3 2400000.ipu: IPU Warning - IPU_INT_STAT_5 =
0x88800000
[ 1572.143089] imx-ipuv3 2400000.ipu: IPU Warning - IPU_INT_STAT_10 =
0x00080000
after a while screen blanks definitivelly and i have to reboot.
It seems to strictly depend on local alpha blending since i can replicate
the issue also by running
 /unit_tests/autorun-ipu. If i use glabal alpha the problem do not appear
and i can run full screen application and video with 50% blending with no
problem so it doesn't seem to be a dma shortage.
Already tryed arg dmfc=3.
Could you help me?

Thank you

-- 
*Andrea Picaro*
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