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i.MX6 HDMI & CVBS Concurrent Output Problem

Question asked by Ryan Erb on Jun 13, 2014
Latest reply on Sep 10, 2014 by gusarambula

Hello,

 

HDMI and CVBS cannot run concurrently at the same time. As soon as you start one, the other goes blank.

 

We are testing in Yocto 1.5 with the 3.10.17 kernel.


We are using patches from Freescale for BT656 and ADV7393 here: https://community.freescale.com/docs/DOC-94019 and have ported those to the freescale 3.10.17_1.0.0_ga kernel and that we are using the yocto v1.5 BSP

We found that even if you re-order the mxcfb devices you get the same result. Note that on the board LVDS is IPU1_DISP0, HDMI is IPU1_DISP1 and ADV739x is IPU2_DISP0 so this doesn't seem to be an issue of 2 displays on one IPU.


To recreate the issue:

cat /proc/cmdline

console=ttymxc1,115200 root=ubi0:rootfs ubi.mtd=2 rootfstype=ubifs video=mxcfb1:dev=hdmi,1280x720M@60,if=RGB24 video=mxcfb2:dev=adv739x,BT656-NTSC,if=BT656,fbpix=RGB565 video=mxcfb0:dev=ldb,LDB-XGA,if=RGB666 video=mxcfb3:off debug

echo "V:1920x1080p-60" > /sys/class/graphics/fb0/mode

gst-launch videotestsrc ! mfw_v4lsink device=/dev/video16 &

gst-launch videotestsrc ! mfw_v4lsink device=/dev/video18 &

 

if you force the HDMI output to 480p this issue is not present:

echo "D:640x480p-60" > /sys/class/graphics/fb0/mode gst-launch videotestsrc ! mfw_v4lsink device=/dev/video16 & gst-launch videotestsrc ! mfw_v4lsink device=/dev/video18 &

 

 

Kevin WongArpan Chakravarty

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