Color artifacts appearing on LCD - colibri iMX6 linux eglfs

I use my custom carrier board with a 4,7" 480x272 LCD display, connected via parallel 18bit RGB interface.
vidargs passed to kernel:

video=mxcfb0:dev=lcd,EDT-480x272,if=RGB666 video=mxcfb1:off fbmem=16M

For graphic output testing, i use the Qt demo:

Qt5_CinematicExperience --platform eglfs 

With the module placed on the Colibri Evaluation Board V3.2, the demo is displayed on a VGA monitor without any errors.

But with the same module connected to my custom carrier board, I get color artifacts / outlines around all (animated) objects:

Even the tux on the startup-screen has some colored pixels around it:

Seems like a problem on rendering semitransparent outlines ob overlaying objects…
Ethernet, USB and RTC are missing on the custom carrier board. Do you have any idea about the reason for those rendering / blending errors?


I’ve seen similar color artefacts when the pixelclock is configured for the wrong polarity, i.e. the display output changes the data lines on the same pixelclock edge as the the display is sampling the data lines.

The pixelclock polarity can be set in a explicit timing, e.g. here.


Hi Max
Setting “.sync = FB_SYNC_CLK_LAT_FALL” for my mode specifier in mxc_lcdif.c solved the problem.

Thank you!