Configuration of display settings and timings on IMX6

mkock · October 23, 2018, 5:44pm

Three photos taken right after each other, each with the exact same camera settings. Please note the vertical aligned toradex logo, which should not be there but is clearly visible on the screen.

The perceived flicker frequency depends on the refresh rate. I would guess the perceived flicker frequency to be 15 Hz, roughly estimated.

[upload|RBF7PC4LYfgTPuldrydZ6net6mM=]

[upload|il/Zrsw7CY8rXM4OpBmjjCdy00o=]

[upload|sJrNh2Ywk+RY+YGMWoB6jEzJ3/Y=]

one more photo without rotation:

[upload|+K0aFMS6QgY3cRdwx/Kzr7ChaM0=]

mkock · October 23, 2018, 11:09pm

this is how the system comes up after boot. Timings and resolution are completely wrong, but no flickering:

 mxc_sdc_fb fb@0: 1024x600 h_sync,r,l: 5,43,104  v_sync,l,u: 5,20,24 pixclock=45000000 Hz

I then use the following commands to set the right settings:

xrandr --newmode  "test12"    39.988260 480 644 654 743 854 864 874 897 -hsync -vsync
xrandr --addmode "DISP3 BG - DI1" test12
xrandr --output "DISP3 BG - DI1" --mode test12
xrandr -o left

see photos above for results

jaski.tx · October 25, 2018, 2:27pm

@mkock: Unfortunately the photos were not uploaded. Could you try to upload the photos again?

mkock · October 25, 2018, 2:40pm

link

fotos 54, 55, 56 belong together.

jaski.tx · October 29, 2018, 8:55am

Thanks for the file.

Is the colour output correct when you don’t do the rotation? Could you upload also picture for non rotated output?

Thanks.

mkock · October 30, 2018, 4:19pm

no obviously there are still images with wrong data in between and I guess that this is why the image is perceived as flickering.

I took one photo how the system (or X) comes up after boot: 0142.jpg. (timings see above). No flicker at all. I still was not able to configure the device tree, so that X starts with the intended timings.

All other photos were taken after applying the xrandr commands times (timings see above). ->Flicker problem

Fotos

mkock · October 30, 2018, 6:46pm

please note, that the flicker problem is time variant and occurs only sometimes. (without changing anything). Initializing (and resetting) the display via SPI does not change anything. When no flickering is visible, the ghost images is almost gone as well.

marcel.tx · October 31, 2018, 3:17pm

Is there any particular reason for you to set this question on private? With private questions there is no way for the community to provide feedback or profit from any feedback.