Imx8qxp Android 10 480x272 24RGB screen issues

Hi Toradex Support Team,

Recently I have been working on porting an RGB24 480x272 parallel RGB screen to Android 10. We have verified that our changes worked using your linux multimedia evaluation image:

linux-colorbar-image-480x272.PNG

When porting the changes over to Android we are seeing pixel variance and some tearing at the righthand side of the screen:

It must have something to do with the resolution since the value can be adjusted in Android using the window manager… lowering the horizontal value to 475x272 yielded this result:

The pixel variance was gone, however a vertical bar existed on the far right of the screen. After testing lower resolutions on our linux and android image, this appears to just be duplication of the righthand side of the screen caused by the resolution being to low for the screen
here is an example of 400x270:

Anyway there was a final hack to get it all working, setting the device tree value to 482x272 (+2 higher than normal horz val), and then overriding the value with window manager in android to 478x272 (-2 lower than normal horz val) seemed to solve the issue:

Have you ever seen an issue like this before?
I understand you may not support Android, but I 'm trying to isolate whether this is kernel related.
Do you think this is an Android issue or a linux kernel issue?

Note the kernel version we are testing in linux is 5.4.91 while the android kernel version is 5.4.47 if that makes a difference.

My panel-timing parameters:

     clock-frequency = <9000000>;
    hactive = <480>;
    vactive = <272>;

    hsync-len = <41>;
    hfront-porch = <2>;
    hback-porch = <2>;

    vsync-len = <10>;
    vfront-porch = <2>;
    vback-porch = <2>;

The screens datasheet contains:
image
image

Thanks,

Matt

Hi @mfischer,

Personally, I haven’t seen this problem before and I don’t remember any customers with a problem like that.

Can you please try this with our 5.15 kernel to check if the problem still occurs? This is the kernel used in our BSP 6.

The timings seem to be correct as well, otherwise, you would probably see some color errors on your screen.

Best Regards,
Hiago.