IMX8MP LVDS Panel works on default Zeus but not default Kirkstone/Scargath

[synthesys]

Hello,

I'm working with an im8xmp board that is running a custom display using LVDS. It will run two displays separately: 640 x 480 @ 60 HZ and 1024 x 768 @ 60 HZ. Not concurrently, separate SKUs. 

Using Scargath (kernel v6.6.5.2_2.2.0) for yocto and flashing out-of-the-box fsl-imx-qt6 image, the display shows signs of tearing and symptoms of the incorrect timings.  Even with modified timings, it doesn't show as expected. 

This is not the case when Zeus (kernel imx_5.4.70_2.3.2) is used. No signs of tearing or bad timings for either display and panel timings/image was not changed from default.

Has the drm, including imx, drivers been updated from 5.4 to 6.6 kernel to affect LVDS like this? I noticed that nxp's media mix using npu was added since 5.4, would this affect it?

How can i  get the LVDS panels working, like they are on default Zeus, with Scargath?

Thanks

[Bio_TICFSL]

Hello,

Yes both were update but your LVDS have to be working, please check the dtb according to each BSP, this should be the issue.

Regards 

[synthesys]

Hello,

Thank you for the response.

Like i mentioned previously, I've loaded the default DTB (no changes) for Zeus and Scargath. 

Zeus has slight discoloration but the picture looks fine.

Scargath has serious tearing and the picture is completely unstable. 

Both of the panel timings are exactly the same in the device tree. This leads me to believe its a driver change or something else has been added to the default device tree of Scargath, not panel timings, that causes this problem.

Please see the attached photos. 

[Bio_TICFSL]

Hi,

This is with MX6? which BSP are you using? which device on the lVDS? We are going try to reproduce it here.

Regards