STM32H747I-DISCO DSI Video Mode – Diagonal Tearing in Landscape Mode

[Shahima]

Hi,

I am using STM32H747I-DISCO with MB1166-A09 (NT35510) and Zephyr + LVGL with MIPI DSI Video Mode.

I am facing a diagonal/slanted tearing line when the display is configured in landscape mode.

• Portrait mode: works correctly
• Landscape mode: diagonal/slanted tearing appears during screen updates
• Hardware: STM32H747I-DISCO + MB1166-A09 / NT35510
• Software: Zephyr + LVGL PRO

I have found several related discussions about this issue, but I haven't found a clear solution for landscape DSI Video Mode.

Is this a known limitation/issue with the display/DSI configuration? Is there a recommended solution for running this display reliably in landscape Video Mode?

Any guidance from ST or anyone who has solved this would be greatly appreciated.

[MM..1]

This is normal for MADCTL switch only memory adressing. Driver require too scan switch and this isnt one reg.

[PeterVang]

Hi Shahima,

Your issue fundamentally comes from the fact that this display is natively “portrait mode”, meaning that its scanline moves left-right when you use it in landscape mode. If you transfer your framebuffer from top-to-bottom, this will result in a diagonal tearing line. The solution we use in TouchGFX is to define the screen as portrait (480x800) and then use the TouchGFX feature to rotate the complete GUI 90 degrees. I do not know if LVGL offer a similar feature. Here is a sketch to illustrate the my answer: