Some stange screentearing in a stm32f769 discovery

[OscarMonedero]

LVGL version

v9.1.1

What happened?

Hi,

I've detect this strange bug like a screen tearing, it happens when i try to avoid the screen tearing by using the TFT_NO_TEARING with ZONES = 4.

Any idea for how i can solve this? Thanks

https://github.com/lvgl/lvgl/assets/80752001/3149770c-d349-47ec-b90b-5531a0e87057

https://github.com/lvgl/lvgl/assets/80752001/1009d05a-4cd0-453f-959c-c0b4033000cc

How to reproduce?

No response

[OscarMonedero]

Also if i enable the color depth with RGB888 the aplication doesn't work correctly, but in my .ioc file i've got the ltdc set to rgb888 24 bits dsi mode is there something i'm missing?

[kisvegabor]

I've updated LVGL in the lv_port_stm32f769 repo but I can't see the tearing. Have you modified anything else in the project (except enabling TFT_NO_TEARING)?

[OscarMonedero]

i didn't, it could be a hardware problem? or maybe a bad configuration with the ide?

[OscarMonedero]

im trying to enable 8 zones for sthe screen to try to minimize the problem, but i don't know which value should have scanline in this case:

if ZONES == 2

uint16_t scanline = 200;

elif ZONES == 4

uint16_t scanline = 283;

elif ZONES == 8

uint16_t scanline = 360;

[OscarMonedero]

Also in the port project i have the same issue but the area of ​​the screen that causes problems is smaller

[kisvegabor]

I don't think it's a hardware issue, but don't have any ideas either :slightly_frowning_face:

Just an absurd one: Eclipse already tricked me a few times and haven't compiled the projects automatically when I changed something. So are you sure that the project is rebuilt with the changed TFT_NO_TEARING setting?

[OscarMonedero]

Yes, when i don´t use it, all the screen has a tearing issue

im trying to enable 8 zones for sthe screen to try to minimize the problem, but i don't know which value should have scanline in this case: #if ZONES == 2 uint16_t scanline = 200; #elif ZONES == 4 uint16_t scanline = 283; #elif ZONES == 8 uint16_t scanline = 360;

I'm trying this to minimize the problem, but i don't know how to obtain the scanline value for 8 ZONES

[kisvegabor]

I've created the driver based on an ST example, and just used the values from there. You also have a 800x480 display, right?

[OscarMonedero]

yes, i have the screen that comes with the kit

[kisvegabor]

Phew, I'm sorry but I have no idea :cry:

[lvgl-bot]

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[OscarMonedero]

don't worry, thanks!! I'm also trying now to use LVGL in a stm32u5g9j-dk1. Is there any port for it or plan to port it? If hte answer is no, could you help me on what i need to use LVGL on it?

[kisvegabor]

We have just published this project for a Riverdi STM32U5 board. I hope it helps.