touchgfx compression tearing

[관박.1]

I'm using TouchGFX version 4.24.1 with external flash memory mapping at address 0x90000000.

When using the original image, there are no issues. However, when using the compressed RGB565 function, a tearing effect appears on the LCD screen. If I disable 'SCB_EnableDCache()', the issue is resolved.

Therefore, I believe that 'TouchGFXGeneratedHal::InvalidateCache()' is not properly invalidating the decompression buffer

1. Is there a solution for this?
2. If I disable 'SCB_EnableDCache()', will it have a significant impact on display performance?"

[LouisB]

Hello @관박.1 ,

You mean a corrupt image ? Do you have a screenshot of the result you have with compression and SCB_EnableDCache ?

And also, what's the image format and the framebuffer format in the configuration ?

BR,

[관박.1]

Thank you, LouisB

I capture a portion of the screen.

image format : rgb565

framebuffer format : rgb565

[LouisB]

And what do you have in the default image configuration ? Try to put non opaque format to RGB565

[관박.1]

This is my TouchGFX default image configuration, and the RGB565 format option is not available in the Non-Opaque Image Format.

and, i'm sure this is cache issue.

because, for a moment, some parts of the tearing screen were flickering, displaying the correct colors.

[LouisB]

Hello @관박.1 ,

For now we didn't encounter this kind of issue with the cache, I'll talk we with the team to look for that.
"SCB_EnableDCache" seems to have side effects, like corrupting data in some cases, a workaround can be disable it so you can do your project.

BR,

[MTana.1 · Accepted solution]

I had the similar situation.

I found the text flicker and below is countermeasure. It's just for your reference.

TouchGFXHAL.cpp