Solved
In fact there IS A BUG during stm32l496 + TouchGFX(4.15, Freertos & No dma mode)
Just like this link
https://community.st.com/s/question/0D53W00000AYdlzSAD/basic-touchgfx-application-dont-work
when anyone start a basic touchGFX project with stm32l496 , using Freertos & no dma mode, u will get TouchGFXHAL::flushFrameBuffer never called because of endless waiting for dma unlock.
if u set lockDMAToFrontPorch(false); than it works but you will lost right refresh freq because the engin will create one frame after another and never pause, even u just called touchgfx::OSWrappers::signalVSync() one time.
and no one give an anwser by far. good job.
