How to rotate qt when i use /dev/fb0 ?

[jiangjianghu]

qt works fine when i use export QT_QPA_PLATFORM=linuxfb:fb=/dev/fb0
but i want rotate qt screen, and i try to
export QT_QPA_EGLFS_ROTATION=90
export QT_QPA_ROTATION=linuxfb:rotation=90
But it doesn't seem to be working

[embetrix]

#478