Refer to follows: here u can search all Environment variable meaning https://codereview.qt.nokia.com/q/status:open+-is:wip https://codereview.qt.nokia.com/c/qt/qtbase/+/280681 click show all http://blog.iotwrt.com/tips/2017/06/04/swap-layer/ Drm = (gem + kms) https://man.archlinux.org/man/drm-kms.7.en trace drm source and change layer ~/SDK/kernel/drivers/gpu/drm/rockchip Env. variable reference https://github.com/MythTV/mythtv/blob/master/mythtv/libs/libmythui/platforms/mythdrmdevice.cpp export QT_QPA_PLATFORM="eglfs" export QT_QPA_EGLFS_KMS_ATOMIC=1 export QT_QPA_EGLFS_INTEGRATION="eglfs_kms" export QT_QPA_EGLFS_DEBUG="1" expoet QT_QPA_EGLFS_KMS_ZPOS=(select 1,2,3) export QT_QPA_EGLFS_FORCE888=1