On Thu, Jun 22, 2017 at 04:11:03PM +0000, Tsai, Nicholas wrote: > Thanks for your quickly reply. > Because I am not familiar about the Linux upstream, could you point > out where could I read the" Documentation/development_process/"? That is a directory path within the kernel source tree itself. Or you can read it online on many sites that build the kernel documentation tree. One example would be the following link: https://01.org/linuxgraphics/gfx-docs/drm/process/development-process.html hope this helps, greg k-h