The framebuffer update sends the contents of the framebuffer to the eink screen. It is used by programs the write directly to the framebuffer. You can do it with
eips '' (two single quotes), or you can do it with
cat 1 > /proc/eink_fb/update_display, or you can do it with an ioctl() call from a C program.
The eips command works on any eink kindle. The proc port is only for the K3 and earlier (but K4 supports it if booted from main). The K5 does not have the /proc port and uses a different ioctl() call, so the eips command is popular there.
lipc events tell the framework to redraw its screens.
Screen rotation can also be done with /proc ports, but that really confuses the framework, so it is better to ask the framework to do it with lipc commands.
