Rather than signaling a full update of the display from userspace via a
console switch, this patch introduces 2 files int /sys/power,
wait_for_fb_sleep and wait_for_fb_wake. Reading these files will block
until the requested state has been entered. When a read from
wait_for_fb_sleep returns userspace should stop drawing. When
wait_for_fb_wake returns, it should do a full update. If either are called
when the fb driver is already in the requested state, they will return
immediately.
Signed-off-by: Rebecca Schultz <rschultz@google.com>
Signed-off-by: Arve Hjønnevåg <arve@android.com>
cc2ae286f8