Add AVR step support so SW can trigger a late frame and instead
of immediately triggering, HW will perform the update at the
start of the next step interval. This allows for a fixed SW
vsync timeline to be maintained in userland, eliminating the
usual drift from the actual HW vsync caused by a late frame.
This change adds AVR_STEP support via a DRM property.
Change-Id: I4cf8a296989805f134c2165a3bed0b050bb09c96
Signed-off-by: Steve Cohen <cohens@codeaurora.org>
cf86c94f8e