[WHY]

For additional power savings, PSR SU (also referred to as PSR2) can be
enabled on eDP panels with PSR SU support.

PSR2 saves more power compared to PSR1 by allowing more opportunities
for the display hardware to be shut down. In comparison to PSR1, Shut
down can now occur in-between frames, as well as in display regions
where there is no visible update. In otherwords, it allows for some
display hw components to be enabled only for a **selectively updated**
region of the visible display. Hence PSR SU.

[HOW]

To define the SU region, support from the OS is required. OS needs to
inform driver of damaged regions that need to be flushed to the eDP
panel. Today, such support is lacking in most compositors.

Therefore, an in-between solution is to implement PSR SU for MPO and
cursor scenarios. The plane bounds can be used to define the damaged
region to be flushed to panel. This is achieved by:

* Leveraging dm_crtc_state->mpo_requested flag to identify when MPO is
  enabled.
* If MPO is enabled, only add updated plane bounds to dirty region.
  Determine plane update by either:
    * Existence of drm damaged clips attached to the plane (added by a
      damage-aware compositor)
    * Change in fb id (flip)
    * Change in plane bounds (position and dimensions)
* If cursor is enabled, the old_pos and new_pos of cursor plus cursor
  size is used as damaged regions(*).

(*) Cursor updates follow a different code path through DC. PSR SU for
cursor is already implemented in DC, and the only thing required to
enable is to set DC_PSR_VERSION_SU_1 on the eDP link. See
dcn10_dmub_update_cursor_data().
Signed-off-by: NLeo Li <sunpeng.li@amd.com>
Acked-by: NLeo Li <sunpeng.li@amd.com>
Reviewed-by: NHarry Wentland <harry.wentland@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>