[PATCH v4 6/6] drm/i915/xe3: introduce a dirty rectangle state variable

[Vinod Govindapillai]

To avoid programming garbage to dirty rectangle registers,
introduce a state variable to track the validity of the
dirty rectangle update scenarios. Program the dirty rectangle
coordinate only if this state variable is valid.

Signed-off-by: Vinod Govindapillai <vinod.govindapil...@intel.com>
---
 drivers/gpu/drm/i915/display/intel_fbc.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_fbc.c 
b/drivers/gpu/drm/i915/display/intel_fbc.c
index 033eb4a3eab0..ab8acb1cc090 100644
--- a/drivers/gpu/drm/i915/display/intel_fbc.c
+++ b/drivers/gpu/drm/i915/display/intel_fbc.c
@@ -91,6 +91,7 @@ struct intel_fbc_state {
        u16 interval;
        s8 fence_id;
        struct drm_rect dirty_rect;
+       bool dr_valid;
 };
 
 struct intel_fbc {
@@ -1227,6 +1228,9 @@ __intel_fbc_program_dirty_rect(struct intel_dsb *dsb, 
struct intel_plane *plane)
        if (fbc_state->plane != plane)
                return;
 
+       if (!fbc_state->dr_valid)
+               return;
+
        intel_de_write_dsb(display, dsb, XE3_FBC_DIRTY_RECT(fbc->id),
                           FBC_DIRTY_RECT_START_LINE(fbc_state->dirty_rect.y1) |
                           FBC_DIRTY_RECT_END_LINE(fbc_state->dirty_rect.y2));
@@ -1314,6 +1318,8 @@ intel_fbc_compute_dirty_rect(struct intel_atomic_state 
*state,
                if (!fbc || plane->pipe != crtc->pipe)
                        continue;
 
+               fbc->state.dr_valid = false;
+
                /* If plane not visible, dirty rect might have invalid 
coordinates */
                if (!new_plane_state->uapi.visible)
                        continue;
@@ -1323,6 +1329,8 @@ intel_fbc_compute_dirty_rect(struct intel_atomic_state 
*state,
                        continue;
 
                __intel_fbc_compute_dirty_rect(plane, old_plane_state, 
new_plane_state);
+
+               fbc->state.dr_valid = true;
        }
 }
 
-- 
2.43.0