drm/i915/gen9: only add the planes actually affected by ddb changes

We were previously adding all the planes owned by the CRTC even when
the ddb partitioning didn't change for them. As a consequence, a lot
of functions were being called when we were just moving the cursor
around the screen, such as skylake_update_primary_plane().

This was causing flickering on the primary plane when moving the
cursor. I'm not 100% sure which operation caused the flickering, but
we were writing to a lot of registers, so it could be any of these
writes. With this patch, just moving the mouse won't add the primary
plane to the commit since it won't trigger a change in DDB
partitioning.

v2: Use skl_ddb_entry_equal() (Lyude).
v3: Change Reported-and-bisected-by: to Reported-by: for checkpatch

Fixes: 05a76d3d6ad1 ("drm/i915/skl: Ensure pipes with changed wms get added to the state")
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=97888
Cc: Mike Lothian <mike@fireburn.co.uk>
Cc: stable@vger.kernel.org
Reported-by: Mike Lothian <mike@fireburn.co.uk>
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Lyude <cpaul@redhat.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1475177808-29955-1-git-send-email-paulo.r.zanoni@intel.com
(cherry picked from commit 7f60e200e254cd53ad1bd74a56bdd23e813ac4b7)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

1 files changed, 36 insertions, 1 deletions

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index f3d370a764a3..a2f751cd187a 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -3962,6 +3962,41 @@ pipes_modified(struct drm_atomic_state *state)
         return ret;
 }
 
+int
+skl_ddb_add_affected_planes(struct intel_crtc_state *cstate)
+{
+        struct drm_atomic_state *state = cstate->base.state;
+        struct drm_device *dev = state->dev;
+        struct drm_crtc *crtc = cstate->base.crtc;
+        struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
+        struct drm_i915_private *dev_priv = to_i915(dev);
+        struct intel_atomic_state *intel_state = to_intel_atomic_state(state);
+        struct skl_ddb_allocation *new_ddb = &intel_state->wm_results.ddb;
+        struct skl_ddb_allocation *cur_ddb = &dev_priv->wm.skl_hw.ddb;
+        struct drm_plane_state *plane_state;
+        struct drm_plane *plane;
+        enum pipe pipe = intel_crtc->pipe;
+        int id;
+
+        WARN_ON(!drm_atomic_get_existing_crtc_state(state, crtc));
+
+        drm_for_each_plane_mask(plane, dev, crtc->state->plane_mask) {
+                id = skl_wm_plane_id(to_intel_plane(plane));
+
+                if (skl_ddb_entry_equal(&cur_ddb->plane[pipe][id],
+                                        &new_ddb->plane[pipe][id]) &&
+                    skl_ddb_entry_equal(&cur_ddb->y_plane[pipe][id],
+                                        &new_ddb->y_plane[pipe][id]))
+                        continue;
+
+                plane_state = drm_atomic_get_plane_state(state, plane);
+                if (IS_ERR(plane_state))
+                        return PTR_ERR(plane_state);
+        }
+
+        return 0;
+}
+
 static int
 skl_compute_ddb(struct drm_atomic_state *state)
 {
@@ -4026,7 +4061,7 @@ skl_compute_ddb(struct drm_atomic_state *state)
                 if (ret)
                         return ret;
 
-                ret = drm_atomic_add_affected_planes(state, &intel_crtc->base);
+                ret = skl_ddb_add_affected_planes(cstate);
                 if (ret)
                         return ret;
         }