[PATCH 5.15 079/172] drm/i915: Populate pipe dbuf slices more accurately during readout

[Greg Kroah-Hartman]

From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>

commit 85bb289215cf37e05e9581b39b114db1293f9ecd upstream.

During readout we cannot assume the planes are actually using the
slices they are supposed to use. The BIOS may have misprogrammed
things and put the planes onto the wrong dbuf slices. So let's
do the readout more carefully to make sure we really know which
dbuf slices are actually in use by the pipe at the time.

Cc: <stable@xxxxxxxxxxxxxxx> # v5.14+
Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20220204141818.1900-2-ville.syrjala@xxxxxxxxxxxxxxx
Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@xxxxxxxxx>
(cherry picked from commit b3dcc6dc0f32612d04839c2fb32e94d0ebf92c98)
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/gpu/drm/i915/intel_pm.c |   13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -6634,6 +6634,7 @@ void skl_wm_get_hw_state(struct drm_i915
 		enum pipe pipe = crtc->pipe;
 		unsigned int mbus_offset;
 		enum plane_id plane_id;
+		u8 slices;
 
 		skl_pipe_wm_get_hw_state(crtc, &crtc_state->wm.skl.optimal);
 		crtc_state->wm.skl.raw = crtc_state->wm.skl.optimal;
@@ -6653,20 +6654,22 @@ void skl_wm_get_hw_state(struct drm_i915
 			skl_ddb_entry_union(&dbuf_state->ddb[pipe], ddb_uv);
 		}
 
-		dbuf_state->slices[pipe] =
-			skl_compute_dbuf_slices(crtc, dbuf_state->active_pipes,
-						dbuf_state->joined_mbus);
-
 		dbuf_state->weight[pipe] = intel_crtc_ddb_weight(crtc_state);
 
 		/*
 		 * Used for checking overlaps, so we need absolute
 		 * offsets instead of MBUS relative offsets.
 		 */
-		mbus_offset = mbus_ddb_offset(dev_priv, dbuf_state->slices[pipe]);
+		slices = skl_compute_dbuf_slices(crtc, dbuf_state->active_pipes,
+						 dbuf_state->joined_mbus);
+		mbus_offset = mbus_ddb_offset(dev_priv, slices);
 		crtc_state->wm.skl.ddb.start = mbus_offset + dbuf_state->ddb[pipe].start;
 		crtc_state->wm.skl.ddb.end = mbus_offset + dbuf_state->ddb[pipe].end;
 
+		/* The slices actually used by the planes on the pipe */
+		dbuf_state->slices[pipe] =
+			skl_ddb_dbuf_slice_mask(dev_priv, &crtc_state->wm.skl.ddb);
+
 		drm_dbg_kms(&dev_priv->drm,
 			    "[CRTC:%d:%s] dbuf slices 0x%x, ddb (%d - %d), active pipes 0x%x, mbus joined: %s\n",
 			    crtc->base.base.id, crtc->base.name,