[Intel-gfx] [PATCH 06/11] drm/i915: refactor skl_write_plane_wm()

[Paulo Zanoni]

Its control flow is not as easy to follow as it could be. We recently
even had a double register write that went unnoticed until commit
9e44b180f81b ("drm/i915: don't write PLANE_BUF_CFG twice every time")
fixed it. The return statement in the middle along with the fact that
it's on a void function really doesn't help readability IMHO.

Refactor the function so that the first level of checks is per
platform and the second level is for planar planes. IMHO that makes
the code much more readable.

Requested-by: Matt Roper <matthew.d.roper at intel.com>
Signed-off-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
---
 drivers/gpu/drm/i915/intel_pm.c | 33 ++++++++++++++++++++-------------
 1 file changed, 20 insertions(+), 13 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 7fd344b81d66..f388bfa99a97 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -5033,21 +5033,28 @@ static void skl_write_plane_wm(struct intel_crtc *intel_crtc,
 	skl_write_wm_level(dev_priv, PLANE_WM_TRANS(pipe, plane_id),
 			   &wm->trans_wm);
 
-	/* FIXME: add proper NV12 support for ICL. */
-	if (INTEL_GEN(dev_priv) >= 11)
-		return skl_ddb_entry_write(dev_priv,
-					   PLANE_BUF_CFG(pipe, plane_id),
-					   &ddb->plane[pipe][plane_id]);
-	if (wm->is_planar) {
-		skl_ddb_entry_write(dev_priv, PLANE_BUF_CFG(pipe, plane_id),
-				    &ddb->uv_plane[pipe][plane_id]);
+	if (INTEL_GEN(dev_priv) >= 11) {
+		/* FIXME: add proper NV12 support for ICL. */
+		if (wm->is_planar)
+			DRM_ERROR("No DDB support for planar formats yet\n");
+
 		skl_ddb_entry_write(dev_priv,
-				    PLANE_NV12_BUF_CFG(pipe, plane_id),
-				    &ddb->plane[pipe][plane_id]);
+				   PLANE_BUF_CFG(pipe, plane_id),
+				   &ddb->plane[pipe][plane_id]);
 	} else {
-		skl_ddb_entry_write(dev_priv, PLANE_BUF_CFG(pipe, plane_id),
-				    &ddb->plane[pipe][plane_id]);
-		I915_WRITE(PLANE_NV12_BUF_CFG(pipe, plane_id), 0x0);
+		if (wm->is_planar) {
+			skl_ddb_entry_write(dev_priv,
+					    PLANE_BUF_CFG(pipe, plane_id),
+					    &ddb->uv_plane[pipe][plane_id]);
+			skl_ddb_entry_write(dev_priv,
+					    PLANE_NV12_BUF_CFG(pipe, plane_id),
+					    &ddb->plane[pipe][plane_id]);
+		} else {
+			skl_ddb_entry_write(dev_priv,
+					    PLANE_BUF_CFG(pipe, plane_id),
+					    &ddb->plane[pipe][plane_id]);
+			I915_WRITE(PLANE_NV12_BUF_CFG(pipe, plane_id), 0x0);
+		}
 	}
 }
 
-- 
2.14.4