[Intel-gfx] [PATCH] drm/i915/skl: Correct other-pipe watermark update condition check

[Kumar, Mahesh]

If ddb allocation for planes in current CRTC is changed, that doesn't
lead to ddb allocation change for other CRTCs, because our DDB allocation
is not dynamic according to plane parameters, ddb is allocated according
to number of CRTC enabled, & divided equally among CTRC's.

In current condition check during Watermark calculation, if number of
plane/ddb allocation changes for current CRTC, Watermark for other pipes
are recalculated. But there is no change in DDB allocation of other pipe
so watermark is also not changed, This leads to warning messages.
WARN_ON(!wm_changed)

This patch corrects this and check if DDB allocation for pipes is changed,
then only recalculate watermarks.

Signed-off-by: Kumar, Mahesh <mahesh1.kumar at intel.com>
---
 drivers/gpu/drm/i915/intel_pm.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 62de97e..a1ed920 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -3127,14 +3127,12 @@ static bool skl_ddb_allocation_changed(const struct skl_ddb_allocation *new_ddb,
 	struct drm_device *dev = intel_crtc->base.dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	const struct skl_ddb_allocation *cur_ddb = &dev_priv->wm.skl_hw.ddb;
-	enum pipe pipe = intel_crtc->pipe;
-
-	if (memcmp(new_ddb->plane[pipe], cur_ddb->plane[pipe],
-		   sizeof(new_ddb->plane[pipe])))
-		return true;
 
-	if (memcmp(&new_ddb->cursor[pipe], &cur_ddb->cursor[pipe],
-		    sizeof(new_ddb->cursor[pipe])))
+	/*
+	 * If ddb allocation of pipes chenged, it may require recalculation of
+	 * watermarks
+	 */
+	if (memcmp(new_ddb->pipe, cur_ddb->pipe, sizeof(new_ddb->pipe)))
 		return true;
 
 	return false;
-- 
1.9.1