[Intel-gfx] [PATCH 1/9] drm/i915: Don't ignore level 0 lines watermark for glk+

[Ville Syrjala]

From: Ville Syrjälä <ville.syrjala at linux.intel.com>

On glk+ the level 0 lines watermark actually matters. Do not ignore it.
And while at it let's change things so that we always program a
consistnet 0 to the register when the lines watermarks is ignored
by the hardware.

Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/i915/intel_pm.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 2a6ffb8b975a..d132ef10fa60 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -4675,6 +4675,15 @@ skl_compute_plane_wm_params(const struct intel_crtc_state *cstate,
 	return 0;
 }
 
+static bool skl_wm_has_lines(struct drm_i915_private *dev_priv, int level)
+{
+	if (INTEL_GEN(dev_priv) >= 10 || IS_GEMINILAKE(dev_priv))
+		return true;
+
+	/* The number of lines are ignored for the level 0 watermark. */
+	return level > 0;
+}
+
 static void skl_compute_plane_wm(const struct intel_crtc_state *cstate,
 				 const struct intel_plane_state *intel_pstate,
 				 int level,
@@ -4757,8 +4766,10 @@ static void skl_compute_plane_wm(const struct intel_crtc_state *cstate,
 		}
 	}
 
-	/* The number of lines are ignored for the level 0 watermark. */
-	if (level > 0 && res_lines > 31)
+	if (!skl_wm_has_lines(dev_priv, level))
+		res_lines = 0;
+
+	if (res_lines > 31)
 		return;
 
 	/*
-- 
2.19.2