[Intel-gfx] [PATCH 08/20] drm/i915: Helper function to update skylake scaling ratio.

[Chandra Konduru]

Helper function updates supported scaling ratios based on cdclk and
crtc clocks.

v2:
-update single copy of scaling ratios (Matt)

v3:
-min scaling ratio is limited by either display engine limit or clocks,
 it is not related to previous ratio (Matt, me)

Signed-off-by: Chandra Konduru <chandra.konduru at intel.com>
---
 drivers/gpu/drm/i915/intel_display.c |   25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 316c4c2..8b2eff4 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -4616,6 +4616,31 @@ static void haswell_mode_set_planes_workaround(struct intel_crtc *crtc)
 	intel_wait_for_vblank(dev, other_active_crtc->pipe);
 }
 
+static void skl_update_scaling_ratio(struct drm_device *dev,
+	struct intel_crtc_state *crtc_state)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	uint32_t crtc_clock, cdclk;
+	struct intel_crtc_scaler_state *scaler_state;
+
+	if (!crtc_state)
+		return;
+
+	crtc_clock = (uint32_t) crtc_state->base.adjusted_mode.crtc_clock;
+	cdclk = (uint32_t) dev_priv->display.get_display_clock_speed(dev);
+
+	if (!crtc_clock || !cdclk)
+		return;
+
+	scaler_state = &crtc_state->scaler_state;
+	scaler_state->min_hsr = max((uint32_t)34, (crtc_clock * 100)/cdclk);
+	scaler_state->min_vsr = max((uint32_t)34, (crtc_clock * 100)/cdclk);
+	scaler_state->min_hvsr = max((uint32_t)12, (crtc_clock * 100)/cdclk);
+
+	DRM_DEBUG_KMS("for crtc_state = %p crtc_clock = %d cdclk = %d\n", crtc_state,
+		crtc_clock, cdclk);
+}
+
 static void haswell_crtc_enable(struct drm_crtc *crtc)
 {
 	struct drm_device *dev = crtc->dev;
-- 
1.7.9.5