[PATCH v3 08/15] drm/i915/vrr: Add compute config for DC balance params

[Mitul Golani]

Compute DC Balance parameters and tunable params based on
experiments.

--v2:
- Document tunable params. (Ankit)

Signed-off-by: Mitul Golani <mitulkumar.ajitkumar.gol...@intel.com>
---
 drivers/gpu/drm/i915/display/intel_vrr.c | 25 ++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c 
b/drivers/gpu/drm/i915/display/intel_vrr.c
index 55923eadc3c1..bc99701be2b5 100644
--- a/drivers/gpu/drm/i915/display/intel_vrr.c
+++ b/drivers/gpu/drm/i915/display/intel_vrr.c
@@ -16,6 +16,13 @@
 
 #define FIXED_POINT_PRECISION          100
 #define CMRR_PRECISION_TOLERANCE       10
+/*
+ * Tunable parameters for DC Balance correction.
+ * These are captured based on experimentations.
+ */
+#define DCB_CORRECTION_SENSITIVITY     30
+#define DCB_CORRECTION_AGGRESSIVENESS  1000
+#define DCB_BLANK_TARGET               50
 
 bool intel_vrr_is_capable(struct intel_connector *connector)
 {
@@ -409,6 +416,24 @@ intel_vrr_compute_config(struct intel_crtc_state 
*crtc_state,
                        (crtc_state->hw.adjusted_mode.crtc_vtotal -
                         crtc_state->hw.adjusted_mode.vsync_end);
        }
+
+       if (HAS_VRR_DC_BALANCE(display) && crtc_state->vrr.dc_balance.enable) {
+               crtc_state->vrr.dc_balance.vmax = crtc_state->vrr.vmax;
+               crtc_state->vrr.dc_balance.vmin = crtc_state->vrr.vmin;
+               crtc_state->vrr.dc_balance.max_increase =
+                       crtc_state->vrr.vmax - crtc_state->vrr.vmin;
+               crtc_state->vrr.dc_balance.max_decrease =
+                       crtc_state->vrr.vmax - crtc_state->vrr.vmin;
+               crtc_state->vrr.dc_balance.guardband =
+               DIV_ROUND_UP(crtc_state->vrr.dc_balance.vmax * 
DCB_CORRECTION_SENSITIVITY,
+                            100);
+               crtc_state->vrr.dc_balance.slope =
+                       DIV_ROUND_UP(DCB_CORRECTION_AGGRESSIVENESS * 10,
+                                    crtc_state->vrr.dc_balance.guardband);
+               crtc_state->vrr.dc_balance.vblank_target =
+               DIV_ROUND_UP((crtc_state->vrr.vmax - crtc_state->vrr.vmin) * 
DCB_BLANK_TARGET,
+                            100);
+       }
 }
 
 void intel_vrr_compute_config_late(struct intel_crtc_state *crtc_state)
-- 
2.48.1