[PATCH v1] drm/i915/display: Add command line param for DC balance

[Mitul Golani <mitulkumar.ajitkumar.golani@intel.com>]

Add a new module parameter 'enable_dc_balance' to allow enabling or
disabling the VRR DC balance feature at runtime. The DC balance
computation in intel_vrr_dc_balance_compute_config() now honours this
parameter, so the feature can be toggled without recompiling.

Signed-off-by: Mitul Golani <mitulkumar.ajitkumar.golani@intel.com>
---
 drivers/gpu/drm/i915/display/intel_display_params.c | 3 +++
 drivers/gpu/drm/i915/display/intel_display_params.h | 1 +
 drivers/gpu/drm/i915/display/intel_vrr.c            | 4 +++-
 3 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/display/intel_display_params.c b/drivers/gpu/drm/i915/display/intel_display_params.c
index 2aed110c5b09..ed3aa84c5d43 100644
--- a/drivers/gpu/drm/i915/display/intel_display_params.c
+++ b/drivers/gpu/drm/i915/display/intel_display_params.c
@@ -120,6 +120,9 @@ intel_display_param_named_unsafe(enable_psr, int, 0400,
 	"(0=disabled, 1=enable up to PSR1, 2=enable up to PSR2) "
 	"Default: -1 (use per-chip default)");
 
+intel_display_param_named_unsafe(enable_dc_balance, int, 0400,
+	"Enable DC Balance (0=disabled, 1=enable). Default: 1 (use per-chip default)");
+
 intel_display_param_named_unsafe(enable_panel_replay, int, 0400,
 	"Enable Panel Replay (0=disabled, 1=enabled). Default: -1 (use per-chip default)");
 
diff --git a/drivers/gpu/drm/i915/display/intel_display_params.h b/drivers/gpu/drm/i915/display/intel_display_params.h
index b95ecf728daa..8c28c27e2c46 100644
--- a/drivers/gpu/drm/i915/display/intel_display_params.h
+++ b/drivers/gpu/drm/i915/display/intel_display_params.h
@@ -46,6 +46,7 @@ struct drm_printer;
 	param(bool, enable_dp_mst, true, 0600) \
 	param(int, enable_fbc, -1, 0600) \
 	param(int, enable_psr, -1, 0600) \
+	param(int, enable_dc_balance, false, 0600) \
 	param(int, enable_panel_replay, -1, 0600) \
 	param(bool, psr_safest_params, false, 0400) \
 	param(bool, enable_psr2_sel_fetch, true, 0400) \
diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c b/drivers/gpu/drm/i915/display/intel_vrr.c
index e36db1174440..1698c54e258b 100644
--- a/drivers/gpu/drm/i915/display/intel_vrr.c
+++ b/drivers/gpu/drm/i915/display/intel_vrr.c
@@ -439,10 +439,12 @@ static bool intel_vrr_dc_balance_possible(const struct intel_crtc_state *crtc_st
 static void
 intel_vrr_dc_balance_compute_config(struct intel_crtc_state *crtc_state)
 {
+	struct intel_display *display = to_intel_display(crtc_state);
 	int guardband_usec, adjustment_usec;
 	struct drm_display_mode *adjusted_mode = &crtc_state->hw.adjusted_mode;
 
-	if (!intel_vrr_dc_balance_possible(crtc_state) || !crtc_state->vrr.enable)
+	if (!intel_vrr_dc_balance_possible(crtc_state) ||
+	    !crtc_state->vrr.enable || !display->params.enable_dc_balance)
 		return;
 
 	crtc_state->vrr.dc_balance.vmax = crtc_state->vrr.vmax;
-- 
2.48.1