[PATCH v4 16/17] drm/i915/vrr: Add function to check if DC Balance Possible

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

Add function to check if DC Balance possibile on
requested PIPE and also validate along with DISPLAY_VER
check.

Signed-off-by: Mitul Golani <mitulkumar.ajitkumar.golani@intel.com>
---
 drivers/gpu/drm/i915/display/intel_vrr.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c b/drivers/gpu/drm/i915/display/intel_vrr.c
index 1275be16e749..a88cc9258542 100644
--- a/drivers/gpu/drm/i915/display/intel_vrr.c
+++ b/drivers/gpu/drm/i915/display/intel_vrr.c
@@ -256,6 +256,22 @@ void intel_vrr_compute_cmrr_timings(struct intel_crtc_state *crtc_state)
 	crtc_state->mode_flags |= I915_MODE_FLAG_VRR;
 }
 
+static
+int intel_vrr_dc_balance_possible(const struct intel_crtc_state *crtc_state)
+{
+	struct intel_display *display = to_intel_display(crtc_state);
+	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
+	enum pipe pipe = crtc->pipe;
+
+	/*
+	 * FIXME: Currently Firmware supports DC Balancing on PIPE A
+	 * and PIPE B. Account those limitation while computing DC
+	 * Balance parameters.
+	 */
+	return (HAS_VRR_DC_BALANCE(display) &&
+		((pipe == PIPE_A) || (pipe == PIPE_B)));
+}
+
 static
 void intel_vrr_compute_vrr_timings(struct intel_crtc_state *crtc_state)
 {
@@ -513,7 +529,7 @@ void intel_vrr_set_transcoder_timings(const struct intel_crtc_state *crtc_state)
 			       lower_32_bits(crtc_state->cmrr.cmrr_n));
 	}
 
-	if (HAS_VRR_DC_BALANCE(display) &&
+	if (intel_vrr_dc_balance_possible(crtc_state) &&
 	    (crtc_state->vrr.dc_balance.vmin || crtc_state->vrr.dc_balance.vmax)) {
 		intel_de_write(display, PIPEDMC_DCB_VMIN(pipe),
 			       crtc_state->vrr.dc_balance.vmin - 1);
-- 
2.48.1