[Intel-gfx] [PATCH 1/2] drm/i915: Add generic constraint checker when determining DP MST DSC bpp

[Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>]

There are might be multiple contraints which we need to check while determining
if we can use desired compressed bpp, so might be good idea to add a special
helper, so that we don't overcomplicate the main bpp calculation function.

Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
---
 drivers/gpu/drm/i915/display/intel_dp_mst.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
index 8b0e4defa3f1..e3e7c305fece 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
@@ -45,6 +45,13 @@
 #include "intel_hotplug.h"
 #include "skl_scaler.h"
 
+static int intel_dp_mst_check_constraints(struct drm_i915_private *i915, int bpp,
+					  const struct drm_display_mode *adjusted_mode,
+					  struct intel_crtc_state *crtc_state)
+{
+	return 0;
+}
+
 static int intel_dp_mst_find_vcpi_slots_for_bpp(struct intel_encoder *encoder,
 						struct intel_crtc_state *crtc_state,
 						int max_bpp,
@@ -87,6 +94,10 @@ static int intel_dp_mst_find_vcpi_slots_for_bpp(struct intel_encoder *encoder,
 
 		drm_dbg_kms(&i915->drm, "Trying bpp %d\n", bpp);
 
+		ret = intel_dp_mst_check_constraints(i915, bpp, adjusted_mode, crtc_state);
+		if (ret)
+			continue;
+
 		slots = drm_dp_atomic_find_time_slots(state, &intel_dp->mst_mgr,
 						      connector->port,
 						      crtc_state->pbn);
@@ -104,8 +115,8 @@ static int intel_dp_mst_find_vcpi_slots_for_bpp(struct intel_encoder *encoder,
 		}
 	}
 
-	/* Despite slots are non-zero, we still failed the atomic check */
-	if (ret && slots >= 0)
+	/* We failed to find a proper bpp/timeslots, return error */
+	if (ret)
 		slots = ret;
 
 	if (slots < 0) {
-- 
2.37.3