[PATCH 11/11] drm/i915/dp_mst: Add support for forcing dsc fractional bpp via debugfs

[Ankit Nautiyal]

If force_dsc_fractional_bpp_en is set through debugfs allow DSC iff
compressed bpp is fractional. Continue if the computed compressed bpp
turns out to be a integer.

Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal at intel.com>
---
 drivers/gpu/drm/i915/display/intel_dp_mst.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
index 322046bb7d42..26b51ba6871d 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
@@ -172,6 +172,10 @@ static int intel_dp_mst_find_vcpi_slots_for_bpp(struct intel_encoder *encoder,
 		struct intel_link_m_n remote_m_n;
 		int link_bpp_x16;
 
+		if (dsc && intel_dp->force_dsc_fractional_bpp_en &&
+		    !to_bpp_frac(bpp_x16))
+			continue;
+
 		drm_dbg_kms(&i915->drm, "Trying bpp " BPP_X16_FMT "\n", BPP_X16_ARGS(bpp_x16));
 
 		ret = intel_dp_mst_check_constraints(i915, bpp_x16, adjusted_mode, crtc_state, dsc);
@@ -225,12 +229,16 @@ static int intel_dp_mst_find_vcpi_slots_for_bpp(struct intel_encoder *encoder,
 		drm_dbg_kms(&i915->drm, "failed finding vcpi slots:%d\n",
 			    slots);
 	} else {
-		if (!dsc)
-			crtc_state->pipe_bpp = to_bpp_int(bpp_x16);
-		else
+		if (dsc) {
 			crtc_state->dsc.compressed_bpp_x16 = bpp_x16;
+			if (intel_dp->force_dsc_fractional_bpp_en && to_bpp_frac(bpp_x16))
+				drm_dbg_kms(&i915->drm, "Forcing DSC fractional bpp\n");
+		} else {
+			crtc_state->pipe_bpp = to_bpp_int(bpp_x16);
+		}
 		drm_dbg_kms(&i915->drm, "Got %d slots for pipe bpp " BPP_X16_FMT " dsc %d\n",
 			    slots, BPP_X16_ARGS(bpp_x16), dsc);
+
 	}
 
 	return slots;
-- 
2.40.1