[PATCH 02/16] drm/i915/dp: Avoid forcing DSC BPC for MST case

[Ankit Nautiyal]

For MST the bpc is hardcoded to 8, and pipe bpp to 24.
So avoid forcing DSC bpc for MST case.

Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal at intel.com>
---
 drivers/gpu/drm/i915/display/intel_dp.c     | 11 +++++------
 drivers/gpu/drm/i915/display/intel_dp_mst.c |  8 ++++++++
 2 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 93aebd3683a4..3d828ea0894d 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -1500,14 +1500,13 @@ int intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
 	if (!intel_dp_supports_dsc(intel_dp, pipe_config))
 		return -EINVAL;
 
-	if (compute_pipe_bpp)
+	if (intel_dp->force_dsc_bpc && compute_pipe_bpp) {
+		pipe_bpp = intel_dp->force_dsc_bpc * 3;
+		drm_dbg_kms(&dev_priv->drm, "Input DSC BPP forced to %d\n", pipe_bpp);
+	} else if (compute_pipe_bpp) {
 		pipe_bpp = intel_dp_dsc_compute_bpp(intel_dp, conn_state->max_requested_bpc);
-	else
+	} else {
 		pipe_bpp = pipe_config->pipe_bpp;
-
-	if (intel_dp->force_dsc_bpc) {
-		pipe_bpp = intel_dp->force_dsc_bpc * 3;
-		drm_dbg_kms(&dev_priv->drm, "Input DSC BPP forced to %d", pipe_bpp);
 	}
 
 	/* Min Input BPC for ICL+ is 8 */
diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
index 8b0e4defa3f1..9be04c60cced 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
@@ -325,6 +325,14 @@ static int intel_dp_mst_compute_config(struct intel_encoder *encoder,
 	/* enable compression if the mode doesn't fit available BW */
 	drm_dbg_kms(&dev_priv->drm, "Force DSC en = %d\n", intel_dp->force_dsc_en);
 	if (ret || intel_dp->force_dsc_en) {
+		if (intel_dp->force_dsc_bpc) {
+			/*
+			 * FIXME: As bpc is hardcoed to 8 bpc as mentioned above,
+			 * Avoid force BPC for now.
+			 */
+			drm_dbg_kms(&dev_priv->drm, "Cannot Force BPC for MST\n");
+			return -EINVAL;
+		}
 		/*
 		 * Try to get at least some timeslots and then see, if
 		 * we can fit there with DSC.
-- 
2.25.1