[Intel-gfx] [PATCH 01/11] drm/i915/dp: Check if force dsc bpc <= max requested bpc

[Ankit Nautiyal]

Add a check to use force DSC bpc only if its less that the connector max
requested bpc.

Signed-off-by: Ankit Nautiyal <ankit.k.nauti...@intel.com>
---
 drivers/gpu/drm/i915/display/intel_dp.c | 23 ++++++++++++++++++-----
 1 file changed, 18 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c 
b/drivers/gpu/drm/i915/display/intel_dp.c
index 67089711d9e2..30e8a4bd43ac 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -1474,7 +1474,7 @@ static int intel_dp_dsc_compute_config(struct intel_dp 
*intel_dp,
        struct drm_i915_private *dev_priv = to_i915(dig_port->base.base.dev);
        const struct drm_display_mode *adjusted_mode =
                &pipe_config->hw.adjusted_mode;
-       int pipe_bpp;
+       int pipe_bpp, pipe_bpp_max;
        int ret;
 
        pipe_config->fec_enable = !intel_dp_is_edp(intel_dp) &&
@@ -1483,9 +1483,21 @@ static int intel_dp_dsc_compute_config(struct intel_dp 
*intel_dp,
        if (!intel_dp_supports_dsc(intel_dp, pipe_config))
                return -EINVAL;
 
-       pipe_bpp = intel_dp_dsc_compute_bpp(intel_dp, 
conn_state->max_requested_bpc);
+       /*
+        * If Force DSC BPC is set, try to use that to compute the pipe bpp,
+        * otherwise set pipe_bpp to the max bpp.
+        */
+       pipe_bpp_max = intel_dp_dsc_compute_bpp(intel_dp, 
conn_state->max_requested_bpc);
 
-       if (intel_dp->force_dsc_bpc) {
+       if (!intel_dp->force_dsc_bpc) {
+               pipe_bpp = pipe_bpp_max;
+       } else if (intel_dp->force_dsc_bpc &&
+                  intel_dp->force_dsc_bpc > conn_state->max_requested_bpc) {
+               drm_dbg_kms(&dev_priv->drm,
+                           "Ignoring force dsc bpc:%d, conflict with max 
requested bpc:%d",
+                           intel_dp->force_dsc_bpc, 
conn_state->max_requested_bpc);
+               pipe_bpp = pipe_bpp_max;
+       } else {
                pipe_bpp = intel_dp->force_dsc_bpc * 3;
                drm_dbg_kms(&dev_priv->drm, "Input DSC BPP forced to %d", 
pipe_bpp);
        }
@@ -1497,12 +1509,13 @@ static int intel_dp_dsc_compute_config(struct intel_dp 
*intel_dp,
                return -EINVAL;
        }
 
+       pipe_config->pipe_bpp = pipe_bpp;
+
        /*
-        * For now enable DSC for max bpp, max link rate, max lane count.
+        * For now enable DSC for max link rate, max lane count.
         * Optimize this later for the minimum possible link rate/lane count
         * with DSC enabled for the requested mode.
         */
-       pipe_config->pipe_bpp = pipe_bpp;
        pipe_config->port_clock = limits->max_rate;
        pipe_config->lane_count = limits->max_lane_count;
 
-- 
2.25.1